Most of the following exchange between myself and Tom Napier, editor of the PhACT newsletter at the time, was published in 1995. The first four segments--two by me and two by Tom--are Copyright © 1995, PhACT, and reprinted with permission. The final piece is Copyright © 2003, William A. Wisdom.

SOLIPSISM: WHAT CAN WE SAY ABOUT IT?
William A. Wisdom

I would not, in the normal course of events, have thought to address this topic. But for a couple of reasons, I'm glad that the Editor invited me to do so. Solipsism is sometimes taken to be either the most consistent and radical form, or the reductio ad absurdum, of skepticism. So as skeptics we have to be interested in it. And, further, it gives me a chance to illustrate a principle presented in my "SKEPTICISM AND THE JUSTIFICATION OF BELIEF".

In A Dictionary of Philosophy (2nd ed. rev., St. Martin's Press, 1984), CSICOP Fellow Antony Flew calls solipsism "the theory that I am the sole existent. To be a solipsist I must hold that I alone exist independently, and that what I ordinarily call the outside world [including my body] exists only as an object or content of my consciousness. This doctrine, though doubtless psychologically very difficult, if not impossible, to hold, is philosophically interesting in that many thinkers have thought it necessary to attempt refutations, or even to admit that, however bizarre, it is strictly irrefutable. Once we concede...that the immediate objects of sense experience are mind dependent (ideas, impressions, sense data, etc.), it is indeed questionable whether we can argue validly to the existence or nature of a mind independent external world."

I have no interest in surveying the enormous number and variety of arguments for and against solipsism. In the passage just quoted, Flew briefly summarizes the line of thought, one or another version of which is usually offered to support solipsism or at least to show that it cannot be disproved. Arguments meant to undermine solipsism by suggesting that the solipsist is inconsistent in addressing "other people" are, of course, foolish--there's nothing inconsistent or even unusual about talking to yourself.

But there is something thoroughly wrong-headed with both the adoption and the rejection of solipsism--i.e., something wrong-headed about getting involved in the issue at all. First, note that solipsism purports to be a statement about matters of extra-linguistic fact. If true, it is supposed to be true by virtue of what sorts of things do and don't actually exist, not by virtue of what words mean. Solipsism, if true, is not a truth of logic, a tautology; it is a truth about reality.

Now imagine that you're not a solipsist, and that there's a solipsist before you. Ask her: "How would things be observably different if your solipsism were false, and there did actually exist physical objects impinging on the sense-organs of a body so intimately associated with your states of mind as to be your body?" Since solipsism is not a logical truth but a statement of fact, what you describe has to be possible. I propose that (a) there is no observable difference between the solipsist's world and the world of the anti-solipsist; that therefore (b) there is no way to settle the (merely apparent) disagreement between them; and that therefore (c) they are both making vacuous claims with no factual content: despite appearances, their respective claims are not about matters of fact--indeed, they're not about anything, and one wastes one's time running the empty sounds though one's mind.

I know that a common reaction to this line of thought is: "Fine...but you haven't settled the issue." Please understand: my entire point is that there is no issue to settle!

EDITOR'S NOTE
[Tom Napier]

I was curious to see how a philosopher would deal with the skeptic's core dilemma: given only sense impressions, how can one be sure of anything. I was not expecting to have the problem defined out of existence. I suspect that if Bill's hypothetical solipsist were the solipsist (rather than merely a believer in solipsism) she could easily prove it by defining the questioner out of existence. Regrettably, solipsism is still alive and well, not only in the fuzzy-thinker's dictum, "everyone creates their own reality" but also, more seriously, in the Strong Anthropic Principle and in some popular interpretations of Quantum Theory.

REPLY TO THE EDITOR
[William A. Wisdom]

I was disappointed that the Editor decided--as certainly was his prerogative--to pan my remarks on solipsism in the last issue of Phactum. He had invited me to write the article. So it seems rather petty that he should then object in print that I hadn't written the article that he'd expected. If he wanted a certain doctrine to be promulgated, then he should have done it himself.

I have two responses to his comments. First, I don't see how what I did can reasonably be called "defining the problem out of existence". To be sure, I argued that there is no problem here. But I don't see that any part of that argument depends on defining or redefining terms. Or if it does, the background rationale was explicitly said to lie in another article of mine, to which I directed the reader's attention.

And second, the Editor's solipsist could not possibly defend her position "by defining the questioner out of existence" if, as I explicitly--and, I should think, reasonably--claimed, her solipsism if true is true by virtue of extra-linguistic rather than linguistic facts. Things like squircles can be defined out of existence when, but only when, the meanings of terms prohibit their existence. ("Squircle" means "square circle". I just defined squircles out of existence.) Unicorns, and existents other than myself, cannot be defined out of existence.

EDITOR'S SECOND NOTE
[Tom Napier]

For the benefit of readers who have no idea what all this is about, I should explain that Bill and I have been thrashing out the question of solipsism for some months and have finally honed in on where we differ. We agree that no other person's claim to believe in solipsism need be taken seriously since, if it were true, we, being mere figments of someone else's imagination, could not be self-aware. (So much for Lewis Carroll's Red King.) Thus we need only consider our own belief that we are the only person who exists.

Bill supposes that the mental life of the solipsist could not be distinguished from the mental life of the non-solipsist and that therefore the point is moot. I assume that, if the external world is a figment of my imagination, "imagination" is being used in its everyday sense. That is, what I imagine is, to some degree, under my control. Being a solipsist would thus be like being an author living in one's own book. This interpretation of solipsism is, of course falsifiable. For some time now I have been imagining Bill being abducted by aliens but to no avail: he's still here.

My original intention, in broaching the subject, had been to address two topics of interest to the skeptic. One was the long-running philosophical issue of whether we can believe anything, given that we only have sense impressions as input....The other was the more practical issue of whether any belief based on a direct mental influence on [sic] the external world has validity. Many paranormal and fringe-science beliefs fall into this category.

FINAL REMARKS (2003)
William A. Wisdom

By the time the exchange gets to the second editorial note, Tom seems to think that he understands what solipsism is, and where our disagreements lie. He clearly does not. Tom thinks that solipsism includes the belief that "the external world is a figment of my imagination." Reread Flew's definition of and remarks on solipsism. No minimally sensible solipsist has ever thought that what we call the outside world is a figment of her imagination, or that she could make material objects disappear by an act of her will. Such a view would be silly in the extreme. And while a solipsist is mistaken in asserting solipsism (for the reason given initially), she is not stupid. (She knows perfectly well, for example, that there are solid objects like trees and mountains whose nature and existence will not yield to her desires.)

I'll mention one more disagreement in closing. Tom refers to "the long running philosophical issue of whether we can believe anything, given that we only have sense impressions as input." Not only is this not a long-running philosophical issue. It is not and never has been a philosophical issue at all. How could it be?! Lots of professional and lay philosophers think that "we only have sense impressions as input". But not one of them has ever doubted that we can and do believe lots and lots of things.

I make one final remark on a confusion in Tom's first editorial note. There he uses the clause: "if Bill's hypothetical solipsist were the solipsist (rather than merely a believer in solipsism)". This betrays a further ignorance of what it means to be a solipsist (reread Flew). To be a solipsist is to be a believer in solipsism. He here suggests that to be a solipsist is to be the only existing thing. But that's not what solipsism means. Tom's tacit distinction between a solipsist and one who believes in solipsism is nonsense.