the physics of the mind

8/13/2019 the physics of the mind

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Chapter 1

A Birds Eye View of our Quest

This is an overview of the ideas covered in the book, parading manytopics and their authors. This overview is not a direct summary, butserves to set the stage. Part I of the book looks at the hierarchicalstructure of science and physical systems arising from the existenceof different energy scales and length scales. Scientific revolutions oc-cur when different energy and length scales are exposed by new tools.The themes unifying physical law at different length scales and at themost fundamental level are discussed. Part II looks at the emergence of

collective phenomena, self-organizing processes, persistent structures,membranes, living cells, vision, memory, and consciousness as we con-sider increasingly complex systems at human length scales.

1.1 Duality, plurality, and reality

The idea of duality is often used in many traditions to imply that the world that

we live in has a dual character mind and matter, soul and soma, yinand yan,Adam (Om) and Eve (Jeeva), etc. The denial or defence of this duality constitutes

the stuff of most philosophies and religions. Even the methodologies of analy-

sis are categorized as reductionist or constructionist, bottom-up or top-down, and

echo ones attitude to this duality. TheJyanatradition of Buddhism, renamed as

Zen in the hands of Japanese masters, claims to reject duality and embraces a

transcendent holistic unity. Willard Quine, espousing an utterly different secular

philosophical tradition would also end up in demanding a holistic approach[177].

Modern physics, equipped with mathematics, a language infinitely more sub-tle and yet more limited than the language of human transactions, includes not

only opposing dualities, but also commuting and non-commuting realities. How-

ever, in the physics approach, we need to isolate the part of nature that is to be

studied, thus setting up a boundary. These boundary conditions are usually

3


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4 A Physicists View of Matter and Mind

imposed to define a simpler system. This process involves working within a larger

system and reducing a part of it for study. Many problems (see Sec. 2.2) associ-

ated with holism, inductive knowledge, or the theory-laden nature of informa-

tion and such matters can be resolved if the boundary conditions of the reduced

system could be clearly stated. Sometimes the selected boundary conditions may

have unintended symmetries that allow for dualities (Fig. 1.1) or pluralities in the

perceived reality. In practice these symmetries cannot be exactly imposed and a

selection is made by the observer (see Sec. 12.3.1). For instance, perception via

our senses (vision or other), involves an interpretation of the input data where our

brains supply the necessary information for framing it, or breaking the symme-

try. This view plays a prominent role in Gestalt psychology[147].If we isolate bits of matter from each other by setting up suitable boundaries,

then we can study atoms and even smaller constituents contained in them. This is

thereductionist approach of the experimental physicist. The basic building blocks

of physical reality at this scale are excitations of an under-lying energy field.

These excitations may be waves (Fig. 1.2) or particles (Fig. 1.3), depending on

whether you set up experiments designed to chase them along (i.e., determine

the momentum) or catch them in one spot (i.e., determine the position).

Localized excitations of nature at the lowest level of reduction available tous are known as elementary particles. Frequently mentioned elementary parti-

cles are electrons, photons, gluons, neutrinos and quarks. These and other known

building blocks of nature can be cataloged in a sensible, comprehensible way

using what is known as the standard model of particle physics.

1.1.1 Contextuality, non-locality and de-coherence

The existence of a wave-particle duality and its reconciliation are the essen-tial features of the quantum nature of reality which underlies our experience.

In the quantum world, actions are called operations, which themselves have

Fig. 1.1 Duality theGreek vase which flips

into two staring faces orreverts to a vase, as one

keeps on looking at it.The frame, boundary con-ditions, or gestalt struc-

tures needed to interpretthe visual images are pro-

vided by the brain itself.


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A Birds Eye View of our Quest 5

Fig. 1.2 An excitation of a sheet-like surface (an energy field) which is wave-like. The wave isnot specifically localized at any spot but pervades the whole space defined by the boundary.

mathematical analogues known as operators. Their compatibility or incompatibil-

ity is described by mathematical rules (known as commutation rules) somewhatsimilar to the rules of protocol and precedence that we are familiar with, from

actions in everyday life. For instance, in everyday life the operation of crossing

the road and then closing our eyes, could be very different from closing our eyes

and then crossing the road. So the order of operations, and the context matters.

Similarly, sometimes philosophers of science [178]talk ofcontextualityto mean

a similar property analogous to those of the quantum theory.

Another property of quantum systems is their extreme inter-connectedness.

If there are a thousand particles in the system, the behaviour as observed atone end depends on every part of the system, somewhat as in a hologram. The

system is described by a wavefunction which samples every bit of phase space

available to it. A type of correlations found in quantum systems, i.e., quantum

entanglement, is found to involve correlations far exceeding anything that can be

Fig. 1.3 A highly localized excitation of an energy field. This is a particle-like excitation. This isbuilt up by suitably adding (i.e., superposing) a lot of simple waves. An anti-particle can be thought

of as made up of waves which form a depression. Then the vacuum state is the state where theunderlying energy field is flat, in an average sense (i.e., there can be spontaneousfluctuations known

as vacuum fluctuations made up of an equal number of particles and anti-particles). The particle canbe made as sharply localized as we please by using suitable combinations of waves. However, such

wavepackets may not hold together, i.e., stay in coherence, for very long.


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produced using classical inter-connectedness, e.g., as found in a jigsaw-puzzle or

a rubber netting. This brings to ones mind some spooky action connecting any

part of the system to some part not local to it. This non-local property, or non-

localityof quantum systems, is hard to maintain for long, or over long distances,

as the boundaries set up to define the system have to be maintained against all

external disturbances. Otherwise, quantum correlations undergodecoherencedue

to perturbations from outside the boundaries of the system.

The larger the system, the more difficult it is to protect it from decoherence.

If such decoherence effects are ignored, all sorts of paradoxical conclusions can be

drawn. Thus, we do not expect spooky action at a distance within our everyday

concepts of localized reality. Macroscopic quantum phenomena would indeeddisplay spooky action at a distance; but decoherence destroys any such possi-

bility. Furthermore, when we consider many-particle systems. the inter-particle

distance begins to set a length-scale for quantum processes and electrons begin

to form localized chemical bonds (see Sec. 7.3.1). Then normal chemistry takes

over from basic quantum phenomena. Loosely speaking, the resulting decrease

in long-range quantum correlations leads to the property ofnear-sightednesspro-

posed by Walter Kohn. Furthermore, when everyday objects (quantum systems of

many particles) are considered at room temperature rather than at absolute zero,additional considerations (that we discuss in chapter 8) contribute to restore the

reality that is familiar to us. Nevertheless, behind that familiar world, there is an

enriched quantum reality revealed by physics.

In this enriched quantum reality, we have moved from a duality to a multi-scale

plurality in a higher-level unified view of the world, harmonizing the reduction-

ist, holistic and non-commutative content of our knowledge. This does not really

mean that we know the answers to many questions. However, the rise of molecular

biology and neuroscience has presented a clear method of dealing with some ofthese complex questions. Furthermore, the universe is believed to be made up of

dark energy (DE, 73%) and dark matter (DM, 23%). At present we have no idea

of the nature of DE and DM. It is the few per cent of visible matter that is directly

relevant to the human scale of things! This book deals only with those.

1.2 The standard model of matter according to physics

Ancient thinkers distrusted the senses and resorted to introspection and usually

had an idealist view of the world, although there were some materialist thinkers

who were more close to the practical technologies that were known as natural

philosophy. This tradition, combined with the interrogation of nature via


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experiments evolved into the disciplines of modern science. This was driven on

the one hand by pure curiosity and theorizing about the world, and on the other by

the activities of conquest, commerce, and social organization. Later in the book

we discuss the nature of scientific knowledge and how successive theories have

arrived at the contemporary views of our world. The most successful view of the

world is the one codified by scientists who have investigated the external world

as a system made up of matter and its interacting fields. Here we use the word

scientist loosely to include chemists, biologists, geologists, physicians, engi-

neers and others even in the social sciences who use the methods of natural

philosophy.

The standard model of physics attempts to describe all phenomena with afew dozen fundamental particles, and energy fields that mediate the interactions

among these particles. If we include fields, particles as well as their anti-particles,

we need some five dozen fundamental objects in the standard model. Obviously

this is too many for the economical mindset of the theoretical physicist, or that

of the mystic who wants every thing to come out of a single sacred word likeOm.

These fundamental objects may well be the varied manifestations of some

other, even more fundamental field. However, the laws associated with these ele-

mentary objects, viz., the laws of physics, are amazingly simple and fascinating.Chemistry, biology, and the more complex stuff of the world are all regarded as

consequences of the laws of physics. A popular, easily readable presentation of

this point of view (which is also largely shared by this book), has been given by

Murray Gell-Mann inThe Quark and the Jaguar[83].

For our purposes, the standard model is a sufficiently fundamental starting

point. Hence in this section we give a brief account of the standard model of

matter, as formulated in the latter half of the 20th century. Many physicists con-

tributed to this model [4]which eventually took formal shape in the hands ofAbdus Salam, Steven Weinberg, and Sheldon Glashow.

Physics reveals that matter is made up of atoms which are mostly empty

even more empty than the solar system where there are asteroids and debris in the

vast spaces between planets. Everything that matters to humans depends mainly

on what goes on at the very edge of these atoms. Chemistry happens at such edges.

Biology happens at an even larger length scale, at the edges of molecules. Never-

theless, the inner structure of matter, as seen in the very core of atoms, and in the

sub-nuclear world, turns out to be directly connected with questions of cosmologyand the large-scale structure of the world in regard to space and time. Hence, the

nature of the world at very general length scales, from the smallest to the largest,

is of great interest. We examine selected aspects of physical theory in detail in

later chapters of the book. Hence, the following section may be skipped or merely

skimmed by the readers whose interests reside in larger length scales.


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1.2.1 Atoms, nuclei, quarks and quantumfields

Matter appears to exist in various phases, i.e., solids, liquids, gases etc. Many

idealist philosophies of the East and the West have attacked this, by claimingthat all reality is mental, or that it is an illusion a Maya. The ordinary per-

sons reaction to such philosophical doubt is typified by that of Dr. Samuel John-

son to Bishop Berkeleys public statements. Bishop Berkeley (16851753) was a

philosopher whose public claims irked Dr. Samuel Johnson, a literary luminary

of the period and compiler of the first English dictionary. Johnson is supposed

to have refuted such views by proving the existence of matter by kicking a

stone. We mention this because the physicists approach to understanding matter

is indeed based on kicking matter in various ways. The physicist probes matterwith projectiles, heat, intense light, or chemicals that are just other forms of mat-

ter. One approach would be to use increasingly energetic probes to penetrate or

bombard matter, and then examine the debris of the collision to understand the

composition of the targeted matter. Today such experiments are done using par-

ticle accelerators, e.g., at CERN, that provide well controlled particles of known

energy, for use as missiles, to be directed at atoms, nuclei or other objects under

study.

Initially, natural fast particles were used as the energetic probes. Radioactiveatoms emit energetic -particles, later identified to be Helium nuclei. Ruther-

ford, Geiger and Marsden (1909) studied how -particles are scattered from

atoms, and showed that atoms are not hard diminutive marbles. They are mostly

empty space containing a positively charged, heavy, point-like central core (nu-

cleus) and very light negative charges (electrons) distributed sparsely around it.

Similar scattering experiments targeting nuclei revealed that nuclei are also

not point particles, but are made up of even smaller particles named protons and

neutrons. The nucleus appeared point-like only for the rough probes (less en-ergetic particles) that could only resolve the larger length scales of atoms and

molecules. Protons and neutrons are collectively called nucleons. They are also

called baryons as they are heavy compared to electrons which are classified aslep-

tons. Leptons have a spin angular momentum of (1/2) in units ofh, the quantum-

unit of angular momentum. The photon is a zero-mass particle but not included

with leptons as it has an angular momentum of unity. Subsequently, intermediate-

mass particles were identified, especially in Cosmic ray showers. They are known

asmesons. Mesons decay into electrons, positrons, neutrinos and photons. They

are particles with integral values of spin (in units ofh). Baryons and mesons are

collectively calledhadronsas they display short-ranged, hard interactions.


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Thus, taking the proton mass as the unit, an Aluminum nucleus with a mass

of27 consist 13 protons and 14 neutrons interacting among them and holding

together. The Al atom is mostly empty space, containing a nucleus of 27 nucle-

ons at the tiny core, and 13 electrons distributed at length scales which are many

thousands of times larger than the size of the nucleus. The radius of a nucleon is

of the order of a femtometer (1015m), while the radius of an atom (1010m) is

some 105 times larger. A human hair is some ten million times thicker.

The strong repulsion among positively charged protons is balanced by the at-

tractive forces among the nucleons. The proton,p, and the neutron,n, have almost

the same mass, and since mass and energy are equivalent (E=mc2), Heisenberg

in 1932 suggested that thepand nwere a manifestation of the same particle intwo nearly identical energy states. This basic particle is assigned a property called

isospin defining two states (which may be termed up, down, or p, n). If you

are in space where up and down do not matter, there should be no distinction

between these two particles. This deep symmetry is mathematically denoted by

the symbol SU(2). That there is such a distinction between pandnshows that the

isospin symmetry is broken. The isospin concept, which involves a non-Abelian

gauge symmetry (see Sec. 3.5), enabled nuclear physicists to classify the internal

energy states of nuclei, and propose that there is aweak interaction that splits theexact degeneracy between the proton and the neutron, thus making their ground-

state energies (i.e., rest masses) slightly different in energy. The isospin concept

explained the existence of other heavier relatives of the proton and the neutron,

like the (Lambda), (Sigma), and the (Xi) particle. Meanwhile, Diracs the-

ory (Sec. 6.10.2) of electrons and their anti-particles led naturally to the concept

of anti-particles being associated with every type of particle.

The establishment that quantum particles have wave properties, and vice versa,

meant that particles have fields associated with them, and fields have particlesassociated with them. The photon is the field-particle of the electromagnetic field.

Nucleons were postulated to interact via pions (). However, although,0,+ particles were

discovered, we see below that nucleons and pions are themselves composite structures whose interac-tions occur at a deeper level involving quarks and gluons.

Arep,nand other baryons point-like particles? In a sense, the question is meaningless as sizeis not an attribute of a particle. A particle can have mass, charge, spin, isospin, helicity and so on,but its size only appears in terms of the scattering cross-section when probed with other projectiles.

When composite particles are probed, they can split into smaller fragments. Free neutrons, and indeed

all baryons are unstable. The neutron decays into a proton emitting an electron, and an anti-neutrinodenoted by the symbole. The latter is a particle with nearly zero mass and postulated theoreticallyby Wolfgang Pauli in 1930. It was observed only in 1956. Hence neutrons were already suspected to

be composite particles. Protons seemed to be stable elementary particles but today we know better.Scattering experiments on nucleons, and results from cosmic ray studies where unknown inter-

mediate mass particles, i.e., mesons () were found, suggested a deeper set of particles at yet higher


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Table 1.1 The elementary particles, i.e., the building blocks of Nature used in the Standard Model.

Particles Fields

quarks charge leptons fields interactions particle

up 2/3 e Electro-magnetic

e.g.,electrons-

positron

photons

down 1/3 e QED

charm 2/3 Chromo-dynamics

e.g.,inter-quark

gluons

strange 1/3 QCD

top 2/3 Electro-

weak

muon decay W and Z

bosonsbottom 1/3

Higgs field sets masses Higgs

particle

gravitation interacting

masses

gravitons

energy scales and controlled by even deeper symmetries. In 1964 Murray Gell-Mann and George

Zweig proposed that baryons were made up of quarks, i.e., unusual particles of fractional charge.The quark concept was proposed by Gell-Mann and Neemann in 1961 harnessing the symmetry

known mathematically as SU(3), i.e., a generalization of the two-fold symmetry contained in Heisen-bergs SU(2), to present a fascinating eight-fold symmetry based on three fractionally charged particlesknown as quarks. This was a non-Abelian gauge symmetry (see Sec. 3.5) hidden deep inside the sub-

nuclear structure of matter. This theory had revolutionary features, like proposing fractional charges

for the quarks, a name borrowed by Gell-Mann from James Joyces Finnegans Wake. Additionalfeatures of the theory meant that the quarks could not exist freely, but could only be found enslaved

as components of nuclei. Thus, according to the quark theory, the eight baryons (neutron, proton, ,

0, 0,, and ) all form an Octet made up of various combinations of theu,dandsquarks.

The theory had to face a decade of skepticism. However, the theory systematized the known

facts, predicted new particles and their experimental masses. The year 1974 was very eventful forparticle physics as experimental evidence tumbled in from the Stanford Linear Accelerator (SLAC)

and Brookhaven, confirming the new theories. These experimental groups discovered, independently,states of a type of quark (known as the charm quarkqc) bound to its anti-particleqc . Such bound states

are analogous to the electron-positron bound-pair, and are known as charmonium. The lowest energystate of charmonium is known as the J/particle. Other predictions of the theory were also verified

in the heady years following 1974.We briefly summarize the quark model of elementary particles (see Table 1.1). The earliest known

family consisted of two quarks, called the up-quark (qu) and the down-quark (qd), and two leptons,called the electron (e) and electron-neutrino (e). The names up, down are simple labels and

nothing more (i.e., names, like Paul and Peter). The neutrino was a name given by Fermi, for a neutralparticle which probably has nearly zero mass and postulated by Pauli.

Experiments, as well as theory using symmetry and conservation laws revealed two other quark

families. Thus we have the muon family which contains the strange quark and the charmed quark(qs,qc), and the associated leptons called the muon and the -neutrino denoted by (,). Finally,

the tau-family, contains the top quark and the bottom quark (qt,qb), and the leptons (,).


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The Higgs particle, proposed by Peter Higgs and others in 1964 is included in

Table 1.1, and had eluded confirmation up to the first decade of the 21st century.

The standard model does not explain why the particles have their observed rest

masses, but assigns them in terms of interactions with the Higgs field. To sim-

plify matters drastically, the Higgsfield may be conceived as providing resistance

to longitudinal excitations (thus providing mass to them). This does not affect

photons and other transverse excitations. The Fermi Lab physicists had dubbed

it the god-damn particle because of its elusiveness. However, Leon Lederman,

the director of the Lab had to change the nickname to the God particle in writ-

ing a popular book about the Higgs, and other particles. Experiments at the Large

Hadron Collider (LHC) at CERN in July 2012 have revealed signals in the

125GeV region, providing strong support for the Higgs mechanism.

We have included gravitons in the Table, being the bosons that mediate gravity

in a quantum field. The relevant theory of quantum gravity is not yet known.

Quantum chromdynamics (QCD) is a quantum filed theory elaborating on

quantum electrodynamics (QED) where the excitations are called quarks and glu-

ons. Quarks can have three varieties of charge, known as color. The colors

must always neutralize each other to give no color (color singlets). Thus we have

the three colors red, green and blue. The antiquarks carry the anti-colors,just as a positron carries the charge opposite to an electron. Unlike QED which

obeys Abelian Gauge symmetry (Sec. 3.5), QCD involves a non-Abelian gauge

symmetry. The color here is just a label; the spelling of color is that used by

Gell-Mann, a founding father of quark theory and an accomplished linguist.

What is the nature of a quark? Why is the electron charge exactly equal to that

of a proton? If quarks cannot be seen in a free state, but only as bound states of

one another, can all of them be excitations of something even more fundamental?

Would such a theory bring in the graviton also as one of the excitations that arisenaturally from the theory, thus doing away with General Relativity as a separate

theory for gravitation which stands outside the quantum theory?String theoryis

one such attempt to provide a more compact grand unified theory (GUT), a name

introduced by Schrodinger already in the 1940s. In string theory, the elementary

particles and fields are conceived as excitations of one-dimensional objects called

strings. This theory is at present only a research program without new predictions

in the energy and length scales currently accessible to experimentalists. The LHC

may provide the experimental results at higher-energy scales and shorter lengthscales where the Standard Model needs modification. However, only a small sub

set of the standard model is needed for understanding matters at the human scale

of things. Hence new experiments from CERN etc., are not expected to change

biochemistry and physiology that work at very low energy scales.


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1.3 Scales of energy and length

Consider the nascent universe or at least, the part accessible to us. It begins

in some highly energized metastable initial state sometimes called a false vac-

uum state. We dont know much about this state but attempt to deduce whatever

we can about it. Unlike ancient philosophers, theoretical physicists are guided by

mathematics as well as the laws they have uncovered. By vacuum we mean an

initial state with no excitations in it. We know that there are fluctuations in any

vacuum, i.e., zero (or emptiness) is after all made up of1 and +1, or 2 and

+2, as they add to zero when averaged. Thus we may think of vacuum fluctuations

in terms of lots of1s and +1s distributed randomly. That is, the vacuum is empty

on the average, and yet it is full offluctuations. These fluctuations or excitations

of the vacuum are what physicists call elementary particles, like electrons and

positrons, gluons, quarks etc. One could think of a very large energy fluctuation

putting the system into a metastable false vacuum.

As we move from the very high energy scales of elementary particles towards

smaller energy scales, interactions (among the particles known as gluons and

quarks) give rise to more complex particles like protons and neutrons. These are

made up of quarks, where the inter-quark interactions are more or less balanced.The forces between nuclei are the weak remnants of the inter-quark forces left over

after the formation of nucleons. The lightest nucleus is the proton. The proton is

the nucleus of a hydrogen atom. If it were a sphere, its radius would be about

1 1015 m, i.e., a femtometer. Nuclei and electrons interact via the exchange

of photons (they are the elves of the electromagnetic field). Electrons and nuclei

form atoms that are many orders of magnitude bigger than nuclei. A proton and an

electron bind to become a hydrogen atom. The radius of the hydrogen atom (the

Bohr radius) is about 5

1011

m. It sets the length scale of atoms and moleculesand is known as anatomic unitof length which is about a million times bigger than

the scale of nuclei. Thus at each stage, the parameters, or factors which determine

the reality at the lower scale, get replaced by new, more extended or coarser types

of parameters or collective variables. However, as the length scales get bigger and

bigger, the energy scales get smaller and smaller. That is, energies associated with

nuclear forces are enormous, compared to the energies associated with electronic

states of atoms which are counted in electron-Volts (eV). Molecular-formation en-

ergies are even more fine grained, and are counted in milli-electron-volts (meV),i.e., a thousandth part of an eV, or even in calories.

Molecular Energies, e.g., body heat at 37C is in the 25 meV. range. Thiscorresponds to infrared light.

Energy levels in atoms are in the eV range; e.g., the hydrogen atom has an


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ionization energy of13 eV, similar to the thermal energy of an object heatedto 151,000 K. The visible, ultra-violet and X-Ray range are reached with heavieratoms. Atoms and small molecules are nanoscale (109 meters = 1 nm) objects.

Nuclear energies are given in MeV (106 eV). The temperatures inside the sun arein this,-ray regime. Nuclei are many orders of magnitude smaller than atoms.

The rest mass m0 of an elementary particle corresponds to an energy m0c2,

wherecis the velocity of light. These energies range from MeV to hundreds ofGeV and up. The CERN laboratory attempts to reach such high energies.

The primary patch of spacetime that underwent exponential expansion (inflation)during the big-bang is about 1036 meters in size (i.e., at least a hundred-billion-billion times smaller than a proton). The Planck energy scale that prevailed inthe earliest universe is believed to be 1019 GeV.

This sequence is also dictated by the four fundamental forces of nature that emerge

as the universe cools down from its initial intense heat (See Fig. 1.4).

Strong interactions prevail between quarks, which are the components of heavynuclear particles (e.g., protons, neutrons), known as baryons. The gluons arethe excitations that mediate the interaction among the quarks. The quarks haveflavors and colors these are just descriptive name tags. The excitations ofthis force field, known as the chromodynamic field, are quarks and gluons. Thestrong interactions have a short range comparable to the size of a nucleus, i.e.,about a femtometer (1015 m).

Weak interactions (WI) are a million times weaker than the strong interactions.These are very short-ranged interactions, dying off within a billion-billionth of ameter (1018 m). WI are capable of changing the flavors of quarks. This force ismediated by two particles known as the W-boson and the Z-boson. The W-bosonis charged, while the Z-boson is not. These two particles are similar to the photon,except that the photon has no mass. Also, the energy of these particles is associ-ated with a shoving backwards and forwards motion (longitudinal oscillations),unlike the photon which carries its energy with an up-down motion (transverse

oscillation) relative to the direction of propagation. The WI can change a pro-ton to a neutron and vice versa. The weak interaction and the electromagneticinteraction, mediated by the three bosons (the photon, W boson and Z boson) aregrouped together under the name the electro-weak interaction.

The electro-magnetic interaction. This interaction governs our entire everydayworld of physics, chemistry, cyberspace, life and neural activity. The ratio of thestrength of the electro-magnetic interaction to the strength of the strong interac-tion is called the fine-structure constant. It is equal to 1/137. When you sit ona chair, it is the electrostatic repulsion between the electrons in your body, and

the electrons in your chair, which you feel as a hard surface. Samuel Johnsonis said (by Boswell, the biographer of Johnson) to have used the hardness of akick in refuting Bishop Berkeleys idealism, i.e., just the Coulomb repulsion oflike charges! It is also the energy in thunder, lightening and laughter. The photoncarries the energy of this interaction. Unlike the strong and weak interactions, ithas an infinite range of action. That is, electrostatic forces decrease as 1/r2 (the


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Coulomb law), and the electrostatic potential decreases as 1/r. Finally, there is the weakest of all forces, namely, gravity. Since gravity also

obeys Newtons inverse square law of force, 1/r2, gravity has an infinite range.

It becomes weaker and weaker, but ever so slowly.

Just as the six sides of a dice are found to be manifestations of the same single

object (i.e., the dice), one would like to understand how to obtain a unified view

of all these fundamental forces.

In Fig. 1.4 the universe is assumed to begin in some unknown manner, from a

very hot, dense, initial state (metastable vacuum). This leads to an exponentially

expandinginflationphase. The inflationary theory of the early universe (i.e., the

first 10

35

sec) is driven by ideas from the quantum Theory (QT). This theorythen partly hands over the discussion to the theory of General Relativity (GT)

which also predicts the existence of space-time singularities (i.e., mathematically,

situations where the solutions seem to require dividing by zero, or lead to some

such mathematically uncontrolled situation). Examples of such singularities are

black holes where spacetime collapses, or big bangs where spacetime blows up.

We are concerned with Thebig bang (BB) explosion associated with a sin-

gularity in the field equations describing our part of the world, restricted by our

event horizon. Of course, there can be many such BBs going on in the multi-verse, just as there can be many bubbles in a boiling kettle. But we are trapped

in our BB bubble, so our knowledge is restricted to our BB. General Relativity

becomes increasingly inapplicable at the short lengths associated with the singu-

larity. In fact, here we are thinking of lengths perhaps as small as what is known

asthe Planck lengthwhich is about 1035 meters. Thus the initial universe must

be discussed using some theory other than GR. However, the cosmology that de-

veloped in the middle of the 20th century, in the hands of Gamow and others[14],

predicts the big bang using the physics of general relativity. In the 1948 paper byGeorge Gamow et al., where the author names (Ralph Alpher, Hans Bethe, George

Gamow) are arranged to sound like the first letters of the Greek alphabet (,,),

they showed how the relative abundances of elements found in stars, as deter-

mined by spectroscopy, could be used to deduce the physical conditions which

existed in the early universe. Thus the inputs to the Big Bang theory included

well-established spectroscopic information, nuclear physics and relativity.

Inflation theory discusses an even earlier period of the universe, before the for-

mation of nuclei or elementary particles. The rise of string theory in the 1980s, andthe more recentm-brane theory (see Sec. 5.9.1) inspired the ideas[134] behind the

inflationary model of the universe. Inflation involves the exponential stretching

of the original patch of instability to an enormous extent in an incredibly short

time. The simple symmetries that existed in the early universe evolved into new


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UNKNOWN BEGINNIGSInflation, Big Bang

E=1019

GeV; T=1032

K

PlankScale

Unkownquantum

fluctuations

Quantum gravity

10-50

s

El e c t

ro -we a k

Inflation

Gra v

it y

S t ro

n g In

t e r a c t io n s E

le c t ro ma g

e n t ic

We a k

in te r a c ti o

n s

10-35

s

Elector-Weaksplits at~100 GeV

Quarks formnucleons,ions combine

Space becomestransparent

to Light,

105years,

Galaxies etc.

formed

Hubble expansionNow= 14 billion years

GUT

1027

K

1015

K

Cosmic

Micro-wave

background

2.7 K

i n te

ra c ti o n s

in t e r a c t io

n s

Fig. 1.4 As the early universe cools, the high-symmetry of the grand-unified theory (GUT) spawns

the lower symmetries of the Standard model in 1010 s. Four types of interactions, viz., gravity,electromagnetic, weak, and strong interactions emerge. The high energy scales and short length scales

get replaced by smaller energy scales and bigger length scales. These allow many energy states to existin a narrow range of energies, allowing the emergence of complex systems typical of biology.

symmetries, and the four fundamental interactions shown in Fig. 1.4 emerged. Asthe universe cooled, elementary particles combined to form complex composites.

Large scale structures like galaxies formed i.e., the very short Planck scale of

length (see Secs. 5.9, 5.8) has now got replaced by much bigger length scales.

It is this fine-graining of the energy, associated with the coarse-graining of the

length scale that brings about complexity from the simplicity of the elementary

interactions. At the molecular level, the energy scales are much smaller than at the

atomic-scale. Thousands of molecular energy configurations are possible within

an energy range where only one or two atomic states are possible. Atoms andmolecules give rise to more fragile biological structures (cells, plants and animals)

having more coarse-grained (i.e., bigger) length-scales pertaining to the biological

world. As we move from the atomic world to the biological world, the boundary

conditions defining the way we isolate the system for study become different to


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those in the quantum world. The higher-level variables usually contain collective

effects as well as damping effects or decoherence factors which determine the

lifetime of the new, higher-level variables.

In technical jargon one would say that the propagators (Greens functions) describing the exci-

tations no longer have sharp, discrete poles instead the poles have become complex, with branch-cuts. These new modes represent new physics appropriate to the new characteristic energy scales.

Herbert Simon[197] argued in 1962, in an essay entitled The architecture of

Complexity, that complex systems are organized in a hierarchical fashion. Thus

sub-atomic particles build atoms, atoms make molecules, cells, organisms, organ-

isms make tribes, societies and nations. Here Simon too was discussing energy

scales and length scales. On the other hand, Landau and Ginzburg had formu-lated a very beautiful and comprehensive quantitative theory of order mainly for

physical systems, but equally applicable to any complex system. When dealing

with physical systems, the energy scales and length scales are globally useful,

convenient measures of hierarchical position. The history of science itself can be

understood (Sec. 2.4.1) as an unraveling of new energy and length scales as our

tools gets sharper and more powerful. New theories are needed to encompass these

new energy scales and length scales.

In this book we argue that the appearance of collective modes, moderatedby damping and decoherence, and involving complex systems with many nearly

equivalent energy minima introduces irreversibility and indeterminism into our

physical theory, paving the way for a theory of the mind where consciousness and

free will, deductive reason and intuitive insight, become comprehensible within a

relatively standard interpretation of physics and chemistry.

1.3.1 Hierarchical structure in logic, language and life

This hierarchical structure that emerges as we move from elementary particles

(e.g., electrons, photons, quarks etc.) to more complex objects, as well as the in-

determinism arising from the damping effects at each stage is also seen in other

systems as we go from simplicity to complexity. Very simple formal-language

systems, e.g., those containing a few symbols and a few strings (sentences) de-

rived using a basic set of rules, are such that all statements in such a language

are logically related to each other. Such a language, or a propositional calculus,may be said to be complete, or closed. Russell and Whitehead, in theirPrincipia

Mathematica, attempted to show that mathematics is such a complete, consistent

system derivable from the axioms of logic. Such sentences would be called ana-

lytic sentences by the Logical Empiricists who were very influential in the early


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half of the 20th century. Russell and Whitehead hoped to reduce all arithmetic to a

system of logical relations among sets or groups. A set is simply a collection

of elements that obey specified rules of transformation, e.g., addition, associa-

tion, commutation etc. However, this effort unearthed various logical paradoxes,

e.g., Russells paradox of sets, which suggested that self-referential statements in

a language have to be made using a higher-level meta language.

The set of tables is itself not a table. Thus we have sets which are not members of themselves. Theset of ideas is itself an idea, and hence should be a member of itself. Now, is the set of all sets whichare not members of themselves, contained in itself or not?

The meta-language will have its own meta-paradoxes. A landmark result

from the foundations of mathematics is the now famous Godels theorem, whichshowed that formal systems, if they are sufficiently complex, contain valid state-

ments not deducible within the formal system. A similar result in computer sci-

ence is known as Turingshalting theorem, and asks if a computer can decide by

itself that it has solved a given problem, and come to a halt on its own.

In this book we examine the hierarchical structure moving from elementary

particles to atoms, molecules, cells and other complex adaptive systems includ-

ing human beings. A human is both a biological organism and a person. Is s/he a

conscious machine? On your table you have a computer, an able robot executingmany complex algorithmic operations for you. It may even use algorithms based

on neural-network models (see Sec. 2.2.5). It will do this as long as the computer

is maintained at the voltages and power levels specified by the manufacturer, and

as long as the conditions of humidity and temperature remain within factory spec-

ifications. You can open several windows and the computer behaves as several

virtual computers doing several tasks, as long as you obey rules about creating

such windows. The computer is a system that inputs energy, outputs wasted en-

ergy (entropy), and performs tasks. It interacts with you in a predictable way.Across the table Bob is seated opposite you. In fact, there are two individu-

als, you and him two personalities. The inter-personal interaction occurs via

Fig. 1.5 Bertrand Russell, Kurt Godel, and Alan Turing (courtesy APS archives).


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language, gestures, and within social conventions of protocol and precedence

commutation rules that exist between you. These are related to the variables

that are effective at this level of coarse-graining of the physical world. On the

other hand, he can be seen as a thing, i.e., anit. That is, a conglomeration of cells

held by biochemical forces, and showing a bio-chemical characteristic known as

being alive (existence). Existence depends on the input of energy and nutrients,

the presence of thousands of other living bacteria in the gut and other parts of

the body. It is really many living organisms working collectively, with no specific

part identifiable as the individual named Bob. He is in many ways a biologi-

cal computer. The architecture for his/its construction is specified in Bobs DNA.

This DNA embodies the specifi

cs of Bob that encodes Bob suffi

ciently for him tobe uniquely identified. In fact this code is used incessantly to repair and replen-

ish body components (cells) which need to be replaced due to wear and tear. The

copying process itself introduces errors, wear and tear, leading to a gradual aging

of Bob. That is, just as my desk-top computer is constantly updated and repaired

(viamy on-line connection to the manufacturer who knows the basic architecture

of my computer) against wear and tear etc., Bobs system is also updated, by a

self-contained system of protein synthesis and cell repair.

Knowing Bob for many years, his behaviour is reasonably predictable. Also,just like the computer, he has several windows or personalities. If his body tem-

perature, oxygen intake, blood-sugar level, or serotonin level in the brain were

modified by even a few per cent, he too, just like a computer which is deviating

from specifications, begins to behave strangely and in unpredictable ways. Who

then is Bob? Is he a bio-chemical computer? Or is he the person that you have

known for many years? Clearly, they are two different ways of looking at the same

object. Figure 1.1 displays the dual image of a Greek Vase which also looks like

two human faces, depending on the glancing stance used by the perceiver. The re-lationship between the image of Bob as an organism, or as a person is clearly more

subtle. Many philosophers or religious thinkers would argue that the move from

Bob the organism, to Bob the living, conscious individual who is, say, a lawyer, a

husband, a father, a colleague and a friend, involves some esoteric principle or

an elan vitalebeyond analysis or reductionism. The electronic computer needs

some one to give it commands. Is it too much to envision a self-learning com-

puter which constructs its own commands and generates its own responses, based

on the inputs it receives from the outside world? Isnt that Bob?In the 19th century, it was believed that certain chemical substances (organic

compounds, e.g., acetic acid or vinegar) found in living matter could not be made

in the laboratory. Only living matter could produce them. Similar impossibility

barriers, from sugar to chlorophyll and DNA, were suggested from time to time,


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and yet they have all been surpassed. The complete analyses of the coding in the

DNA of the primitive wormCaenorhabditis Elegansand other benchmark organ-

isms, and finally the human Genome itself have been completed. The role of each

gene in the neural wiring and behaviour ofC. Elegans and similar small organisms

are now well understood. Synthetic organic chemistry can use the very techniques

of nature to create novel proteins that never existed in nature. The cloning of large

animals, developments in computer science and neuroscience have generated new

optimism, especially among life scientists, that the gap between Bob the mech-

anistic organism, and Bob the person may finally be bridged, without claiming

mysticism. It is true that higher-level variables can control lower level variables

(as happens when you, a higher-level complex-adaptive system, decide to move aknight in a chess game). However, the effect of the higher-level variables is to set

the boundary conditions that constrain the physical laws of the lower-level. They

do not change the validity of the microscopic description.

A number of physicists have invoked the quantum theory to claim that a

conscious observer is an essential feature of reality. This view, starting from

von Neumann and Wigner, is presented in, e.g., Mind, Matter and Quantum

Mechanicsby Henry Stapp [201], in Hameroff and Penrose (see Ch. 13) or in

Quantum Enigma: Physics encounters consciousnessby Rosenblum and Kuttner[182]. While Eugene Wigner and others began this discussion in the context of

what is known as the measurement problem in the quantum theory, some writers

have spun a highly metaphysical, even sensational picture of reality. Thus, the run-

ning of computers, lasers, atomic clocks and all the physical underpinnings of the

modern world depend on some almost magical act of observation giving reality

to the world. This reality, generated by the observer may be a mere momentary

selection from an infinity of many worldsa laEverett[56].

We discuss the measurement problem and the quantum paradoxes in Ch. 7.Quantum Enigmas and the role of the observer get clarified when the boundary

conditions (BC) associated with the preparation of the system are included in

the discussion. This is neatly done in David Bohms approach where the effect

of the BC enters into the Bohmian quantum potentials. Specifying the boundary

conditions to sufficient accuracy brings in all the issues of sensitivity to the input

information, as well as Bayesian or other estimates of the probablevalidity of such

information. Not surprisingly, some writers (e.g., Caveset al.[44,77]) have gone

back to review the meaning of probability to elucidate quantum mechanics.When dealing with many-particle systems at human length scales, decoher-

ence and finite-temperature (finite-T) effects have to be taken into account in a sys-

tematic way, so that popular metaphysical views associated with Schrodingers

cat etc. (see Ch. 7) do not cause confusion.


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Density-functional theory (DFT) states that a quantum systems can be com-

pletely described by a functional of the density distribution, Hence it dispenses

with the many-body wavefunction. This resolves many issues in understanding

quantum reality. DFT can conveniently treat finite-Tsystems, without heavy

formulations like thermo-field dynamics etc., and seamlessly treat classical and

quantum hybrid systems. Thus, in our view, the quantum theory, discussed in

Part I of this book, presents a very comprehensible non-mysterious resolution of

dualities, subjectivities and paradoxes that plague many discussions.

The early part of the book will look at the nature of physical law, scientific the-

ories, and the critiques of some philosophers of science who have developed a new

genre of science studies where they claim that science is reducible to a relativismof belief a socio-political belief system. Having dealt with such epistemologi-

cal questions, we go on to study the basic laws of physics, emphasizing how the

quantum theory of elementary particles, relativity and the underlying laws of sym-

metry and simplicity pave the way for complexity. A remarkable epistemological

consequence of the simplicity of the laws of physics is the emergence of a form

of teleology in the principle of least action (Sec. 3.6). A few symmetry rules, least

action, and the equation of continuity seem to be the essential underpinning of the

laws of classical physics as well as modern physics.The world of atoms, molecules and ions involves longer length scales and

smaller energy scales. However, it is still governed by the same basic laws. How-

ever, the deterministic interactions among charged particles at low-energy scales

lead to collective modes like plasmons which have acquired a degree of indeter-

minism (reflected in the complex-pole structure of their propagators) by deco-

herence and by the loss of information across the boundary of the system. Other

classes of collective modes are charge-density waves, magnetic structures, and

crystalline order that self-assemble in materials systems.In Part II of this book we examine the path of astrochemistry and pre-biotic

chemistry of the early earth. The formation of incubators of living organisms

in various type of Darwins warm little ponds, and in hydrothermal vents are

discussed. Froth bubbles, lipid bilayers, and biological structures (Sec. 10.4.2)

are also self-assembled complex molecular quasi-equilibrium systems. Quasi-

equilibrium stationary states of such material systems, formed within naturally

formed lipid bilayers may involve feed-back loops that allow for adaptive mod-

ifications of the structure of such systems to conform to the requirements of theambient environment. Such systems can form classes of complex adaptive sys-

tems which utilize (i.e., feed on) lower-scale systems for maintaining their sta-

tionary state. Such systems which can replicate themselves are essentially living

organisms. Darwins principle of the survival of the fittest applies to such systems.


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Complex systems obey the basic laws of physics, but also spawn new, derived laws

that hold among the new collective modes.

In this context, Darwinian selection (see Sec. 1.5) may be thought of as a

quasi-equilibrium complex-adaptive version of dynamical energy optimization,

i.e.,efficiencydemanded bya higher-level principle of least action.

The pressure of evolution favours primitive cells that form multi-cellular sys-

tems, with some cells doing specialized tasks. We discuss vision, neurons, mem-

ory and the emergence of consciousness, intuition, feeling and sensation usually

associate with the mind of an intelligent, alert being. Here we have inputs from

neuroscience, artificial intelligence, as well as the physics of complex systems.

The energetics of complex proteins, their essentially non-computable conforma-tions, and the indeterminacy and decoherence arising from the ambient environ-

ment conspire to replace the seemingly rigid determinism of small dynamical sys-

tems by the very opposite of determinism (see Sec. 8.6). That is, we begin to

understand the existence of conscious machines which are largely biological au-

tomatons, but having a margin of free will and a capacity for strategy and action

based on their perceptions. However, this direct physico-chemical approach of

the hard-headed scientist is assailed from many angles, as discussed in the next

section.

1.4 The direct approach and its modern critics

If we leave the mystics and obscurantists to themselves, we have more subtle crit-

ics who question the very method and validity of the search for understanding.

In fact, science studies, or inquiries into the nature of sciences, have become a

popular component of the non-science part of academia today. When Feyerabend

[72]concludes that there is no discernible method in science, and that anythinggoes, he began as a critic of the efforts of philosophers of science to describe and

define the scientific method. But the criticism is in fact leveled against any type of

claim to understanding, be it in the sciences or the humanities.

Scholars armed with case studies from the history of science would present

multi-faceted arguments claiming that science is itself a result of social paradigms

or personal dispositions, with little or no basis in reality, and no better than the

folk lore which worked very well for the needs of a previous era. And yet, even the

very air we breath is air-conditioned by the technological fruits of science. These

same scholars would not hesitate to use airplanes, computers, or other products of

this very doubtful enterprise.


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qualia etc., would be claimed to be even more beyond reductionism. The appeal

to holism is not at all new, and goes back to antiquity.

The author of theSuthra-kritange, a Sanskrit text going back to Upanishadic times, perhaps fiveor six centuries before Christ, explains consciousness as an emergent property which manifests itself

when the elements come together in the body, like the intoxicating power when the ingredients aremixed [116].

An alternative view is that the whole is never more than its parts inclusive of

the interactions and boundary conditions defining the system! Given the parts,

the actual physical realization of the whole is the bottom-up process of building a

complex system. This is usually a selectiveunification of one possible combina-

tion of the parts, assuming that we even know how to enumerate the componentparts. In fact, when we study the quantum theory of entangled systems, we learn

that knowledge of a part can dictate the very nature of the whole, and vice versa. In

effect, given the interdependence of the components and the whole implied by

reductionists and anti-reductionists alike, it should not matter what picture we use

unless the specification is incomplete! In our view, the error of much past think-

ing lies in how the parts (which make up the whole) are counted and boundary

conditions are listed. Can we even list the components?

If we consider H2O, it obviously has H, O, and H atoms, further specifiedas nuclei and electrons. We need not go beyond that level of reduction if the en-

ergy range is specified to be those of molecules. What is often forgotten is that

there are interacting fields among these particles, as well as boundary conditions

defining the extent of the system. Bohmian mechanics or density functional theory

incorporate these in the quantum potentials, Kohn-Sham potentials etc., acting

on the particles. Interactions are mediated by field particles which are, in this

case, Coulomb interactions (mediated by longitudinal photons). It is only when

these are included with the atoms that all the parts of the initial system could beconsidered to have been counted if they could even be counted! Even then the

story is not complete. The specification of the parts has to include a description

of the initial state of the component parts. The water molecules, i.e., the whole,

are a specific selection from the many possibilities that one may construct from

the initial parts (other possibilities are, e.g., an ionized plasma, a metastable H+,

OH system, etc., depending on the total energy). All the properties of the water

molecule can be predicted to the precision needed in chemistry or physics, and

both the reduction process, as well as the reassembly process can be executedwithin quantum chemistry, up to the required level of molecular complexity.

However, is there a non-physics approach with better predictive power? Even

if some properties of water are deemed emergent, they are fully accounted for


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in every detail. What about the wetness of water? This is a property of the joint

system consisting of the sample of water and the observers tactile organs taken

together. Can we then extend this reasoning to cover the observer? What about

properties like consciousness, thought, volition and life itself? Already in 1890

Thomas Huxley[112]asked the same questions and gave the correct answers:

When hydrogen and oxygen are mixed in a certain proportion, and an electric spark is passed

through them, they disappear and a quantity of water . . . appears in their place. . . . we do not hesitateto believe that . . . (the properties of water) result from the properties of the component elements of thewater. We do not assume that a something called aqueosity entered into . . . the oxide of hydrogen . . .

On the contrary, we live with the hope that . . . we shall by and by be able to see our way clearly fromthe constituents of water to the properties of water., as we are now able to deduce the operations of a

watch from its parts and the manner . . . they are put together. Is the case in any way changed whencarbonic acid, water and ammonium disappear, and in their place, under the influence of a pre-existing

living protoplasm, an equivalent weight of the matter of life makes its appearance? . . . What better . . .status has vitality than aqueosity? . . .

It is precisely this determinism of all properties, vis vitalisor not, that is

thought to be implicit in this reductionist scheme that many dislike. If physics

is to govern everything, and if we can predict everything with machine preci-

sion, are we all clock-work mechanisms contained in a universe, which is it-

self dictated by the same set of unrelenting physical laws? Are we claiming that

the physics of the Big bangcompletely determined the actions of hijackers who

rammed a jet plane into the World Trade Center on 9/11? Is there, in effect no fun-

damental difference between an intelligent human being, a brainwashed human

being, and a properly programmed supercomputer?

The aversion to a complete laws-of-physics description (LPD) of the phys-

ical, biological and human realms arises not only in the context of human de-

terminism and free will, but already in the application of LPD to organic, living,

conscious creatures and personal pets. We hope to show that the possibilities con-tained in the laws of physics stretch beyond our best imagination. It turns out that

the properties of any real system have indeterminacies built into them, whatever

the length scale or time scale, be it in the quantum limit or in the classical limit.

This does not essentially depend on Heisenbergs uncertainty principle, quantum

measurement theory, chaos theory and so forth, although all these contribute to

the escape from rigid physical determinism at each length scale. In our view,

rigid determinism is a special property offinite few-particle dynamical systems.

The many-body problem of the real world has just the richness andcomplexityweneed to resolve this issue (e.g., see Ch. 8 or Ch. 14).

Let us now return to the great program of reductionism initiated by the an-

cients. The Greek atomists had already understood the importance of move-

ment and reached a reductionist, if poetic, world view which may have achieved


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dominance if not for the rise of Christianity wrapped in Aristotelianism. When

Galileo published hisDiscourse on Two New Sciences [78] in 1638, after his earlier

work on Two world systems, he returned to the study of motion within a conceptual

framework rooted in the tradition of Democritus, Aristarchus and Archimedes. In

contrast, the Aristotelian approach was to assimilate inanimate motion into those

of living things having an end purpose,a teleology. Thus the application of a re-

ductionist program for physics, initiated by Galileo in the 17th century was indeed

the resurrection of a bold step.

William Harvey, a graduate of the University of Padua in 1602, worked in

England on the circulation of blood and cleared up much metaphysics in his work

De Motu Cordis. In this he resorted to studies on animals, snails and evenfi

sh,implicitly granting the unity of the tree of life. A more extreme step would be

to reduce the physiology of the brain to a science which is not based on a doctrine

of the soul. In 1664 Thomas Willis[229]published hisAnatomy of the Brain, and

followed it up withCerebral Pathology and Two Discourses Concerning the Soul

of Brutes, where he discussed psychological disorders. Unlike Galileos celebrated

work, well enshrined in subsequent philosophical and scientific thought, Williss

work is not well known outside the scientific community. Nevertheless, modern-

day attempts to describe human consciousness, brain function and physiology inchemical terms have to be viewed as a continuation of the reductionist program

of Willis, an associate of Robert Boyle who was also at Oxford.

1.5 Evolution, and human questions

In this section we glance at a number of topics that begin in biology and fall within

several humanistic disciplines. They achieve a consiliencewithin the Darwinian

evolutionary picture. This Darwinian picture is not universally appreciated, andhence we review it briefly, noting that some of the salient topics would be taken

up again in Part-II of the book.

1.5.1 Evolution as a physical process

Darwins principle of natural selection [53] is usually viewed as an additional

non-physics principle, which is needed to describe the evolution of complex

systems (see, discussions in, e.g., Dennett [55]). It is the great unifying principleof the life sciences. However, the usual statements of the principle of natural

selection appear subjective, creating intense debate even among Darwinists.

What is natural selection? Pittendrigh calls it Darwins demon [164]. The

critique of hard adaptationist Darwinism by Gould and Lewontin in their well


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known Spandrels of St. Marco article [90], and the opposing points of view ex-

pressed by Dawkins[54], Dennett[55] and others serve to illustrate the problem

of pinning down what natural selection is about. In effect, if natural selection

is summarized by, for example, the survival of the fittest dictum, we cannot de-

fine the fittest as those animals that survive. In effect, as Ernst Mayr [140]had

noted, many adaptationist discussions can sound like glib historical narratives,

just-so stories, or Freudian accounts of dream interpretation. Sometimes it may

be written in the fancier jargon of fitness landscapes and other elaborations. This

emphasizes the need for a better analytical and physical discussion. In fact, some

researchers like Stuart Kauffman have looked for ways of rephrasing Darwinian

evolution in terms of self-organization and off-equilibrium dynamics[120].It is quite likely that the principle of natural selection can be economically

and usefully expressed in terms of other fundamental variational principles, which

apply to all physical systems. The principle that the whole system evolves towards

a state of lower free energy includes the possibility that some parts of the system

decrease their entropy while other parts increase much more. When a system is

driven, we have the principle that all processes occur so as to minimize the amount

of action consistent with the applied set of constraints and energy inputs. This is

the principle of least action. The evolutionary process may be viewed as a Monte-Carlo type simulation of a system of movers in a landscape, and held at some

temperature and other environmental parameters that change slowly. Here the ac-

tion principle comes in via a move-selection scheme, as in Verlets algorithm or

that of Metropolis and Teller (see Sec. 2.4.7) [145]. In fact, modern quantitative

biology has already adopted many of these ideas from condensed-matter simula-

tions into the domain of soft condensed matter and biology. Within such simula-

tions of driven systems, it is possible to show that complex organisms evolve from

random initial states, as proposed in Darwinian evolution.A crystal formation is an organized complex, but it is an equilibrium struc-

ture. Its capacity to replicate is instructive but uninteresting. The various possible

crystal phases are described by the phase diagram of the material. This phase di-

agram becomes extremely rich and complex when we consider non-equilibrium

situations and multi-component dissipative phases. Living organisms belong to

this extended, dissipative part of the non-equilibrium phase diagram. A soap

bubble is a rather simple non-equilibrium dissipative system which is in quasi-

equilibrium for the short life-time b of the bubble. It forms using the energyof the air-water interface; it lasts for b seconds and then decays as the ambi-

ent parameters change to a non-equilibrium regime. Living organisms are such

dissipative systems, though more complex and also adaptive. They too obey vari-

ational principles giving a direction to the process of evolution. This gets us out


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of the paradox where evolution is generally thought of as a completely unguided,

blind process, while optimizing the fitness of whatever is evolving. We may

even picture the unfolding of the universe from the big bang as a Cosmic Simula-

tion guided by a weight function which does the appropriate natural selection at

each step. The weight function ensures that an effective free energy and an effec-

tive action are minimized, subject to various boundary conditions. Adaptation

is the biologists term for what the physicist calls the response of the system to

the external perturbation; this response provides the accommodation of the vari-

ational principles within the energy and time scales of the problem. Furthermore,

the stability of certain evolutionary species for certain lengths of time requires the

concurrence of a suitable set of time scales (damping times) in the characteristsics(normal modes) of the total system, as discussed in Sec. 2.3.6.

Looking at evolution in this way helps to explain why nature seems to be

so wasteful. Why does nature have to sow millions of seed to germinate only a

few grains? Why produce millions of sperm only to hatch a few Salmon, or churn

out millions of galaxies and stars for no apparent purpose? They are all necessary

configurations required to evolve towards the answer in a giant simulation. In

fact, the bigger the number of configurations sampled, the more accurate is the

answer, in the sense of better satisfying variational principles!

1.5.2 Existential and social questions

This brings us to existentialist questions that we deal with in the last chapter of the

book. Why are we here, what is our purpose and destiny etc.? One might even dis-

miss such questions as meaningless, following the modern positivists or the early

Buddhists of the 6th century B.C. According to H. H. Price [173], we have to

reach Cambridge of the 1920s with its positivist philosophers to encounter such apoint of view. Positivists dismiss experimentally untestable questions as meaning-

less just as questions about the sex of the triangle ABC have no meaning,

even though syntactically correct. However, unlike in ancient times, many ques-

tions about our cosmological origins, consciousness and future destiny can be

examined within the laws of physics.

We mention the early Buddhists or Gnostics to emphasize that human destiny,

morality, human suffering and salvation are traditionally the terrain of religious

and philosophical thought.While many science-oriented readers may dismiss suchreligious and philosophical thought as antiquated, their enormous cultural pres-

ence cannot be ignored. They are an empirical social fact. In every civilization, be

it Chinese, Indian, or European, there were thinkers who were primarily scientific,

and others who were primarily religious. A figure like Plato straddled both camps,


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and owed much to the religion of Bacchus and the tradition of Orpheus. Plato was

the source of later developments that came to be embodied in Christian theology.

Hence we have not hesitated to reach into the insights and points of view that may

come from such sources.

Hellanic rationalism and Christian mysticism could be reconciled in the idea

that the world is a product of intelligent design. William Paley [153], writing in

1802, was one of the clear proponents of intelligent design (ID). Paley discussed

ordinary mechanical clocks that are utterly simple in comparison to those pro-

duced by the evolutionary process. In Paleys Natural Theology: Or Evidence of

the Existence and Attributes of the Deityhe argued that the elaborate complexity

of nature is clear evidence for an intelligent creator. Darwin tacitly accepted thispoint of view before he set off on the voyage of discovery on the Beagle. Paley,

in the introduction to his book brought up the analogy of the watch. Suppose one

happened to find a watch on the ground. Would not its intricate mechanism imply

that the watch must have had a maker . . . who comprehends its construction, and

designed its use? The intricate working of the natural world was vastly more im-

pressive than any watch. Paley could not see it to be anything but the product of

a supernatural being acting with conscious intent. This is the argument based on

Intelligent Design that has been resurrected in more recent times by the religiousapologists. It has been embellished with new clothing by creationists as a counter

to the teaching of evolution in American schools [20]. However, it should be re-

marked that Intelligent Design and natural theology were a great advance over

the thinking based on purely capricious divine wrath that preceded them. Even

mountain formations were regarded as punishment dealt to earth by a creator who

was angered by the misbehavior of the humans he had created. It was Sir Charles

Lyell, the geologist who preceded Charles Darwin, who reformed such medieval

beliefs to conform to the concept ofa rationalcreator.

William Paley did not know about circadian clocks that are products of evolution and well suitedto the needs of living systems. Circadian clocks are the biological time keepers of metabolic and be-

havioral activity which relate to the cycle of day and night, seasons [164]and latitude. They are tem-perature compensated biological clocks found in mammals, flies, plants fungi and even cyano-bacterial

colonies! These clocks depend on bio-chemical feedback loops associated with cellular transcriptionregulators. Every protein activity seen in the feedback loops used in the fruit fly is also present in themammalian clocks[51], testifying to their evolutionary kinship. The daily flux of photons, made up of

visible light as well as infra-red heat provided an additional window for organisms that learned to timetheir chemical activity in an advantageous manner, by evolving an internal clock.

A modern form of Intelligent Design contends that the universe exists for

producing the Human species, and that there are strong signatures of this revealed

in otherwise unexplainable coincidences in physical theory. Brandon Carter in

1974 [43]called this theAnthropic principle, a type of argument for design[15].


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In essence, this is a theory without predictive power, but has a capacity to say all

this is too much of a coincidence, it must have been designed to be so. If the

electron did not have a spin, the periodic table of elements would not be as we

know it, ergo, there would not be any carbon, and carbon-based covalent bonds

are not possible, and we wouldnt be here. If carbon did not have a nuclear energy

state at about 7 MeV, then Carbon would not have been produced in the stellar nu-

clear reactions that produce solar energy. Then there would be no carbon ergo,

we wouldnt be here. All these surely indicate that the great designer thought of us

and made sure that electrons are half-spin particles, and arranged that carbon had

the right energy states! This type of argument is a modern version of Rev. William

Paleys old arguments (1802) about the marvelous mechanism of nature. The cre-ationists[192,76]seek to find unexplainable, awe-inspiring mysteries in a world

whereManis the central fact. They unfortunately ignore the vast amount of Dark

Energy and Dark Matter that seem to be irrelevant to the anthropic principle.

Weinberg [218]has proposed a simple possibility where theology has been

replaced by the usual picture of the uneconomical working of Nature that sows

millions of seeds to sprout a few progeny. Our part of the universe is regarded as a

tiny speck in a super-universe containing all possible types of universes. Life as we

know it appears in some rare parts of the super-universe where the cosmologicalconstant and all other physical parameters are in the right range. We happen to be

in it and the anthropic principle becomes an empty statement.

Is there a concept of good and bad in the Universe? Clearly, nature stated

in physics terms isvalue neutral, as further discussed in Sec. 2.1.1. This point of

view is, however, not universal, even among physicists.

Christian rationalists, Buddhist or Jain epistemologists started from very dif-

ferent assumptions. Early Buddhists claimed that the external world is a sequence

of mental and physical events (Nama, Rupa) concatenated by laws of causation.Cosmological or mind-body questions were deemed metaphysical, and such in-

quiry was discouraged (see Sec. 2.1). However, they postulated transcendental

laws that were distinct from physical law. One such transcendental law admitted

by these ancient thinkers was a moral law, based on fate, or the more complex

concept ofKarma. Fate was also a fundamental tenet of Greek belief. Similarly,

the rational theologies of Judeo-Christian traditions also invoke a moral law, al-

though founded in an act of mystic faith flowing from a personally addressable

God, some sacrificial act or eschatological event. However, in traditional Chris-tianity, every one, even a new-born infant, is considered wicked. Individuals are

elected to the city of God only by the grace of God not because they lead a

good and virtuous life. Anthony Burgesss novel A clockwork Orangeand Stan-

ley Kubricks film feature the errant adolescent Alex; they explore the conflicting


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views of Saint Augustine and Pelagus on the notion of Original Sin and the free-

dom to chose good or evil[159]. The view that living virtuously by our own moral

choice would get us to heaven is known as thePelagian heresy. The Council of

Orange and other subsequent authorities crushed this heresy.

In modern times, the noted cosmologist George Ellis has writtenOn the moral

nature of the Universe [151]. Similarly, various dialectical types of reasoning,

be they in the hands of Hegelians, materialists or humanist thinkers, sometimes

imply an agenda based on moral objectives. Unfortunately, there does not seem

to be any justification by way of physical law, or empirical evidence, for any such

moral laws or punitive fate permeating the processes that occur in our world.

In fact, the pain, misery and patent injustice (evil) prevalent in the world couldequally well be used as a basis for a belief in a malevolent creator. This point of

view, held by the adherents of Catharism, and persecuted by the Inquisition as a

heresy, has found a modern idiom in popular movies like the Matrix, where the

world is just a dream sequence controlled by an evil computer.

1.5.3 Exorcising the soul and inducting new notions

We noted how some physicists, intrigued by the enormousnumber of steps neededto create life from the basic particles, and the low probability of many such steps,

gave up the intellectual endeavor in favour of a quick solution. This is couched in

anthropic principles and metaphysical explanations. The soul is of course the

most famous example of giving a distinctive spiritual character to matter. The

Sanskrit word jeeva(life spirit) was probably the etymological source of Eve,

whileom, orathman(soul) in Sanskrit, may have been the progenitor of the name

Adam. It has survived in modern German as atmen (breath).

During Buddhist times (6th century BCE), Indian materialists (Lokayathas) like Payasi hadactually attempted to detect the existence of a soul by weighing a man immediately before and after

his death. Confusingly, the corpse could be heavier than the living body!

While the idea of a persisting soul was fundamental to Hebrew, Hindu and

Orphic belief systems, some ancient thinkers like Confucius had no use for the

concept of a soul. The Buddhists (and some Jains) had developed detailed theo-

ries of the world as being made up of impermanent streams of mental and physical

events, ornamaandroopa. The Buddha in the 6th century BCE explicitly rejected

the doctrine of an enduring soul (aathma), and proposed the doctrine ofanattaor

anathma, i.e., non existence of an enduring soul or self. Nevertheless, most In-

dian thinkers re-introduced a consciousness which goes from one life to another

in a cycle of rebirths, although ever changing, and also carrying long individual-

ized concatenations of Karma. Remarkably, most thinkers, be they of the East


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or West, have ignored the dual parentage of every child, merging two identities

of mother and father in the off-spring. Interestingly, there has been no religious

teaching where the childs soul is proposed to be a hybrid of those of the two

parents.

This old battle regarding the soul could be the new frontier of contention be-

tween science and religion in the 21st century, just as geocentrism was to the

renaissance, and Darwinian evolution was to the 19th and 20th centuries. As neu-

roscience advances, comprehending human personality falls within the realm of

physics and chemistry. The ghost in the machine of Gilbert Ryle[185]is found

to be analyzable and explainable in terms of brain function. This first became clear

in thefi

eld of motor control of perception[118]; but today, brain processes con-trolling personality are regarded as cardinal aspects of personhood. So then, why

do we need a ghost in the machine at all? Although such views have been very

common among scientists, it is also gaining ground among philosophers who have

begun to look at consciousness in tandem with experimental research[146].

Does that mean that there is no identity of a person? The first property that

defines the identity of a person is the encoding of information in his/her DNA

genomics. This is complemented by a knowledge of folded protein-structure,

cells, neurons and the map of acquired traits whose physio-chemical descriptionis the work of current research in neuroscience. The effective length of the DNA

in terms of its binary bit length (see Secs. 2.3.5, 12.6.2) is a rough measure of

the complexityof a living organism viewed as a complex adaptive system. The

DNA determines the proteins and they in turn form the organism. However, the

detailed three-dimensional structure of a protein (the conformation) is subject to

the ambient force fields. Given that we are currently unable to even specify the full

conformational details of a single protein molecule at room temperature, we are

clearly unable to predict its time evolution at the level of detailed conformations.We will never be able to produce two identical brains!

This inability to synthesize or predict is not a refutation of the physical model,

but an affirmation of the physics of complex systems and chaotic dynamics that

applies under suitable circumstances even to hard-sphere billiard balls (see

Sec. 8.6)! Thus new notions, coming from information science and the theory of

complex systems may provide scientifically sound alternatives to old metaphysical

concepts, and also define the limits to our knowledge.

the physics of the mind

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