The quote "How could hair come from what is not hair or flesh from what is not flesh?" is from the Greek philosopher Anaxagoras. Anaxagoras was a Pre-Socratic philosopher who lived in the 5th century BC and was a contemporary of Socrates. He is known for his work in natural philosophy and for his contributions to the development of scientific thought.

In his philosophy, Anaxagoras argued that everything in the universe is made up of tiny, indivisible particles called "seeds" or "seeds of things." He believed that these seeds could combine to form new things, but he also maintained that the seeds could not be destroyed or created. This led him to make the statement that "How could hair come from what is not hair or flesh from what is not flesh?", as he believed that these things could not arise from nothing.

Anaxagoras's ideas had a significant influence on the development of natural philosophy and science, and his work is considered to be an important precursor to modern scientific thought.