Jim asked:

I am a 16 year old and I have been asking myself the same question for a very long time but only recently was able to finally word the question. Isn’t it true that there can not be a certainty of anything outside a person’s current observed world?

It still sounds very weird but if I am sitting in a room in a building that I walked into myself, I saw all of my surrounding as I entered the building and the room. The door is closed and there is no way for me to observe anything on the outside of the room. I can say that I know exactly what is outside that door because I saw it as I came in the room, but in reality I have zero way of being completely certain of anything I can’t see or hear outside the room. I could, potentially, be in a room floating in space and have no way of knowing, given there isn’t any obvservable evidence of my location.

It may sound strange, but I believe it could be related to particle physics, etc. The fact is that I have no certainty of anything outside my personal observed ‘picture’: the surroundings in my field of vision and what I can hear around me.

Answer by Helier Robinson

You are quite right. The only certainty is what I perceive now. We all have perception substitutes: namely, memory, expectation, and belief, but all are fallible. This is the conclusion that Descartes came to with his cogito ergo sum, which translates literally to ‘I think therefore I am’. What Descartes meant was that he was conscious and therefore he existed; because all the contents of consciousness have to exist in order to be within consciousness, and he was conscious of himself, as perceiving subject. And it is possible that all that you are conscious of now is the totality of existence: all your memories, expectations, and beliefs (that is, all those that you are conscious of now) are false.

This is known as solipsism, from sole ipse, meaning alone I am. Many philosophers in the past have tried to prove that solipsism is false, without success, in my opinion. In principle, there are two ways to prove it false: one is to show that it is self-contradictory, and the other is to prove that something exists outside of your consciousness, now.


Answer by Geoffrey Klempner

My take on this would be that the best that one can achieve in attacking solipsism is to reduce the solipsist to silence. Many would take that as a conclusive refutation, but I wouldn’t go quite that far.

The solipsist still believes something. We need to show that what the solipsist believes can’t be possible if solipsism is assumed. What the solpist believes is that there is such a thing as truth. Otherwise it would make no sense to say, ‘Solipsism is true’, or ‘Every theory is false except for solipsism’.

Wittgenstein, in his argument against a ‘private language’ (in the Philosophical Investigations) showed that the notion of truth, as something that minimally involves the notions of ‘right’ and ‘wrong’ only makes sense against a backdrop of intersubjectivity – individual subjects in a world communicating with one another in a ‘public language’.

If solipsism is assumed, there can be no other subjects. No-one exists apart from myself. It follows from Wittgenstein’s argument against a private language that one cannot meaningfully assert (even to oneself) that ‘solipsism is true’ or ‘I believe in solipsism’. All you can do, to indicate the thing you ‘see’ (or seem to see), is to gesture wordlessly, or endlessly repeat the words, ‘I mean THIS!’