How well has Hume’s psychology of causation

withstood the test of time?

The plan

1 Introduction2 Hume’s psychology of causation3 Causal perception4 Causal inference and associative

learning5 Causal inference and causal

perception6 Innateness

1 IntroductionHume way more interested in the psychology of causation than the metaphysics and semantics.

Doing the ‘science of man’.

(Actually main target is epistemological, but he thinks – wrongly – that the psychology has a bearing on this.)

2 Hume’s psychology of causation

Starter question:How do we get to have beliefs?(where ‘belief’ = expectation)

Aim: to find a psychological mechanism which delivers belief as output, but does not have belief as input.

Input must be impressions/ideas/knowledge, since we already know how they arise.

Answer: ‘Custom or habit’ or ‘A-mechanism’(‘A’ for ‘associative’)

2 Hume’s psychology of causationWhat’s wrong with this account (UP)?

(P1) c occurs

(P2) C’s have been constantly conjoined with E’s in my past experience

(P3) Instances which I haven’t experienced resemble those I have experienced (Uniformity Principle)

(C) e will occur.

Answer: (P3) is itself a belief, so can’t be input to a mechanism that explains the origin of belief in general.

2 Hume’s psychology of causationHume’s account (the A-mechanism)

(P1) c occurs

(C) e will occur

Input: present impression (P1)Output: beliefMechanism: habit or custom

Mechanism activated when past C’s have been conjoined in my experience with past E’s (memory).This explanation of belief is not circular: it does not have belief as input. Job done!

2 Hume’s psychology of causationNext up: causal perception & inference (A-

mechanism again)

Quote …

I claim:► The impression of NC gives us genuine causal

experience (or ‘perception’ in psych terms).

In ‘single instances of the operation of bodies’, all events ‘seem entirely loose and separate’. Not when the A-mechanism is up and running!

► Causal judgement involves the idea of NC.

So the A-mechanism delivers (a) expectations, (b) causal perception, (c) causal judgements.

The A-mechanism

idea of NCexpectation (e) impression

of NC

Past experience + present impression of c

HABIT

JUDEMENT:c caused e

PERCEPTION:c causing e

2 Hume’s psychology of causationThat was all causation ‘considered as a natural

relation’.

Finally: Conscious causal inference (C-mechanism: causation as a ‘philosophical relation’).

Not immediate/instinctive; involves conscious reasoning.

E.g. inference about what C causes using evidence not involving C.Coffee (C) + cake (B) = wide awake (in past exp)Cake alone = zzzzz (in past exp) Coffee causes being wide awake(Every event has a cause; isn’t cake; so must be coffee.)

Only beings with A-mechanism can have C-mechanism (else no beliefs possible; also no idea of NC).

But can have A-mechanism without C-mechanism (dogs)

2 Hume’s psychology of causationConsequences:

(a) There IS such a thing as causal perception

(b) 2 mechanisms responsible for causal inference

(A and C: A instinctive/immediate, C involves extra cognitive ability)

(c) Causal perception (sometimes) separable from causal inference (thanks to C-mechanism)

(d) Neither perception nor inference innate

(Past experience of regularity required)

3 Perception of causationThere is such a thing, for Hume.

Surprise!

Philosophers: ‘all events seem entirely loose and separate’ (forgetting the surrounding text)

Psychologists: Michotte’s take (existence of causal impression refutes Hume) is standard (cf. Danks).

(Ambiguity of ‘perception’ doesn’t help here. No perception of causation in philosophers’ sense.)

Hume seems to have got this bit right!

3 Perception of causationQuestion is not:

Do we perceive causation? (in psych sense), butWhat’s the mechanism?

And in particular:Can we have CP in the absence of past experience of regularity?

Jury’s out. Hard to get evidence!

Saxe and Carey (2006): ‘by the time experimentalists can find robust evidence of causal perception, infants have already had six months of experience observing causal interactions’

Hume still in the running on this.

4 Causal inference & associative learning

A-mechanism pretty crudely Pavlovian, but associative learning still generally thought to play a role in causal inference.

But seems not to be the whole story.

Blicket detector/backward blocking:(a) A + B = music plays

A alone = music playsvs.

(b) A + B = music playsA alone = music doesn’t play.

Is B a blicket? Different answers to (a) and (b).Hume doesn’t have a specific story here, but he does have an additional mechanism for causal inference (association not the only route to causal inference).

5 Causal inference & causal perception

What’s the connection? Same mechanism or distinct?One a subset of the other?One necessary for the other?

Under-explored. One way to answer it: try to find situations that prompt only causal perception or only causal inference.

Schlottmann & Shanks (1992) get this result.

Compatible with Hume (if cut some slack):A-mechanism: delivers causal perception (& inference). IrresistableC-mechanism: can override A-mech inference, but not perception (too late!).

6 InnatenessBig challenge to Hume (though jury out):

Perhaps (some) causal perception & inference is innate.

Maybe don’t need past experience to get:► (some) CP (launching event)► (some) causal inference (born with assumptions

about causal structure).

But …Hume’s scruples re innateness are (mistakenly) based on epistemological scruples re rationalism.

He could accept some innateness without weakening his arguments against causal rationalism.

Maybe he should have done (but hardly his fault) …

6 InnatenessHume’s thesis:

A priori knowledge of the causal structure of the world is impossible.

Standard early modern view:Innate = a priori.If belief that p is innate, then p is known a priori.

So Hume thinks he needs to hold that causal inference (and so perception) is acquired, not innate.

But he doesn’t! Confuses genesis of belief with justification:

► We can learn p through experience yet p have a priori justification (1 + 2 = 3).

► We can have innate belief’ that p, yet p be justifiable only a posteriori.

6 Innateness“As this operation of the mind, by which we infer like effects from like causes, and vice versa, is so essential to the subsistence of all human creatures, it is not probable, that it could be trusted to the fallacious deductions of our reason, which is slow in its operations; appears not, in any degree, during the first years of infancy; and at best is, in every age and period of human life, extremely liable to error and mistake. It is more conformable to the ordinary wisdom of nature to secure so necessary an act of the mind, by some instinct or mechanical tendency, which may be infallible in its operations, may discover itself at the first appearance of life and thought, and may be independent of all the laboured deductions of the understanding.”

If the ability to infer like effects from like causes were innate (pre-programmed expectations; no experience necessary), that would be even more conformable to the wisdom of nature!

(Though if the ‘idea’ of causation were innate, e.g. born with assumptions about causal structure (and not just pre-programmed expectations), that would rather undermine his entire account ...)

ConclusionGiven that Hume:► was writing more than 250 years ago, and► deployed a really dubious scientific method (viz,

introspection),

he did a pretty good job with the psychology of causation!

► Right about causal perception► At least partly right about the role of associative

learning► At least partly right about the relationship between

causal inference & perception.

(Though might be wrong about innateness …)

Not bad!