Anaximander was the second philosopher of the Milasian School and was a pupil of Thales. His dates are uncertain, but he was said to have been 64 years old in 546 B.C. According to Apollodorus, he was born in the second or third year of the forty-second Olympiad (611-610 B.C.). Of his life little is known; Zeller infers from the statement of Aelian to the effect that he led the Milesian colony into Apollonia that he was a man of influence in Miletus. Like other sixth-century thinkers, he was a primitive scientist and philosopher. Anaximander held that the unlimited is the beginning of all things, that is, all things are derived from the infinite substances and becomes infinite again when their period of existence is complete. There is no beginning of the infinite, for in that case it would have an end. He agrees with Thales that there is only one primal substance, but it is neither water nor any other kind that we know. According to Anaximander, the primal substance is something without limit in space and time and it encompasses all the worlds – including ours. He maintained that the primal substance is transformed into various substance and these substances transformed into each other. For instance, where there has been fire, there are ashes, which are earth. Anaximander had an argument to prove that the primal substance could not be water, or any other known element. If any one of these substances were primal, it would conquer the others. In fact, this was the idea of justice – of not overstepping bounds – in Anaximander philosophy and one of the most profound of Greek beliefs. For Greeks, even the gods were subject to justice like humans. Note that along the same lines the conception of cosmic justice dominates the metaphysics of Heraclitus metaphysics, which prevents the strife in the complete victory of either. It is very important to understand that the concept “justice” as Greeks used hardly corresponds to what a today we call justice.

 The best hypothesis the Anaximander came up with was the earth floats freely, and is not supported on anything. (Aristotle objected to this theory, he often rejected the best hypothesis of his time.) We can say that Anaximander was the first to conceive the idea of evolution. According to him, at first earth was in the liquid state. The present state of the earth is the result of graduated drying up process. He also believed that all living things are originate in slime, and that humankind had evolved from a species of less complex organism. Anaximander is scientific and rationalistic, whenever he hypothesis, and certainly interesting of the Milesian triad.