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'I have been reading with interest your book My Philosophical Development. You say on page 67 that the statement "All Greeks are mortal" cannot be proved by enumeration. ... I think that "All Greeks are mortal" can neverthless be probed by enumeration, by putting all Greeks on an island and dropping atom bombs on them for example, and that we may in fact confine our attention to thee X's that are Greeks. ...
Dear Mr Thompson, (November 14, 1964)
... The reply to your contention is that no enumeration can make certain that you have enumerated all the Greeks. There may be Greeks in the Gobi Desert descended from Alexander's army. There may be Greeks who live under ground and have never been discovered. Such possibilities are unlikely, but not impos sible. The statement 'All Greeks are mortal' may be stated as 'there is nothing which is an immortal Greek'. This is a statement about everything in the world. Your suggestion of collecting all Greeks and putting them on an island assumes there are no Greeks unknown to you. This may be true, but cannot be demon strated without a survey of the whole universe.
Source: Dear Bertrand Russell, 1969
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