Aristotle's Thoughts on Reality

Plato was a rationalist, viewing our knowledge of reality as derived from intuitive reason, and an idealist, locating ultimate reality in an eternal, immutable world of Ideas. Aristotle was an empiricist, anchoring all knowledge of reality in perceptual experience, and a realist, identifying reality with the concrete spatio-temporal objects of this world. The painter, Raphael portrays this difference masterfully when he painted an older Plato pointing at the heavens and a younger Aristotle pointing at the ground.

Like Plato's, Aristotle's philosophy is anti-Sophist in that it tries to develop a theory of the good life. This theory is based on the foundations of our knowledge of the stable nature of reality.

Aristotle describes metaphysics as, "the theory of being as being and of what 'to be' means." As with any science, metaphysics strives to know its objects through first principles. Referring to substances or "primary beings," their modifications, their processes of coming to be or ceasing to be, or their qualities, for example, the fundamental meaning relates to substances as the primary beings, so that metaphysics will deal with "the first principles and primary factors of primary beings." Aristotle distinguishes between "primary substances" as being humans or horses, and the group that they belong to, like humanity or animality, as "secondary substances." Where as Plato believed that humans and humanity are both "primary substances." Aristotle also believed that two different humans are separate "primary substances", for example Socrates and Plato are both "primary substances", even though they share the same genus and species. Substance, also, have no opposites, yet only substances can have opposite qualities. Like, a tree has no opposite, however a tree limb can be strong, and turn into weak, and those are opposites. Aristotle tells us that primary substances are combinations of form and matter.

Aristotle rejects Plato's two-tired philosophy on reality, maintaining that all that is real is part of one world, not two different, but connected ones.