Anaxagoras's Influence on Plato and Aristotle

By Eduard Lebiedzki, after a design by Carl Rahl - http://nibiryukov.narod.ru/nb_pinacoteca/nbe_pinacoteca_artists_l.htm

While Anaxagoras’s theory on the nature of things ultimately led to disappointment for Plato and Aristotle, it played a role in the formulation of Platonic Ideas and Aristotle’s four causes.

Anaxagoras’s theory comprises two principles: matter and motion. In Aristotle’s account of the former, Anaxagoras posited infinite number of principles where “all things are made of parts like themselves” formed through “aggregation and segregation” and “remain eternally” (MetaphysicsA chp.3). According to Aristotle, the first philosophers thought matter was the only principle, though Anaxagoras made an important advance with his pluralism and an even more considerable one with his principle of motion to explain change.

On the latter, according to Socrates in Plato’s Phaedo, Anaxagoras believes mind “arranges and causes all things” (Phaedo 97b-c). For Socrates, it follows that the mind will do such ordering in the best way. Now that the cause of everything has been found, Socrates expected Anaxagoras to continue to explain “what is best for each and what is good for all in common” (98b), but he was disappointed that Anaxagoras did not develop his concept to explain causes of things but instead pointed at other causes such as material ones. Likewise, Aristotle accuses Anaxagoras of using reason as a “deux ex machina” (MetaphysicsA chp.4), only raising it when he is unable to explain based on other events

Nonetheless, Anaxagoras’s theory serves as a precursor for Plato and Aristotle. His principle of motion led Plato to his theory of Ideas since it caused Socrates to consider “the good which embraces and hold together all things.” From there, he will arrive at how “anything comes into existence […] by participating in the proper essence of each thing” (Phaedo 101c).

For Aristotle, he relates Anaxagoras’s theory as a historical backdrop to substantiate his four causes. While he rejects Anaxagoras’s account of matter since it “doubles the world […] by positing a principle for each and every quality” (CP sec3.2 35), the same reason why he rejects Platonic Ideas, he cites Anaxagoras for advancing beyond the material cause to the efficient cause even as he chides him for using it as a deux ex machina.

Plato and Aristotle present similar accounts of Anaxagoras’s theory, but it led them to different outcomes. Plato’s approach is from the universal to the particular while Aristotle’s is from the particular to the universal (CP sec3IA). This affects their reasoning – for Plato, if the mind is the cause, it must order things for the best and how it knows the best is from a participation in the Ideas, while for Aristotle, he examines the history of philosophy only to try to find other causes or strengthen his concept of four causes (MetaphysicsA chp.3). Both are seeking a more fundamental cause, which Plato finds in Ideas and his Idea of the good which all Ideas participate (CP sec2IIC5 26) and Aristotle finds in teleology which grounds his formal and final cause.

References:

Aristotle. Metaphysics A. The Internet Classics Archive, http://classics.mit.edu//Aristotle/metaphysics.html

Plato. Phaedo. William Heinemann, 1913.

Van Riel, Gerd, Layne, Danielle A. Course Packet.