With regards to political enemies Plato had a kill-and-banish principle. ... In interpreting it , modern-day Platonists are clearly disturbed by it, even as they make elaborate attempts to defend Plato.

Now this principle of induction cannot be a purely logical truth like a tautology or an analytic statement. . . .

There is no history of mankind, there is only an indefinite number of histories of all kinds of aspects of human life.

Plato felt that a complete reconstruction of society's political program was needed.

Almost everyone... seems to be quite sure that the differences between the methodologies of history and of the natural sciences are vast. For, we are assured, it is well known that in the natural sciences we start from observation and proceed by induction to theory. And is it not obvious that in history we proceed very differently? Yes, I agree that we proceed very differently. But we do so in the natural sciences as well.

The old scientific ideal of episteme - of absolutely certain, demonstrable knowledge - has proved to be an idol. The demand for scientific objectivity makes it inevitable that every scientific statement must remain tentative for ever.

It is clear that everybody interested in science must be interested in world 3 objects. A physical scientist, to start with, may be interested mainly in world 1 objects--say crystals and X-rays. But very soon he must realize how much depends on our interpretation of the facts, that is, on our theories, and so on world 3 objects. Similarly, a historian of science, or a philosopher interested in science must be largely a student of world 3 objects.