Alcmaeon maintains that the bond of health is the 'equal balance' of the powers, moist and dry, cold and hot, bitter and sweet, and the rest, while the 'supremacy' of one of them is the cause of disease; for the supremacy of either is destructive. Illness comes aboutdirectly through excess of heat or cold, indirectly through surfeit or deficiency of nourishment; and its centre is either the blood or the marrow or the brain. It sometimes arises in these centres from external causes, moisture of some sort or environment or exhaustion or hardship or similar causes. Health on the other hand is the proportionate admixture of the qualities.

Anaxagoras of Clazomenae, son of Hegesiboulos, held that the first principles of things were the homoeomeries. For it seemed to him quite impossible that anything should come into being from the non-existent or be dissolved into it. Anyhow we take in nourishment which is simple and homogeneous, such as bread or water, and by this are nourished hair, veins, arteries, flesh, sinews, bones and all the other parts of the body. Which being so, we must agree that everything that exists is in the nourishment we take in, and that everything derives its growth from things that exist. There must be in that nourishment some parts that are productive of blood, some of sinews, some of bones, and so on-parts which reason alone can apprehend. For there is no need to refer the fact that bread and water produce all these things to sense-perception; rather, there are in bread and water parts which only reason can apprehend.

Anaximenes ... declared that air is the principle of existing things; for from it all things come-to-be and into it they are again dissolved. As our soul, he says, being air holds us together and controls us, so does wind [or breath] and air enclose the whole world.