Aristotle is a towering figure of ancient Greek philosophy, and his influence has been so prominent and so lasting that during some periods of Western history, he is referred to not by name but simply by the title "The Philosopher." Although he was Plato's student, he matches and perhaps even outshines his predecessor, and it is difficult to think of an area of philosophical thinking that he has not substantially helped to shape. Literary critics often rely on his Poetics when they evaluate the effectiveness of dramatic forms, and moral philosophers still take seriously his considerations of justice and virtue provided in the Nicomachean Ethics. In his many other works, Aristotle also makes fundamental contributions to the study of formal logic, various branches of scientific investigation and even preliminary elements of economic theory.

Plato's influence on Aristotle is evident from their shared concerns and terminology, but Aristotle diverges from the thinking of his predecessor in important ways. Founding his own school of thought – the Lyceum, also called the Peripatos – after leaving Plato's Academy, Aristotle turns away from much of the abstractness of Platonism, perhaps best seen in his criticism of Platonic forms. In the Nicomachean Ethics, for example, Aristotle alludes to Plato's concept of the Form of the Good (which students of Contemporary Civilization study in the Republic), but he ultimately finds it irrelevant for his study of ethics since it is not "practicable or attainable by man." Criticisms such as this one support a broad picture of Aristotle as a proto-empiricist or even "practical" philosopher, a view exemplified in Raphael's famous fresco of The School of Athens, where visitors to the Vatican Museum find Plato pointing upward to the heavens and Aristotle pressing his open palm toward the earth, keeping his feet on the ground, so to speak.

Despite the extraordinary breadth of topics covered in Aristotle's writings, he has left to posterity what many call mere lecture notes or perhaps notes taken by his students in the Lyceum. We know from accounts in antiquity that Aristotle produced many "exoteric" works meant for a more public readership, unlike the surviving "esoteric" texts possibly intended only for use within Aristotle's school. These note-like texts stand in contrast with the artfully written dialogues of Plato. Their dense, sometimes even inscrutable writing style, however, has not dampened the eagerness of his later admirers, and his texts have proven popular well beyond the geographic boundaries of Greece and the chronological boundaries of classical antiquity. Aristotle is widely praised by medieval Islamic philosophers, and he exerts an enormous influence on medieval Christian thinkers such as Thomas Aquinas – two facts borne out in the readings that follow Aristotle in Contemporary Civilization's fall semester.

The largely inescapable legacy of Aristotle's thinking in Western history does not, of course, mean that his works have uniformly enjoyed long-standing approval. Physicists today no longer subscribe to his belief in the four elements of earth, water, air and fire. Nor do biologists think that our rational capacities are based in the heart. Sometimes Aristotle's errors have had more tragic consequences: his political writings – notably his concept of natural slavery – were used to justify the conquest and subjugation of indigenous communities throughout the Americas and elsewhere around the world. Especially in this political dimension, one sees that Aristotle's influence – itself undeniable as a matter of historical fact – serves as a lesson in the pitfalls and abuses of appeals to authority, where the powerful name of "The Philosopher" could persuade theologians and philosophers to murder and enslave.

It would be inaccurate to say, however, that modern readers of Aristotle have been interested only in highlighting his scientific misunderstandings and moral shortcomings. In recent decades, some elements of Aristotle's ethical writings in particular have attracted serious reconsideration if not outright rehabilitation by contemporary philosophers, including Elizabeth Anscombe, Alasdair MacIntyre and Martha Nussbaum. Often called "virtue ethics," this approach to moral philosophy relies in large part on Aristotle's notions of human excellence as explored in his ethical and political writings, and it sits alongside consequence-based and duty-based theories as one of the three dominant approaches to the modern study of ethical human behavior.

Written by Charles McNarama, Core Lecturer, Classics, Columbia University