In existographies, Hippo (c.500-440BC) (FA:6), aka Hippon, “Hippo of Rhegium” (Drachmann, 1922), or “Hippo of Samos” (Whitmarsh, 2015), was a Greek natural philosopher, characterized as being “heir to the traditions of Thales, Anaximander, and Anaximenes”, noted for []

Philosophy
Hippo held water and fire to be the primary elements, with fire originating from water, and then developing itself by generating the universe. He thought that there is an appropriate level of moisture in all living things, and disease is caused when the moisture is out of balance. He believed the soul as arising from both mind and water.

In his On the Soul, Aristotle says the following: [3]

“Of more superficial writers, some, e.g. Hippo, have pronounced the soul to be water; they seem to have argued from the fact that the seed of all animals is fluid, for Hippo tries to refute those who say that the soul is blood, on the ground that the seed, which is the primordial soul, is not blood.”

Aristotle, supposedly, characterized him as being an excessive materialist. [4]

Atheism
Hippo was known, to some, among the Greeks, as an atheist. [2]

Quotes | On
The following are quotes on Hippo:

“In the list given by Drachmann [1922], others designated atheoi in the period up to the 3rd century BC are Diogenes of Apollonia, Hippo of Rhegium, Diagoras of Melos, Prodicus of Keos, the aristocrat Critias of Athens, Theodorus of Cyrene, Bion of Borysthenes, and Euhemerus of Messina.”
— Michael Palmer (2013), Atheism for Beginners [3]

See also
● Augustine (of Hippo)

References
1. (a) Palmer, Michael. (2013). Atheism for Beginners: a Coursebook for Schools and Colleges (pg. 15). Lutterworth Press.
(b) Drachmann, Anders B. (1922). Atheism in Pagan Antiquity (pg. 13). Gyldendal.

2. Whitmarsh, Tim. (2015). Battling the Gods: Atheism in the Ancient World (pg. 63-64). Vintage Books.
3. Aristotle. (322BC). The Complete Works of Aristotle, Volume One (editor: Jonathan Barnes) (pg. 646). Princeton University Press, 1995.
4. Polansky, Ronald. (2007). Aristotle’s De Anima: a Critical Commentary (Hippo, pg. 80). Cambridge University Press.

Further reading
● Shapiro, S. (1999). “Hippon the Atheist: the Surprising Intelligent Views of Hippon of Samos”, Journal of Ancient Civilizations, 14:111-23.
● O’Grady, Patricia F. (2017). Thales of Miletus: the Beginnings of Western Science and Philosophy (§: Hippo, pgs. 23-24). Taylor & Francis.

External links
● Hippo (philosopher) – Wikipedia.