The Greeks used mythology to explain how the world was formed and how it operated, before Milesian philosophy was created (Downey 1). Anaximander like other Milesians thought that the world was created and operated by natural forces (Downey 1). Experts believed that Anaximander wrote a book on nature, geography and many other topics, but hardly any of his writings have survived over time. A question that Anaximander tried to answer in his book was "what is the real nature of matter" (Downey 1). What he came up with to answer this question was what he called "apeiron," meaning an endless, indeterminate matter (S. Morris 20). He said this matter never got old and yielded materials from which everything on the earth is made up of (Downey 3). He also explained the beginning of life and biology in his book. Anaximander thought that life was created in water and then moved to the earth, which was very close to the theory in modern science (Downey 2). He had a theory about the evolution of human that was also close to modern science (Downey 2). He believed that humans evolved from animals because if humans started out as infants they would have died without someone to take care of them (Downey 2).