Post on 04-Jun-2018
8/13/2019 Why Think Causally
1/101
Why Care AboutCounterfactual
Support?The Cognitive Uses of Causal Order
Lecture 2
8/13/2019 Why Think Causally
2/101
You Do Care About
Counterfactual
Su ort
8/13/2019 Why Think Causally
3/101
Two Regularities
All uranium spheres are less than a mile in
diameterAll gold spheres are less than a mile indiameter
8/13/2019 Why Think Causally
4/101
Two Regularities
All uranium spheres are less than a mile in
diameterAll gold spheres are less than a mile indiameter
8/13/2019 Why Think Causally
5/101
Two More Regularities
All ravens are black
All members of the 1964 GreenburySchool Board are bald
8/13/2019 Why Think Causally
6/101
Two More Regularities
All ravens are black
All members of the 1964 GreenburySchool Board are bald
8/13/2019 Why Think Causally
7/101
Conclusion
Some true generalizations are law-like;
some are notBut what is lawlikeness?
8/13/2019 Why Think Causally
8/101
Answer
A lawlike generalization supports
counterfactuals
8/13/2019 Why Think Causally
9/101
Two Counterfactuals
If these two ravens were to mate, their
offspring would be blackIf Hilary Clinton were elected to the 1964Greenbury School Board, her hair would
fall out
8/13/2019 Why Think Causally
10/101
Counterfactuals andLawlikeness
The baldness of the school board members
is a coincidence; if things had gonedifferently, baldness would not be universal
The blackness of ravens is not a
coincidence; if things had gone (somewhat)differently, blackness would still beuniversal
8/13/2019 Why Think Causally
11/101
Counterfactuals andLawlikeness
The baldness of the school board members
is a coincidence; if things had gonedifferently, baldness would not be universal
The blackness of ravens is not a
coincidence; if things had gone (somewhat)differently, blackness would still beuniversal
8/13/2019 Why Think Causally
12/101
Counterfactual Support
A generalizationAll Fs are Goffers
counterfactual support if1. Actual Fs in non-actual circumstances
would still be G
2. Non-actual Fs would be G
A matter of degree
8/13/2019 Why Think Causally
13/101
You Care AboutCounterfactual Support
If you care about the distinction between
law-like and accidental regularitiesThere are other reasons, too
8/13/2019 Why Think Causally
14/101
The Empiricist CaseAgainst Caring
8/13/2019 Why Think Causally
15/101
The Logical Empiricists
Rudolf Carnap
Hans Reichenbach
Carl Hempel
8/13/2019 Why Think Causally
16/101
8/13/2019 Why Think Causally
17/101
The Actual and the Modal
Actual fact: a fact about what happens in
the actual (even observable) worldModal fact: facts about possibilities,necessities, what might but did not happen,
what could not happen
8/13/2019 Why Think Causally
18/101
Two Positivist Theses
Only the actual is knowable
Only the actual has practical significance
8/13/2019 Why Think Causally
19/101
Only the Actual HasPractical Significance
Modal facts cannot make a difference to
our realizing the goals of science
8/13/2019 Why Think Causally
20/101
The Goals of Science
1. Explanation
2. Prediction
3. Control
8/13/2019 Why Think Causally
21/101
The Empiricist Theoryof Explanation
Hempel: To understand a phenomenon is to
be able to predict the phenomenon (atleast in retrospect)
In order to explain, learn how to predict
8/13/2019 Why Think Causally
22/101
The Goals of Science
1. Explanation
2. Prediction
3. Control
8/13/2019 Why Think Causally
23/101
The Actual and the ModalAspects of a Regularity
1. Actual: All actual ravens are actually
black2. (a) In some counterfactual
circumstances, some actual ravens
would be black(b) Some non-actual ravens, if theyexisted, would be black
8/13/2019 Why Think Causally
24/101
Prediction and Control
Are about actual outcomes
Thus they are covered by the actual part ofa regularity
Nothing else matters
In particular, the modal part does notmatter
8/13/2019 Why Think Causally
25/101
The Empiricist Position
We may care about counterfactual
supportbut we should not
Find a new definition of law-likeness
8/13/2019 Why Think Causally
26/101
Against the Empiricists
But Not Against
Empiricism
8/13/2019 Why Think Causally
27/101
My Claims
Paying attention to counterfactual facts can
make a difference to prediction and controlEven given all empiricist assumptions
Because counterfactual facts are at bottom
facts about the actual world importantfacts!
8/13/2019 Why Think Causally
28/101
Explaining Caring aboutCounterfactual Support
I will put one piece of an explanation in
place: explain practical significance ofcaring
What then must be added: evolution?
something else?
8/13/2019 Why Think Causally
29/101
Some AttemptsTo Care
8/13/2019 Why Think Causally
30/101
Two Failed Attempts toExplain Caring
1. Planning explanation
2. Induction explanation
8/13/2019 Why Think Causally
31/101
Planning Explanation
8/13/2019 Why Think Causally
32/101
Planning Explanation
Planning my actions requires counterfactual
thinking
8/13/2019 Why Think Causally
33/101
Planning Explanation
When I plan what to do, I select from
several possible actions the one that willbest realize my goal
For each action I ask: what would happen
if I were to do that?I decide by the counterfactual answers
8/13/2019 Why Think Causally
34/101
Empiricist Reply
This may be the way that humans actually
plan, but there is another way to plan thatdoes not require counterfactual thinking
8/13/2019 Why Think Causally
35/101
Empiricist Planning
Look at actual frequencies
Perform the action that most often leads tothe goal (other things being equal)
Claim: this is for practical purposes
identical to counterfactual planning
8/13/2019 Why Think Causally
36/101
Induction Explanation
8/13/2019 Why Think Causally
37/101
Induction Explanation
In order to learn the actual part of a
regularity, I must learn its modal partIf the actual part is the practical end, themodal part is the means to that end
8/13/2019 Why Think Causally
38/101
Inductive Argument
From the fact that
! All observed Fs are G
infer that
!
AllFs are
G
8/13/2019 Why Think Causally
39/101
Thesis
In order to perform this inference, you must
have reason to believe that! All observed Fs are G
is not an accident or a coincidence
So: require counterfactual knowledge
8/13/2019 Why Think Causally
40/101
Problem
The thesis is implausibly strong
A better thesis: in order to make theinference, you should lack reason tobelieve that the G-ness of observed Fs is a
coincidence
8/13/2019 Why Think Causally
41/101
The Theses Contrasted
To inferAll Fs are G, must have reasonto
believe that the G-ness of observed Fs isnot an accident
To inferAll Fs are G, must lack reasonto
believe that the G-ness of observed Fs is anaccident
O h i H C
8/13/2019 Why Think Causally
42/101
Otherwise, How CanInduction Get Started?
We cannot have reason to believe that a
pattern is not an accident until we havedone some inductive inference
8/13/2019 Why Think Causally
43/101
Lets look for something else
8/13/2019 Why Think Causally
44/101
What Is
Counterfactual
Su ort, Reall ?
8/13/2019 Why Think Causally
45/101
How Counterfactuals Work
Robert Stalnaker
David Lewis
Jonathan Bennett
8/13/2019 Why Think Causally
46/101
8/13/2019 Why Think Causally
47/101
Closest Possible Worlds?
Sounds like the truth or falsity of the
counterfactual depends on the spatialstructure of some hyper-universe full of non-actual worlds
8/13/2019 Why Think Causally
48/101
8/13/2019 Why Think Causally
49/101
World Proximity
1. Same history as actual world
2. Something in recent past goes slightlydifferently, so that pen is dropped
3. Same fundamental laws as actual world
Note that (2) implies partial exceptions to(1) and (3): make these very small
8/13/2019 Why Think Causally
50/101
Very Small
The thing that happens, so that the pen is
dropped, must1. Change as little as possible about past
history
2. Violate the laws as little as possible
8/13/2019 Why Think Causally
51/101
Putting it all together
8/13/2019 Why Think Causally
52/101
E l ti W ld f A
8/13/2019 Why Think Causally
53/101
Evaluation Worlds forA(Lewis, Bennett)
1. Same history as actual world until
shortly before occurrence ofA
2. Then there is a conservative deviationfrom actual history that brings aboutA
3. From then on, actual laws determinewhat occurs
C ti D i ti
8/13/2019 Why Think Causally
54/101
Conservative Deviation(Lewis, Bennett)
1. Happens as close toAas possible
2. Has as few side effects as possible
3. If possible, violates no laws and is nottoo improbable
4. If violation is necessary, it is discreet
8/13/2019 Why Think Causally
55/101
Restrictions
This story is correct for ordinary
counterfactuals
8/13/2019 Why Think Causally
56/101
Closest Possible Worlds?
Sounds like the truth or falsity of the
counterfactual depends on the spatialstructure of some hyper-universe full of non-actual worlds
Wrong
8/13/2019 Why Think Causally
57/101
Closest Possible Worlds
What happens in the closest worlds
depends on:1. Actual history
2. Actual laws
3. Criteria for conservative deviation
8/13/2019 Why Think Causally
58/101
Closest Possible Worlds
What makes counterfactual claims true or
false are facts about the actual worldSpecifically: Ordinary occurrent facts andfacts about laws
Empiricists are OK with both
8/13/2019 Why Think Causally
59/101
Thesis
If the facts that make a counterfactual claim
true are actual facts, then the modalaspect of a regularity is something actual
And so can make a difference even in the
empiricists sense prediction & control
8/13/2019 Why Think Causally
60/101
Question
Still, even if an interest in counterfactuals is
an interest in actual facts, whythese
actualfacts? They look like a rather arbitraryselection
8/13/2019 Why Think Causally
61/101
The Modal Aspectof a Regularity
The Actual and the Modal
8/13/2019 Why Think Causally
62/101
The Actual and the ModalAspects of a Regularity
1. Actual: All actual ravens are actuallyblack
2. (a) In some counterfactualcircumstances, some actual ravens
would be black(b) Some non-actual ravens, if theyexisted, would be black
8/13/2019 Why Think Causally
63/101
8/13/2019 Why Think Causally
64/101
All Ravens Are Black
! If these two ravens had mated, theiroffspring would have been black
! If this raven had been fed a diet ofworms, it would still have been black
8/13/2019 Why Think Causally
65/101
Some Raven Physiology
Tyrosinase helps to covert tyrosine tomelanin inside the melanosomes
Melanosomes are incorporated intofeather-producing cells
Much physical structure: bundle it togetherand call it P
8/13/2019 Why Think Causally
66/101
All Ravens Have P
That is, they all have this complicatedphysical structure that makes them black
Include in Pthe physical structure thatensures that Pis passed from parents to
offspring
8/13/2019 Why Think Causally
67/101
A Raven Counterfactual
If these two ravens had mated, theiroffspring would have been black
Find the closest worlds where the ravensmate
8/13/2019 Why Think Causally
68/101
Closest Mating Worlds
1. Same history as actual world untilshortly before mating
2. Conservative deviation brings aboutmating
3. From then on, actual laws apply
8/13/2019 Why Think Causally
69/101
Closest Mating Worlds
1. Same history, so raven parents have P
2. Deviation brings about mating conservative, so does not undermine theP-hood of the parents
3. Actual laws apply, so parentsP-hoodcauses P-hood, blackness, of offspring
8/13/2019 Why Think Causally
70/101
8/13/2019 Why Think Causally
71/101
8/13/2019 Why Think Causally
72/101
Separability
1. Physical separability: the fact of matingconsists of physical facts distinct from P
2. Causal separability: the fact of matingconsists of physical facts that are not
creating or sustaining causes ofP
8/13/2019 Why Think Causally
73/101
Contrast Case
If this raven had had some genetic defects,it still would have been black
Blackness not present in every evaluationworld because genetic defects not
separable fromP
8/13/2019 Why Think Causally
74/101
Why You Care About
Counterfactual
Su ort
8/13/2019 Why Think Causally
75/101
Overview
Regularities in the real world are very fine-grained
Knowledge of reasons for a regularityscounterfactual support provides compact
basis for knowledge of fine-graineddetails
8/13/2019 Why Think Causally
76/101
Overview
We care about regularities that offercounterfactual support because we careabout having a compact basis for learninga regularitys fine-grained details
8/13/2019 Why Think Causally
77/101
Fineness of Grain
All ravens are not black
Bleached ravensAlbino ravens
f
8/13/2019 Why Think Causally
78/101
Fineness of Grain
All ravens for which conditions Zhold, areblack
Zis very complex
Learning Zis learning fine-grained details
about a regularity
This is one-half of fineness of grain
8/13/2019 Why Think Causally
79/101
What Counterfactual Support
8/13/2019 Why Think Causally
80/101
What Counterfactual SupportDepends On
1. All actual ravens have P
2. Causal inertia of P3. Causal and physical separability of P
from relevant antecedents
4. Causal laws in virtue of which Pcausesblackness
8/13/2019 Why Think Causally
81/101
Simpler Case:Causal Antecedents
A d
8/13/2019 Why Think Causally
82/101
Antecedents
Antecedent of a generalization:All Fsare G
Antecedent of a counterfactual:IfAhad occurred, then Bwould have
occurred
8/13/2019 Why Think Causally
83/101
G d Thi K
8/13/2019 Why Think Causally
84/101
Good Things to Know
1. It is hotter above than beside a fire
2. Short term exposure may not causedamage
3. Damage more severe with length of
exposure
H T K Th
8/13/2019 Why Think Causally
85/101
How To Know Them
Dont just memorize factoids. Learn aboutmechanisms:
1. Damage comes from heat accumulation
2. Heat accumulation falls off with distance
3. Heat rises
What Counterfactual Support
8/13/2019 Why Think Causally
86/101
What Counterfactual SupportDepends On
1. All actual ravens have P
2. Causal inertia of P3. Causal and physical separability of P
from relevant antecedents
4. Causal laws in virtue of which Pcausesblackness
S i l G li i
8/13/2019 Why Think Causally
87/101
Social Generalizations
If you have more material possessions thanother people, they will tend to envy you
8/13/2019 Why Think Causally
88/101
Non-CausalAntecedents
Roasted Raven Is
8/13/2019 Why Think Causally
89/101
oas ed ave sGood to Eat
The antecedent, ravenhood, does not dothe causing
It is some physical property Pof ravens thatmakes them edible
To Know Fine-Grained
8/13/2019 Why Think Causally
90/101
wDetails
1. Learn conditions under which ravenshave P
2. Learn conditions under which Phas itscharacteristic effect (taste, nutrition)
To Know Fine-Grained
8/13/2019 Why Think Causally
91/101
Details
1. Learn conditions under which ravenshave P
2. Learn conditions under which Phas itscharacteristic effect (taste, nutrition)
Learning Fine-Grained
8/13/2019 Why Think Causally
92/101
gDetails
In conditions Z, ravens have PHow to learn Z?
Method 1: learn about the mechanism thatcauses ravens to have P
Problem: Pis unobservable
Learning Fine-Grained
8/13/2019 Why Think Causally
93/101
gDetails
Method 2: Assume that most ravens innormal circumstances have P
Worry about the final phase, where theraven is removed from normalcircumstances: killing, dressing, cooking
Do these actions interfere with P?
It All Ab t I t f
8/13/2019 Why Think Causally
94/101
Its All About Interference
What actions interfere with or undermine aravens P-hood?
Those that manipulate things that are notseparable from P
What Counterfactual Support
8/13/2019 Why Think Causally
95/101
ppDepends On
1. All actual ravens have P
2. Causal inertia of P3. Causal and physical separability of P
from relevant antecedents
4. Causal laws in virtue of which Pcausesblackness
8/13/2019 Why Think Causally
96/101
Summary
A ti
8/13/2019 Why Think Causally
97/101
Assumptions
1. All actual ravens have P
2. Causal inertia of P3. Causal and physical separability of P
from relevant antecedents
4. Causal laws in virtue of which Pcausesblackness
Source of Knowledge of Fine-
8/13/2019 Why Think Causally
98/101
gGrained Details
1. All actual ravens have P
2. Causal inertia of P3. Causal and physical separability of P
from relevant antecedents
4. Causal laws in virtue of which Pcausesblackness
C l i P t 1
8/13/2019 Why Think Causally
99/101
Conclusion, Part 1
To learn or predict fine-grained details of aregularity, learn the facts in virtue of whichit provides counterfactual support
These are actual facts that predict otheractual facts
Concl sion Part 2
8/13/2019 Why Think Causally
100/101
Conclusion, Part 2
Pay special attention to regularities thatprovide counterfactual support, becausewith these regularities, there is a compactbasis for learning fine-grained details
8/13/2019 Why Think Causally
101/101
mailto:strevens@nyu.edumailto:strevens@nyu.eduhttp://www.strevens.org/http://www.strevens.org/