Alberto moves on to discuss David Hume (1711-1766), another important empiricist. Hume wrote a great deal about human nature. Sophie finds this tiresome—she points out that all the philosophers she’s been reading about are men—perhaps as a result, their books seem to say almost nothing about childhood, femininity, pregnancy, etc. Alberto admits that Sophie has a point, but he also stresses that Hume focused on the experiences of young children, something that sets him apart from many of his philosopher peers.
Once again the theme of women and sexism in philosophy comes up, as Sophie gets frustrated with the rather obvious fact that all the philosophers she’s learning about are men (with the exception of Hildegard, who isn’t nearly as famous as the others). This again brings up the idea that being a professional philosopher requires a certain level of privilege—rights, education, safety, and money.
Alberto explains that Hume acted as a kind of “janitor” cleaning up the philosophy of the Middle Ages. For example, Hume suggested that man’s belief in angels was a delusion—a “complex idea” made up of two simpler, unrelated concepts (the concept of a human being and the concept of wings or flight). In general, Hume was interested in classifying different kinds of ideas and perceptions and throwing out ideas that weren’t grounded in real, empirical experience. He argued that complex ideas aren’t real: complex ideas simply signal the mind playing tricks on itself.
Hume could be said to fall into the same tradition as Augustine and Aquinas: a great thinker whose main contribution was reworking other people’s ideas. With his emphasis on observation and empiricism, Hume reflects the dominant scientific ethos of the era, which we’ve already seen in Sir Isaac Newton. Instead of relying on abstract metaphysical ideas, Hume trusts only what he can measure and control.
Alberto explains Hume’s notion of ego to Sophie. The ego is the self, the “I,” with which we experience the world. Hume’s analysis of ego is similar to that of Descartes, who began by assuming the existence of an “I” and nothing else. But where Descartes takes it for granted that the ego is always the same—an unchanging eye that observes the world—Hume suggested the opposite. The ego is always changing, just as our personalities and thoughts are always changing. In short, “I” am not the same person “I” was five minutes ago. Alberto points out that Hume’s analysis is surprisingly similar to that of Buddha, 2,500 years before.
Hume’s arguments more or less refute Descartes’s most famous idea, “I think, therefore I am.” Hume’s point is that even this theoretical “I” is altogether unlike the “self” with which Descartes conflated it. At any given moment there may be an “I” that thinks; and yet it’s impossible to prove that this is the same “I”—the same being—that persists over time. Alberto draws interesting parallels between Hume and Buddha, suggesting that Western philosophy isn’t as original or self-contained as some have claimed.
Another important element of Hume’s thought was his theory of causation. Hume argued that people are so used to seeing the same things happen again and again that they begin to think in rigid, unchanging terms—we expect a penny to fall to the ground if we release it from our hand. Young children haven’t yet been trained to think in such rigid terms, so they’re more open-minded in their experiences.
Hume radically reworks Aristotle, arguing that causation, quite aside from being a “real” thing, is impossible to measure, and therefore nonexistent. (Hume’s arguments would later appear in the writings of John Dewey and William James.)
One further consequence of Hume’s theory of causation is that causation, as we usually understand it, is just an illusion. We don’t really know why a penny falls to the ground—we’re just so used to seeing it happen that our mind tricks us into thinking up a cause for it. Alberto gives another analogy: people think that lightning is the “cause” of thunder because thunder comes after lightning. But this is just an illusion: lightning and thunder are just two sides of the same coin: they’re part of the same phenomenon. In this way, all humans have been trained to believe in the illusion of causation.
It may seem impossible that something as intuitive as causation could be an illusion, and yet Hume is persuasive in the way that he refutes these intuitive assumptions. It’s a mark of Hume’s empiricism that he’s willing to dismiss causation because it can’t be measured—this reminds us that Hume trusted his observations, not his mind’s assumptions. (It’s worth mentioning that Alberto’s example of lightning and thunder is taken from The Genealogy of Morals by Nietzsche—not Hume.)
Hume also had a complex theory of morality. Hume argued that morality had no relation to reason whatsoever. We believe that it’s wrong to kill someone, not because of any logical reason, but because we’re sympathetic to the victim. The importance of this is that we shouldn’t make the mistake of thinking that we can use reason to solve all our problems—we need to deepen our feelings for other people as well. Alberto clarifies this with an example: the Nazis killed millions of people, but it wasn’t an error of rationality that made them do so—on the contrary, plenty of Nazis were calm, cool-headed people.
Hume might seem cold and clinical in his thinking—consider how ready he was to dismiss causation altogether, just because it couldn’t be scientifically measured. And yet there’s also a compassionate, moral side to Hume’s thinking. In many ways, Hume hasmorefaith in compassion than most—he sees evil as a totally moral and emotional concept, rather than a deviation in reason (as Socrates argued, centuries before).