Pluralism is the doctrine that reality is composed of many ultimate substances and that no single explanatory system or view of reality can account for all the phenomena of life. Here, I will discuss the ideas of two great Ancient Greek thinkers who were pluralists, Empedocles and Anaxagoras.
Empedocles (490 B.C. - 430 B.C.) theorized that all matter was composed of four basic ingredients: fire, air, water, and earth. He believed that two forces, harmony and discord, interact to bring together and separate the four substances. Believing in the transmigration of souls, he declared that salvation requires abstention from eating the flesh of any animals because their souls may once have inhabited human bodies.
He tried to find the basis of all change. He believed that an existence could not pass into non-existence, and vice versa. He viewed changes as the result of mixture and separation of unalterable substances. Thus, coming into existence from a non-existence, as well as a complete death and annihilation, are impossible; what we call coming into existence and death is only mixture and separation of what was mixed.
Anaxagoras (500 B.C. - 428 B.C.), another great Ancient Greek thinker who was a pluralist, is best remembered for his cosmology and for his discovery of the true cause of eclipses. In doing so, however, he was accused of contravening the established religion and was forced to flee to Lampsacus, an Ancient Greek colony. His cosmology grew out of the efforts of earlier pre-Socratic philosophers to explain the physical universe in terms of a single element. The most original aspect of his system was his doctrine of nous ("mind," or "reason"), according to which the cosmos, including all living things, was created by mind in a process of attraction of "like to like"; mind also accounts for the power of living things to extract nourishment from surrounding substances. He is famous for introducing the cosmological concept of Nous (mind), as an ordering force. He regarded material substance as an infinite multitude of imperishable primary elements, referring all appearance and disappearance to mixture and separation respectively.