No Such Thing as a Rational Belief

June 28, 2013


“Hume’s philosophy, whether true or false, represents the bankruptcy of eighteenth-century reasonableness. He starts out, like Locke, with the intention of being sensible and empirical, taking nothing on trust, but seeking whatever instruction is to be obtained from experience and observation. But he arrives at the disastrous conclusion that from experience and observation nothing is to be learnt.

There is no such thing as a rational belief: ‘If we believe that fire warms, or water refreshes, ’tis only because it costs us too much pains to think otherwise.’ We cannot help believing, but no belief can be grounded in reason. Nor can one line of action be more rational than another, since all alike are based upon irrational convictions. This last conclusion, however, Hume seems not to have drawn.”

The final paragraph of Russell’s chapter on Hume:

“Hume’s scepticism rests entirely upon his rejection of the principle of induction. The principle of induction, as applied to causation, says that, if A has been found very often accompanied or followed by B, and no instance is known of A not being accompanied or followed by B, then it is probable that on the next occasion on which A is observed it will be accompanied or followed by B. If the principle is to be adequate, a sufficient number of instances must make the probability not far short of certainty.

If this principle, or any other from which it can be deduced, is true, then the causal inferences which Hume rejects are valid, not indeed as giving certainty, but as giving a sufficient probability for practical purposes. If this principle is not true, every attempt to arrive at general scientific laws from particular observations is fallacious, and Hume’s scepticism is inescapable for an empiricist. The principle itself cannot, of course, without circularity, be inferred from observed uniformities, since it is required to justify any such inference. It must therefore be, or be deduced from, an independent principle not based upon experience. To this extent, Hume has proved that pure empiricism is not a sufficient basis for science.

But if this principle is admitted, everything else can proceed in accordance with the theory that all our knowledge is based upon experience. It must be granted that this is a serious departure from pure empiricism, and that those who are not empiricists may ask why, if one departure is allowed, others are to be forbidden. These, however, are questions not directly raised by Hume’s arguments. What these arguments prove – and I do not think the proof can be controverted – is, that induction is an independent logical principle, incapable of being inferred either from experience or from other logical principles, and that without this principle science is impossible.”

-Bertrand Russell “A History of Western Philosophy” (1945) Book Three, Part I, Chapter XVII, Hume, p. 672

I tempt to side with BR’s argument. Though, Hume’s skepticism has a solution. All one has to do is look to Karl Popper’s empirical falsification. Why hasn’t this method been more prominent in the scientific community?

Popper argued that science should not proceed by “induction”—that is, by finding confirming instances of a conjecture — but rather by falsifying bold, risky conjectures. Conformation is slow and never certain. By contrast, a falsification can be sudden and definitive. Moreover, it lies at the heart of the scientific method.

An example is the assertion that all swans are white. Every find of another white swan obviously confirms the theory, but there is always the possibility that a non-white swan will turn up. If this happens, the conjecture is instantly discredited. The more often a conjecture passes efforts to falsify it, Popper maintained, the greater becomes its “corroboration,” although corroboration is also uncertain and can never be quantified by degree of probability.

There are many objections to this startling claim such as many insist “corroboration” is a form of induction, and Popper has simply sneaked induction in through a back door by giving it a new name.

However, why is it though that astronomers look for signs of water on Mars or signs that Mars had water instead of undertaking efforts to falsify the conjecture that Mars never had water?

Einstein’s first cosmological model was a universe as static and unchanging as Aristotle’s. Unfortunately, the gravity of suns would make such a universe unstable. It would collapse. To prevent this, Einstein, out of thin air, proposed the bold conjecture that the universe, on its pre-atomic level, harbored a mysterious, undetected repulsive force he called the “cosmological constant.”

When it was discovered that the universe is expanding, Einstein considered his conjecture falsified. Indeed, he called it “the greatest blunder of my life.” Today, his conjecture is back in favor as a way of explaining why the universe seems to be expanding faster than it should be. Astronomers are not trying to falsify it; they are looking for confirmations.

However, I am afraid. I am very afraid of the dangers of induction. The dangers of what can be called naive rationalism. The idea that society is understandable, the systematic smoothing of the world’s jaggedness. What Taleb has called ‘sucker problems’, the black swan of things and when the things in question hold millions of livelihoods and lives in their balance sheets. It may be that the Popperian view has never been seriously been preferred because we are ingrained in the narrative. If we observed B, our limited defaults is that B must have been caused by something. A perhaps? So we look for confirmation. We can not just leave it be. We scorn the abstract!

So we take all things and put them in neat little boxes and categorize them like in a file cabinet based on our inductive narratives. What Taleb has called modernity:

We are moving into a phase of modernity marked by the lobbyist, the very, very limited liability corporation, the MBA, sucker problems, secularization (or rather reinvention of new sacred values like flags to replace altars), the tax man, fear of the boss, spending the weekend in interesting places and the workweek in a putatively less interesting one, the separation of “work” and “leisure” (though the two would look identical to someone from a wiser era), the retirement plan, argumentative intellectuals who would disagree with this definition of modernity, literal thinking, inductive inference, philosophy of science, the invention of social science, smooth surfaces, and egocentric architects.

There is a dependence on narratives, an intellectualization of actions and ventures. Public enterprises and functionaries—even employees of large corporations—can only do things that seem to fit some narrative, unlike businesses that can just follow profits, with or without a good-sounding story.

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  1. Wayne

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