Richard Carrier on solipsism, but not nearly as pithy:

Solipsism still requires an explanation for what you are cognating. There are only two logically possible explanations: random chance, or design.

It’s easy to show that the probability that your stream of consciousness is a product of random chance is absurdly low (see Bolzmann brains, for example). In simple form, if we assume no prior knowledge or assumptions (other than logic and our raw uninterpreted experience), the prior probability of solipsism becomes 0.5 but the likelihood of the evidence on solipsism is then vanishingly small (approaching zero), since chance events would sooner produce a relative chaos than an organized stream of complex consciousness, whereas the likelihood of that same evidence on a modest scientific realism is effectively 100%. Work the math and the probability of chance-based solipsism is necessarily vanishingly small (albeit not zero, but close enough for any concern). Conclusion: random solipsism would sooner produce a much weirder experience.

That leaves some sort of design hypothesis, namely your mind is cleverly making everything up, just so. Which requires your mind to be vastly more intelligent and resourceful and recollectful than you experience yourself being, since you so perfectly create a reality for yourself that remains consistent and yet that you can’t control with your mind. So you control absolutely everything, yet control next to nothing, a contradiction in terms, although an extremely convoluted system of hypotheses could eliminate that contradiction with some elaborate device explaining why your subconscious is so much more powerful and brilliant and consistent and mysterious than your conscious self is. The fact that you have to develop such a vastly complex model of how your mind works, just to get solipsism to make the evidence likely (as likely as it already is on modest scientific realism), necessarily reduces the prior probability by as much, and thus the probability of intelligent solipsism is likewise vanishingly small. Conclusion: intelligent solipsism would sooner result in your being more like a god, i.e. you would have vast or total control over your reality.

One way to think of the latter demarcation of prior probability space is similar to the thermodynamic argument against our having a Boltzmann brain: solipsism is basically a cartesian demon scenario, only the demon is you; so think of all the possible cartesian demons, from “you can change a few things but not all,” to “you can change anything you want,” and then you’ll see the set of all possible solipsistic states in which you would have obvious supernatural powers (the ability to change aspects of reality) is vastly larger than the set of all possible solipsistic states in which you can’t change anything except in exactly the same way as a modest scientific realism would produce. In other words, we’re looking at an incredible coincidence, where the version of solipsism that is realized just “happens” to be exactly identical in all observed effects to non-solipsism. And the prior probability space shared by that extremely rare solipsism is a vanishingly small fraction of all logically possible solipsisms. Do the math and the probability of an intelligent solipsism is vanishingly small.

This all assumes you have no knowledge making any version of solipsism more likely than another. And we are effectively in that state vis-a-vis normal consciousness. However we are not in that state vis-a-vis other states of consciousness, e.g. put “I just dropped acid” or “I am sleeping” in your background knowledge and that entails a much higher probability that you are in a solipsistic state, but then that will be because the evidence will be just as such a hypothesis would predict: reality starts conforming to your whim or behaving very weirdly in ways peculiar to your own desires, expectations, fears, etc. Thus “subjective” solipsism is then not a vanishingly small probability. But “objective” solipsism would remain so (wherein reality itself is a product of your solipsistic state), since for that to explain all the same evidence requires extremely improbable coincidences again, e.g. realism explains why you need specific conditions of being drugged or sleeping to get into such a state, and why everything that happens or changes in the solipsistic state turns out not to have changed or happened when you exit that state, and why the durations and limitations and side effects and so on all are as they are, whereas pure solipsism doesn’t come with an explanation for any of that, there in that case being no actual brain or chemistry or “other reality” to return to, and so on, so you would have to build all those explanations in to get objective solipsism to predict all the same evidence, and that reduces the prior. By a lot.

There is no logically consistent way to escape the conclusion that solipsism is exceedingly improbable.