Monday, 17 June 2013

Bonn, Berlin and Gettier

This month, we are fifty years on from the publication of Edmund Gettier's celebrated paper, "Is Justified True Belief Knowledge?" (Analysis, volume 23, number 6, June 1963, pages 121-123). Today, 17 June, is the sixtieth anniversary of the uprising in East Germany, which might have led to the early reunification of Germany (at least according to a broadcast on B5 radio this morning), had the Soviets not sent the tanks in.

We may also recall, for no particular calendrical reason, Bertrand Russell's note of the Gettier phenomenon, avant la lettre. The story is told in J E Littlewood, Littlewood's Miscellany, edited by Béla Bollobás, 1986, page 128. "He told me (c.1911) that he had conceived a theory that 'knowledge' was 'belief' in something which was 'true'. But he met a man who believed that the Prime Minister's name began with a B. So it did, but it was Bannerman and not Balfour as the man had supposed." [Balfour was Prime Minister from 1902 to 1905, and Bannerman from 1905 to 1908.]

Let us stick with the letter B, but move forward to the present day. Suppose that Claude, who has never lived in Germany, and whose access to German news is very limited, was taught in school, in the 1970s, that Bonn was the capital of West Germany, that West Germany was much larger, and much more significant economically, that East Germany, and that one part of Berlin was the capital of East Germany. Since then, Claude has heard of German reunification, but not of any change of capital. He reasons that the capital of Germany is probably still Bonn, but that it might have been moved somewhere else, and that if it had been moved, Berlin would have been the most likely choice.

He therefore forms the justified true belief that the name of the capital of Germany begins with a B. Does he know this?

The case is not on all fours with the Balfour-Bannerman case. Claude is aware that he might be wrong in his belief that Bonn is the capital, but reasons that even if he is, there is still a good chance that he is right in his belief that the name begins with a B. That reasoning is perfectly sound, and not just because the capital was in fact moved to Berlin. It would still have been sound reasoning, had Frankfurt or Hamburg been chosen. The problem then would have been not lack of justification for the belief that the name began with a B, but its falsity.

The reasoning would also have been sound if Bielefeld had been chosen, but then the truth of the belief that the name began with a B would have had no connection with Claude's reasoning, and we would probably have wanted to say that Claude's belief did not qualify as knowledge.

Let us return to the real world, in which the capital is moved to Berlin, Claude's reasoning is sound, and the truth of his belief that the name begins with a B is connected with his reasoning. Does he know that the name begins with a B?

It may depend on how Claude assesses the risk that the capital has moved. If he thinks there is a pretty good chance that the capital has moved, that supports a claim to knowledge, because it gives significance to the reasoning that Berlin would be the most likely new location. In giving significance to that reasoning, it also gives significance to what it is that actually makes the belief true. Claude reduces his reliance on the false lemma (that Bonn is the capital), and increases his reliance on the true lemma (that Berlin is the capital). If, on the other hand, Claude does not think it at all likely that the capital has moved, then his conscious reliance is on the false lemma, and the reasoning about the move is merely a precaution, upon which he does not expect to rely. We might then wish to deny Claude knowledge.

There is one more twist. Suppose that Claude thinks it is quite likely that the capital has moved, and that inclines us to allow him knowledge that the name begins with a B. That puts pressure on the quality of his reasoning that if the capital has moved, it has moved to Berlin. He cannot be sure of this. So unless he has good reason to think that any move would be to Berlin, with no other city in serious contention, we might not allow him to know that the name began with a B after all.

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