How much do you really know about what goes on in anyone else’s mind? Clearly you observe only the bodies of other creatures, including people. You watch what they do, listen to what they say and to the other sounds they make, and see how they respond to their environment — what things attract them and what things repel them, what they eat, and so forth. You can also cut open other creatures and look at their physical insides, and perhaps compare their anatomy with yours.
But none of this will give you direct access to their experiences, thoughts, and feelings. The only experiences you can actually have are your own: if you believe anything about the mental lives of others, it is on the basis of observing their physical construction and behavior.
To take a simple example, how do you know, when you and a friend are eating chocolate ice cream, whether it tastes the same to him as it does to you? You can try a taste of his ice cream, but if it tastes the same as yours, that only means it tastes the same to you: you haven’t experienced the way it tastes to him. There seems to be no way to compare the two flavor experiences directly.
Well, you might say that since you’re both human beings, and you can both distinguish among flavors of ice cream — for example you can both tell the difference betweeen chocolate and vanilla with your eyes closed — it’s likely that your flavor experiences are similar. But how do you know that? The only connection you’ve ever observed between a type of ice cream and a flavor is in your own case; so what reason do you have to think that similar correlations hold for other human beings? Why isn’t it just as consistent with all the evidence that chocolate tastes to him the way vanilla tastes to you, and vice versa?
What I like most about Nagel’s approach is that you don’t have to know anything at all about philosophy to understand and appreciate the puzzling nature of the problems he presents. His conversational tone makes it easy for curious teenagers (and adults) to jump right into trying out ideas and thinking about arguments for and against them. The book balances in a masterful way a presentation of the complexity of the problems with an explanation of them that welcomes newcomers to philosophy to begin wondering about them.
What Does It All Mean?
I love Thomas Nagel’s short 1987 book What Does It All Mean? It’s a really accessible introduction to philosophy for high school students and up, and it captures much of what drew me to philosophy in the first place.
The book focuses on some of the philosophical problems that, as Nagel notes, “reflective human minds find naturally puzzling.” Nagel discusses nine philosophical issues, including whether we can know anything, the mind-body problem, free will, the nature of justice, ethics, and the nature of death.
Here is an excerpt, from the chapter on other minds: