In existographies, Hippocrates (c.460-370BC) (IQ:175|#213) (Cattell 1000:165) [RGM:27|1,500+] (Murray 4000:2|Med) (FA:17) (CR:43) was a Greek physician, commonly known as the “father of medicine”, noted for his ideas on animal heat, affinity theory, and a non-supernatural basis of disease.
Hippocrates promoted an animal heat view of human animation in relation to fire; reasoning that “heat, a quantity which functions to animate, derives from an internal fire located in the left ventricle”.  This was referred to as the doctrine of internal heat. 
Hippocrates, in the context of the history of affinity theory, in circa 410BC, promoted the theory that “like assorts with like”; sometimes called Plato's first law of affinity. 
Quotes | Atheism
See main: Hippocratic reductionismThe following are noted atheism-themed quotes:
“Men think epilepsy divine, merely because they do not understand it. We will one day understand what causes it, and then cease to call it divine. And so it is with everything in the universe.”
— Hippocrates (c.400BC), popular atheism quote
Quotes | On
The following are related quotes:
“Hippocrates in time arrived at the conclusion that he had not sought whether the heart or the head was the seat of either reason or sense in man and beast.”
— Jean de La Fontaine (c.1690), 29th fable quote; inscribed at the base of the 1869 statue of Democritus mediating on the seat of the soul, Paris
Quotes | By
The following are noted quotes:
“Is there supernatural in disease?”
— Hippocrates (400BC), On the Sacred Disease; ruminated on by Jean Fernel, 1548; cited by Charles Sherrington, 1938 
1. Schneider, Eric D. and Sagan, Dorion. (2005). Into the Cool - Energy Flow, Thermodynamics, and Life, (pg. 35). Chicago: The University of Chicago Press.
2. Mendelsohn, Everett I. (1964). Heat and Life: the Development of the Theory of Animal Heat (pg. 9). Harvard University Press.
3. (a) Sherrington, Charles. (1938). Man on His Nature (pg. 5). Cambridge University Press, 1950.
(b) On the Sacred Disease – Wikipedia.
4. Jammer, Max. (1957). Concepts of Force: a Study of the Foundations of Dynamics. Dover.
● Hippocrates – Wikipedia.