Knowledge about our own mental states seems to be the most secure thing in the world, doesn’t it? I certainly know what I feel and think right now and I know it more securely than any other thing I might know. Right? Philosopher Eric Schwitzgebel begs to differ.

Skepticism about our knowledge of the external world (questioning whether we know anything about the external world) has a long tradition in philosophy. You believe that you know that you have two hands, don’t you? But you could be dreaming that you have two hands or it could be that an evil demon (of the kind considered by Descartes in the Metaphysical Meditations) is fooling you. Do you really know that you are not dreaming? Do you really know that you are not being fooled by an evil demon? Or to put it in more contemporary terms, do you really know that you are not in the matrix? And if you do not know these things, then how can you claim to know that you have two hands?

By contrast, knowledge about ourselves seems much more secure! I certainly know that I have the impression to see two hands (whether or not I am in fact seeing two hands). I certainly know that I have the impression to see my laptop (whether or not I am in fact seeing my laptop). Sure, I can be wrong about my past mental states (my memory could fail me), but I could not be wrong about my current mental states.

Schwitzgebel strongly disagrees with this line of thought. He claims that our knowledge of our own subjective experience is at best spotty and that our claims about what we are experiencing are typically unreliable. In any case, they are typically less reliable than claims about the external world! You don’t really know what you are really feeling and thinking right now!

By contrast, psychologist Russ Hurlburt believes that we can gain some accurate knowledge of ourselves, when introspection is done methodically by means of an experimental protocol he designed (Descriptive Experience Sampling). Hurlburt gives subjects a beeper that beeps randomly. When the beeper beeps, subjects are supposed to write down their current experiences. Later on, the psychologist (viz. Hurlburt) interviews these subjects and invites them to describe their past experiences in greater detail.

Recently, Schwitzgebel and Hurlburt teamed up to put Schwitzgebel’s skepticism to test. They interviewed together a subject (named “Melanie”) according to Hurlburt’s experimental protocol. Describing Inner Experience describes the results of this collaboration. Much of the book reports the interviews of Melanie done by Hurlburt and Schwitzgebel.

In the book, Schwitzgebel is constantly skeptical of the claims Melanie makes about her own experiences. In my opinion, the exchanges between Melanie, Schwitzgebel, and Hurlburt somewhat support Schwitzgebel’s skepticism. Like Schwitzgebel, I feel that Melanie is unintentionally led by Hurlburt to describe her past experiences in specific ways. But the reader of this blog ought to make up his or her own mind. This is a fascinating book and I highly recommend it.

Experiments in Philosophy

The impact of psychological research on life's big questions.
Edouard Machery

Edouard Machery is a philosopher of psychology and an experimental philosopher in the Department of History and Philosophy of Science at the University of Pittsburgh.

Tamler Sommers

Tamler Sommers is a professor of philosophy at the University of Houston.

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