Aristotle’s writings show that he was well versed in Platonic philosophy, including the centerpiece of Plato’s philosophy, the Theory of Forms. According to this theory, the objects of experience are just shadows of a higher world of Forms that lie beyond sensory experience. For example, the various things we see in this world that we call beautiful have beauty because they participate in the Form of Beauty, which is itself immaterial and eternal. In Plato’s view, the purpose of philosophy is to train the intellect to see beyond appearances and to grasp the higher world of Forms.

Aristotle’s background as the son of a doctor served as an important counterbalance to the idealism of Plato’s philosophy. Aristotle was probably brought up to pursue a medical career, and his writings on biology show a very keen understanding of anatomy. Throughout his writings, Aristotle refers to biology as a paradigm for making sense of the world, much as Plato refers to mathematics. This emphasis on biology leads Aristotle to favor close observation of natural phenomena and careful classification as the keys to making sense of things. As a result, Aristotle’s philosophy is much more empirically oriented than Plato’s. Crucially, Aristotle rejects the idea that we can only make sense of this world by appealing to invisible entities beyond it.

Aristotle’s influence on subsequent generations is immense. Only Plato can compare in importance. Though Aristotle’s works were lost to the West for many centuries, they were preserved by Arab scholars and transmitted back to Europe in the Middle Ages. Thanks mostly to the work of St. Thomas Aquinas, Aristotle’s writings carried an authority in the late Middle Ages that was second only to the Bible. Many of Aristotle’s ideas were disproven starting with the Enlightenment, although his work in logic and biology was not significantly improved upon until the nineteenth century. In some ways, modern science and philosophy found their legs by rejecting or disproving many of Aristotle’s results but, his methods continue to have a deep influence on philosophical and scientific thought.