[webstrand]

I do agree with you: one can absolutely apply the scientific method to their own mind, the subjective experience of consciousness is a largely consistent source of information, and that's all you need for the scientific method. Applying those discoveries to other people is unlikely to be correct. But you're arguing a tautology, you've already accepted the axiom of other minds, and you're working backwards from that premise to find evidence supporting the axiom.

The point of solipsism isn't to actually reject other minds. I'd argue that's quite a useless belief to hold, it provides no predictive power and no additional ways to engage with the world around one self. But there are any number of other equally valid interpretations of the only evidence one has access to: the fact that you yourself are conscious and that you receive input from a remarkably consistent source of information.

Not all of those interpretations provide the same tools of thought, but some are equivalent in power: For instance you could reject other minds and instead posit that your perception of them is a sophisticated construct created by your own consciousness to simulate interaction with a complex and consistent world. Alternatively, you might consider that other minds are simply facets of your own mind, reflecting your subconscious processes. These constructs are similarly axiomatic, they're unfalsifiable.

A lot of the rest of your argument feels like a straw-man to me. I don't fundamentally disagree with you—I also accept the existence of other minds because it provides predictive power and useful tools of thought. But writing-off people who question this axiom as "irrational", you're just defining "rationality" to include the axiom of the existence of other minds. And "irrational" is a loaded term when used to describe a person or their beliefs.