One attempt to argue against solipsism is by appealing to phenomenal conservativism. A brief summary of this argument is given below:

If something like phenomenal conservatism is true, then since it strongly seems to us as if there are other minds, we have good reason to believe that there are other minds.

This truly is an awful argument, for reasons I will now discuss. For one, this argument completely misses the point of “the problem of other minds”. The whole reason why this epistemological problem even exists in the first place is precisely because the existence of other minds are not apparent. Contrary to what is asserted in the argument, it does not strongly seem as there are other minds.

While it may strongly seem as if people have arms, legs, hands, heads, and other body parts, it does not seem as if those people have perceptions since these perceptions are unobservable from a third-person perspective (unlike the rest of their body). If people really did seem to have perceptions – if the perceptions of others were observable in the same way their body is – then there would be no “problem of other minds” in the same way there is no “problem of other arms/legs/hands/heads/etc.” So the potential compatibility between solipsism and phenomenal conservativism is precisely why the ‘other minds’ problem exists in the first place! If you don’t understand that then you haven’t even begun to take the issue seriously (which is hardly surprising).

Secondly, this argument can be turned on its head and used to support solipsism or agnosticism.

The revised version in favor of solipsism:

If something like phenomenal conservatism is true, then since it strongly seems as if other minds are non-existent, this is good reason to believe that there are no minds except one’s own. The revised version in favor of agnosticism:

If something like phenomenal conservatism is true, then since the existence of other minds are not apparent, there is no reason one way or the other to believe in their existence.

And this is why the argument is a joke. Any argument that can be used to support all three sides of an ontological claim – realism, anti-realism, and agnosticism – is the epitome of a worthless argument. The argument takes you nowhere. All it does is re-affirm whatever philosophical convictions you held prior to encountering the argument.

But if you disagree with what I’ve written above – if you’re one of those to whom it ‘strongly seems as if there are other minds’ – then please give your definition of “mind” and lay out why there seems to be more than one of them.