According to Durant, philosophy begins with an investigation into the nature of things, both in terms of human nature and their interaction with the world around them. The Story of Philosophy traces how various Western philosophers grappled with these issues in different ways over the centuries.

Plato and Aristotle set in motion thousands of years’ worth of debate when Plato located the essence of reality in abstract forms, of which material objects were only a representation. Reality had to be universal, and no physical object could be universal because it was bound by its physical dimensions: Just as it had been created, it was bound to decay. Aristotle, by contrast, argues that while objects may all have a specific existence, they are more real than universal archetypes, which have no existence outside the imagination. A logical process like a syllogism can establish generalities based on the combination of particulars (e.g., men are rational, Socrates is a man, therefore Socrates is rational [70-71]).

The moderns assume the basic framework of this debate, while reframing it as a contest between science and idealism. Bacon, Spinoza, and Russell were empiricists who each had great confidence in the ability of human beings to gain knowledge through sensory perception and scientific inquiry, even if they disagreed about the precise possibilities and limits of such inquiry.