The ancient Greek philosophy was divided into three great branches; physics, or natural philosophy; ethics, or moral philosophy; and logic. This general division seems perfectly agreeable to the nature of things.
The great phenomena of nature, the revolutions of the heavenly bodies, eclipses, comets; thunder and lightning, and other extraordinary meteors; the generation, the life, growth, and dissolution of plants and animals; are objects which, as they necessarily excite the wonder, so they naturally call forth the curiosity of mankind to inquire into their causes. Superstition first attempted to satisfy this curiosity, by referring all those wonderful appearances to the immediate agency of the gods. Philosophy afterwards endeavoured to account for them from more familiar causes, or from such as mankind were better acquainted with, than the agency of the gods. As those great phenomena are the first objects of human curiosity, so the science which pretends to explain them must naturally have been the first branch of philosophy that was cultivated. The first philosophers, accordingly, of whom history has preserved any account, appear to have been natural philosophers.
In every age and country of the world, men must have attended to the characters, designs, and actions of one another; and many reputable rules and maxims for the conduct of human life must have been laid down and approved of by common consent. As soon as writing came into fashion, wise men, or those who fancied themselves such, would naturally endeavour to increase the number of those established and respected maxims, and to express their own sense of what was either proper or improper conduct, sometimes in the more artificial form of apologues, like what are called the fables of Aesop; and sometimes in the