Skepticism / Solipsism
I think two fundamental errors are made when debating this issue: 1) Making fun of the matter- which usually results in the discussion ending and no conclusion being made (I’m sorry but I have tried discussing this many times and really want an answer now) 2) Expecting the claimant to have an answer that explains reality otherwise. We have to realise it’s not ‘we are brains in a vat’. It’s ‘we could be brains in a vat’ and ‘we have no way of proving otherwise’