We must be careful, however, not to imagine that what Herakleitos thus discovered was a logical principle. This was the mistake of Lassalle’s book.[373] The identity in and through difference which he proclaimed was purely physical; logic did not yet exist, and as the principle of identity had not been formulated, it would have been impossible to protest against an abstract application of it. The identity which he explains as consisting in difference is simply that of the primary substance in all its manifestations. This identity had been realised already by the Milesians, but they had found a difficulty in the difference. Anaximander had treated the strife of opposites as an “injustice,” and what Herakleitos set himself to show was that, on the contrary, it was the highest justice (fr. 62). Footnote 373: The source of his error was Hegel’s remarkable statement that there was no proposition of Herakleitos that he had not taken up into his own logic (_Gesch. d. Phil._ i. 328). The example which he cites is the statement that Being does not exist any more than not-Being, for which he refers to Arist. _Met._ Α, 4. This, however, is not there ascribed to Herakleitos at all, but to Leukippos or Demokritos, with whom it meant that space was as real as matter (§ 175). Aristotle does, indeed, tell us in the _Metaphysics_ that “some” think Herakleitos says that the same thing can be and not be; but he adds that it does not follow that a man thinks what he says (_Met._ Γ 3. 1005 b 24). I take this to mean that, though Herakleitos did make this assertion in words, he did not mean by it what the same assertion would naturally have meant at a later date. Herakleitos was speaking only of nature; the logical meaning of the words never occurred to him. This is confirmed by Κ, 5. 1062 a 31, where we are told that by being questioned in a certain manner Herakleitos could be made to admit the principle of contradiction; as it was, he did not understand what he said. In other words, he was unconscious of its logical bearing. Aristotle was aware, then, that the theories of Herakleitos were not to be understood in a logical sense. On the other hand, this does not prevent him from saying that according to the view of Herakleitos, everything would be true (_Met._ Δ, 7. 1012 a 24). If we remember his constant attitude to earlier thinkers, this will not lead us to suspect either his good faith or his intelligence. (See Appendix, § 2.) [Sidenote: Fire.]