The Scandal of Philosophy

The Problem Stated

Suffice it to say, not everyone has approved of Hume’s account of scientific theory.  So messy, so human, so fallible.  The counterargument is nearly always the same; the Scientific Method is able to deliver unassailable facts that can then be used as the basis for deducing other certainties.  The problem with this argument is also nearly always the same: The Scientific Method does not exist.  Peter Medawar (1969), who won a Nobel prize in medicine, put it this way:

Ask a scientist what he conceives the scientific method to be, and he will adopt an expression that is at once solemn and shifty-eyed: solemn, because he feels he ought to declare an opinion; shifty eyed, because he is wondering how to conceal the fact that he has nothing to declare. 

Medawar also notes that even though scientists have no method that they follow themselves, they generally do not mind in the least “deploring the utterly unscientific way in which everyone else carries on – politicians, educationalists, administrators, sociologists – and it is upon them that they urge the adoption of the scientific method, whatever it may be”.  That may sound scandalous, and yes, it can be.

However, although the promise of certainty is hopeless, science does have a methodology.  It may not be codified, it may not be unique to science, and it may be a collection of methods, rather than a single method.  Furthermore, as Medawar points out, the methodological mix may vary across scientific disciplines.  For example, the methodology of physics may not be entirely transferable to biology.   But still, scientific methodology works very, very well at least some of the time – whatever it may be.  Nonetheless; science does not deliver certainty.

The Logic of Truth

Well, even if certainties cannot be had, perhaps the next best thing would be to at least use mathematics to calculate some probabilities.  But, that has never worked very well either.  For example, after acknowledging the difference between probability based on frequency and that what he and Keynes (1921) called logical probability, FP Ramsey (1926) criticized Keynes for not acknowledging a fundamental difference between the “Logic of Consistency” and the “Logic of Truth”:

Logic as the science of argument and inference is traditionally and rightly divided into deductive and inductive; but the difference and relation between these two divisions of the subject can be conceived in extremely different ways. According to Mr Keynes valid deductive and inductive arguments are fundamentally alike; both are justified by logical relations between premiss and conclusion which differ only in degree. This position, as I have already explained, I cannot accept. I do not see what these inconclusive logical relations can be or how they can justify partial beliefs.

So, after agreeing Hume that inductive arguments cannot be equated with deductive logic (i.e. Relations of Ideas), Ramsey offers this view:

We are all convinced by inductive arguments, and our conviction is reasonable because the world is so constituted that inductive arguments lead on the whole to true opinions. We are not, therefore, able to help trusting induction, nor if we could help it do we see any reason why we should, because we believe it to be a reliable process. It is true that if anyone has not the habit of induction, we cannot prove to him that he is wrong; but there is nothing peculiar in that. If a man doubts his memory or his perception we cannot prove to him that they are trustworthy; to ask for such a thing to be proved is to cry for the moon, and the same is true of induction. It is one of the ultimate sources of knowledge just as memory is: no one regards it as a scandal to philosophy that there is no proof that the world did not begin two minutes ago and that all our memories are not illusory.

So, what does that tell us about induction?  Not very much, really.  But, there is one thing: A good inductive argument is a convincing one.  Quantify that.

Probability as Gradation of Provability

More recently, LJ Cohen made a career out of writing about the other probability.  He traced the practice of assigning weights to competing theories to Francis Bacon (Cohen, 1980).  He agreed with Keynes (1921) that the evidential weight for a theory is distinct from its probability (Cohen, 1989).  For example, the probability of a theory being correct may be high even with low evidential weight iff its competitors all have an even lower weight. 

Perhaps his most noteworthy observation lay in the suggestion that to objectify model uncertainty, the problem may be seen in two different ways (Cohen, 1977).  In the first view, the problem lies in defining model uncertainty in such a way that it can be quantified mathematically, thereby allowing to be placed on the same scale as statistical probability.  This is what is more commonly known as the Bayesian approach to model uncertainty, where various strategies are employed to stuff ‘prior’ scientific uncertainty into a mathematical mold.  In the second view, the problem is defined more operationally, where even though the method may arrive at a quantitative probability or evidential weight, that method may not involve mathematics.  With this view of things, marshalling the Weight of the Evidence for a theory is analogous to a legal argument: Evidence may be brought forth to either support the credibility of one theory or to reduce the credibility of a competitor. 

However, Cohen never offers much in the way of advice as to how a convincing argument for a theory is to be constructed.  Perhaps the reason is this: Once an argument becomes convincing, it is called science rather than philosophy.

References

Cohen, L.J. (1977).  The Probable and the Provable.  Oxford: Clarendon Press.

Cohen, L.J. (1980).  ‘Some Historical Remarks on the Baconian Conception of Probability’, J History Ideas 41:219-231.

Cohen, L.J. (1989).  An Introduction to the Philosophy of Probability and Induction. Oxford: Clarendon Press.

Keynes, J.M. (1921).  A Treatise on Probability. London: Macmillan.

Medawar, P (1969).  Induction and intuition in scientific thought.  In: Pluto’s Republic, Oxford Univeristy Press.

Ramsey FP (1926).  ‘Truth and Probability’.  In: Philosophical Papers, DH Mellor (ed.), 1990. Cambridge: Cambridge University Press, pp 52-109. 

Official Post Soundtrack

Beck, Jeff  (1966).  The Shapes of Things  In: Truth, Track 1

Post Notes

This is the second thesis post.  Like the first, it is also philosophical.  There may be one or two more philosophy essays later, but I'm going to climb up a Hill next.