Updated: 03 March 2000

EXPLANATION – beside intrinsic interest

goal of science ?

theories that have truth or high verisimilitude because they are needed for explanations

instrumentalism vs realism

Duhem - science does not explain

contemporary instrumentalism seeks account of explanation that permits explanation without truth

1.

EXPLANATION : what is it?

Answer to a “why” question.

Why did Adam eat the apple?

Why is the sky dark at night?

Dewey’s story

Why is the balloon expanding?

PRAGMATIC CONCEPT

answer depends on the context

audience - questions

information available to audience

(why does sodium turn yellow ?)

2.

specification of question

(why do you rob banks?)

apprentice robber of some naivety

ernest young social worker

supposed to give understanding

OED: explanation - “statement or

circumstance that explains”

explain: “to make clear or intelligible”

“to give understanding”

3.

? Explanation = any story that gives understanding

Real vs apparent understanding

Margaret Lawrence

The seven heavenly bodies

bizarre

add in background belief

why – God – mirror - cosmos

Philosophical theory of explanation - an account of what constitutes genuine explanation in a context.

All things being equal, we seek a single unified account

4.

Covering Law Model

Deductive-Nomological Model

Hempel’s Model

Dewey’s puzzle

In his book, How We Think, John Dewey describes a phenomenon he observed one day while washing dishes. Having removed some glass tumblers from the hot suds and placed them upside down on a plate, he noticed that soap bubbles emerged from under the tumbler’s rums, grew for a while, came to a standstill and finally receded into the tumblers.

Why did this happen? Dewey outlines an explanation to this effect: Transferring the tumblers to the plate, he had trapped cool air in them; and thus to an expansion of the soap film that had formed between the plate and the tumblers’ rims. But gradually, the glass cooled off, and so did the air inside, and as a result, the soap bubbles receded.

5.

The explanation here outlined may be regarded as an argument to the effect that the phenomenon to be explained, the explanandum phenomenon, was to be expected in virtue of certain explanatory facts. These fall into two groups: (I) particular facts and (ii) uniformities expressible by means of general laws. The first group includes facts such as these: the tumblers had been immersed in soap suds of a temperature considerably higher than that of the surrounding air; they were put, upside down, on a plate on which a puddle of soapy water had formed that provided a connecting soap film, and so on. The second group of explanatory facts would be expressed by the gas laws and by various other laws concerning the exchange of heat between bodies of different temperature, the elastic behaviour of soap bubbles, and so on. While some of these laws are only hinted at by such phrasings as ‘the warming of the trapped air led to an increase in its pressure’, and others are not referred to even in this oblique fashion, they are clearly presupposed in the claim that certain stages in the process yielded others as their results.

6.

Mill System of Logic 1843

? Newton

Received View - in empiricist tradition

uses relatively unproblematic ideas

social sciences vs natural sciences

remains point of departure for discussions of explanation

can you solve Hempel’s problems ?

See that what happened, had to happed given other things (the particular facts) because of the laws

See why it had to happen

7.

HEMPEL’S MODEL

An explanation is an argument !!!

Explanans

Initial Conditions: C1, C2,...Ck

Laws: L1,L2,...Lr

Explanadum \ E

Conditions:

1. Argument valid

2. Laws enter essentially into derivation

Potential explanation

True explanation

Attractive

unifies

explains importance - prediction

simple ideas

particular events and to laws

8.

But explanations don’t look like this !

Hempel : “models” … “a useful reminder … explanation as characterized constitute ideal types or theoretical idealizations and are not intended to reflect the manner in which working scientists actually formulate their explanatory accounts”

Elliptical Formulations

Why did the butter melt? The pan was still hot.

“an account of this kind omits mention of certain laws of particular facts which it tacitly takes for granted, and whose explicit citation would yield a complete deductive-nomological argument”

9.

Partial Formulation

explanans not detailed enough to entail the specific explanadum

more work needed

Freud explains his slip of the pen due to unconscious desire

has laws

need more detail

10.

Explanatory Sketch

Why did anyone go to Canada?

Because of the fur trade

general outline to be developed

area to look for laws

11.

Non-Pragmatic Ideal

concept of proof in mathematics

“an argument Y is a proof of a given sentence X without making any mention of persons who might take cognizance of Y”

“… constructing a nonpragmatic concept of scientific explanation - a concept which is abstracted, as it were, from the pragmatic one, and which does not require relativization with respect to questioning individuals any more than does the concept of mathematical proof.”

But is there any such thing?

Idealized audience of Nobel prize winners ?

12.

Better to acknowledge that it is pragmatic

Handle certain objections

All crows are black

Icabod is a crow

Therefore, Icabob is black

fall about laughing at poor old Hempel

Or imagine telling quantum chemistry story to school kids

13.

LSE

Logical Space of Explanation

- Hempel avoid subjectivity in explanation

All meet the conditions, pragmatic factors dictate which one it is appropriate to give

Henry the mad bird painter

14.

Statistical Inductive Explanation

smoking - lung cancer

high probability replaces proof

syphlis – paresis

15.

PROBLEMS

1The American Objection

flag pole

sky dark at night

Explanation is asymmetrical

DN Model does not guarantee this.

So not a sufficient condition for explanation.

Accidentally true generalizations do not explain.

What makes a true generalization a law?

But this is a common problem

16.

Relevance

Icabod fails to get pregnant

Sugar dissolves in holy water

DN Model fails to exclude irrelevancies.

Common Cause

barometer falls, bad weather

17.

Can it be done? Dewey’s problem again.

Dewey understood without knowing the laws. Cannot match the laws with the initial conditions.

Try to fit your favourite explanations into DN form

accept claims as explanatory without checking to see if we can transform them to DN model

Explanation by models and analogies

plate techtonics

18.

Causal Relevance

for a wide class of cases, to explain is to cite a causally relevant factor

explanations are not argument

to explain is to cite a feature of the world which is causally responsible (partially) for what you want to explain

But what is causation?

must be more than Humean regularity ?

19.

Explanation by identification

Water is H2O

Temperature is mean molecular motion

Geometrical explanations

20.

Why did DN seem so good?

Tradition of deductive presentation of knowledge

Models as idealizations

Much of physics - stipulating ideal systems (ideal gases). Derivations (if temperature goes up, so does pressure).

Understanding provided if world is sufficiently like the idealization.

Derivation confused with explanation.

Models explain by drawing attention to the causal mechanisms.

21.