The Nature of Maths

18
The Nature of Maths Maths, Certainty, and Truth, & Maths: Invention or Discovery

description

The Nature of Maths. Maths, Certainty, and Truth, & Maths: Invention or Discovery. Maths & Truth. The mathematician gazed heavenward in supplication, and then intoned, “In Scotland there exists at least one field, containing at least one sheep, at least one side of which is black .”. - PowerPoint PPT Presentation

Transcript of The Nature of Maths

Page 1: The Nature of Maths

The Nature of Maths

Maths, Certainty, and Truth, & Maths: Invention or Discovery

Page 2: The Nature of Maths

“No, no!” the physicist responded, “Some Scottish sheep are black!”

The mathematician gazed heavenward in supplication, and then intoned, “In Scotland there exists at least one field, containing at least one sheep, at least one side of which is black.”

“How interesting,” observed the astronomer, “All Scottish sheep are black!”An astronomer, a physicist, and a mathematician were holidaying in Scotland. Glancing from a train window, they observed a black sheep in the middle of a field.

Maths & Truth

Page 3: The Nature of Maths

Seeking CertaintyMathematicians build theorems based axioms that must be valid.

Late 19th century mathematicians wanted to rebuild maths from 1st principles.

The German mathematician David Hilbert led this quest for total consistency.

Page 4: The Nature of Maths

Trouble in’t millGreat strides were by mathematicians such as Gottlob Frege.

… Until Bertrand Russell thought up ‘Russell’s Paradox’

This showed a major flaw in the logic assumed up this point and questioned the existence of ‘completeness’ in maths.

Page 5: The Nature of Maths

Overcoming the insurmountable

Three decades of trying to plug the gap.

Headway appeared to be being made before Kurt Gödel proved that maths could never be logically.

Page 6: The Nature of Maths

Gödel’s Incompleteness

TheoremHis theorems paraphrase to:First theorem of undecidability

If axiomatic set theory is consistent, there exist theorems which can neither be proved or disproved.

Second theorem of undecidability

There is no constructive procedure which will prove axiomatic theorem to be consistent.(This is a simplified version of this kind of thing)

Page 7: The Nature of Maths

Huh???Everything I say is a lie.

Or:

This statement does not have any proof.

Page 8: The Nature of Maths

So???Well, nothing really...

Just as Heisenberg’s uncertainty principle in physics is largely irrelevant in everyday physics.

Gödel’s theorems do not invalidate any past proofs

They are only relevant in the logicians world of undecidability.

Few undecidable questions exist.

Page 9: The Nature of Maths

Maths, Truth, & Undecidability

Gödel’s theorems have added to the beauty and complexity of maths.

Axioms and proof still lead to absolute truth in the mathematical sense.

The discovery that maths has its limits only reaffirms that maths is a genuinely creativity set within a formalised system of logic.

Page 10: The Nature of Maths

Invention or Discovery?

In determining whether maths invented or discovered definition is everything.

That 3 sides in a right-angled obey Pythagoras’ theorem long before Pythagoras proved (invented) it.

Page 11: The Nature of Maths

Invention or Discovery?

Hippasus ‘invented’ surds with his proof of the irrationality of √2, yet every square of unit length every constructed or drawn before this had a diagonal of this length.

The Earth was the third planet from the sun for billions of years before Frege proved the existence of ‘threeness’ mathematically from 1st principles.

Page 12: The Nature of Maths

Invention or Discovery?

Newton and Leibnitz invented the calculus which is apparent any time something falls.

Bombelli invented ‘I’, the square root of -1, centuries before quantum physicists found behaviour that could only be modelled using it.

Page 13: The Nature of Maths

The real question...

It comes back to what is maths.

Much ‘maths’ has come from the observation and explanation of real-world phenomena (science).

As ‘maths’ took off in its own right, many of its discoveries have conversely been used to model and explain observations of reality.

Page 14: The Nature of Maths

My two cents:What is the sound of one hand clapping?

If a tree falls in a forest and there is no-one around to witness it, does it make any sound?

Is maths invented or discovered?

Page 15: The Nature of Maths

Clarity: Pure maths? Applied

maths?Pure maths is invented.

Applied maths is observed.

How to apply maths is discovered.

That reality can be modelled mathematically does not mean that maths is ‘out there’.

Page 16: The Nature of Maths

Definitions please.

What is Maths – what do you mean when you use the phrase?

What is Knowledge – what do you mean by knowledge?

What is truth – what do you define as truth?

Page 17: The Nature of Maths

Over to youThis is what theory of knowledge is about: getting you guys to think & actually examine the understanding that you have acquired about/within various disciplines that claim to offer knowledge.

Maths is truth, maths is beauty, maths is the only path to understanding.

The above statement may, or may not be correct.

What do you think?

...please think...

(mis)

Page 18: The Nature of Maths

Gödel’s First Theorem

To every ω-consistent recursive class κ of formulae there correspond recursive class-signs r, such that neither ν Gen r Neg(ν Gen r) belongs to Flg(κ) (where ν is the free variable of r)

Run away...