Voila indeed. But I'm not doing metaphysics, not even of the Presocratic variety. I'm not doing logic either, or psychology, or ethics.
This is an interrogation. Yes, detective work. The logician and the metaphysician ask, 'What ought I to believe? What do the arguments prove?' (Remember Plato, 'following the argument wherever it may lead.') I don't give a rat's arse about what I 'ought' to believe (in the legalistic sense of 'ought' which only a philosopher would 'understand').
My concern is with what I can and do believe. This is real life, this is serious. (Remember, we're not talking about religious belief. I'm not trying to 'better' myself.) It's about what it is possible to believe, if anything is possible to believe (if 'belief' isn't a totally decadent notion).
'There's the part where you say it, then there's the part where you take it back' (Austin; see Glass House Philosopher notebook I, page 12). Quite. OK, a detective needs something to interrogate. Sounds like Derrida territory, except that I have a total disgust of sniffing other writers' literary diarrhoea. I'm no Husserl either (interrogating 'experience').
All that's left is myself. Only not in a psychological way. More like trying beliefs theories, if you like, maybe speculations though that doesn't quite capture it on for size. To see if they fit. 'The world is, and will always remain absolutely other than I.' That means, I am not a mere part or function of the 'world', I didn't come from the world, the world didn't 'make' me. Maybe I made the world? But then the world wouldn't be truly 'other' would it? (You and I and they are all manifestations of the one 'Being' or 'It' playing hide-and-seek with itself. Blechh!)
So: WHAT, if anything, is it possible for me to believe? about myself? about the world?