That's my point, I don't expect to be able to make consistently differing observations! If his theory is correct, we still wouldn't be able to reliably exploit that feature.

I'm not saying it's wrong, I'm saying even if it's right it's useless to believe.

I mean if there is some form of reliable Psi I'll have a party because that'd be awesome.

(E.g., imagine a transhumanly intelligent agent who only hangs out with you when it knows that no one will believe that it hung out with you. This means that when it hangs out with you it can do arbitrarily magical things, but you'll never be able to tell anyone about it, because the agent went out of its way to keep that from happening, and it's freakin' transhumanly intelligent so you know that any apparent chance of convincing others of its visit is probably not actually a chance. Is this theory improbable? Absolutely. But supposing that the agent actually does hang out with you and does arbitrarily magical stuff, you don't have any way of convincing others that the theory is a posterior probable, and you'll probably just end up making a fool out of yourself if you try, as the agent predicted.

I think a problem might be when people think of psi they think 'ability to shoot fireballs' rather than 'convincing superintelligences to act on your behalf' (note that that's just one possible mechanism of many and we shouldn't privilege any hypotheses yet). If people thought they were dealing with intelligent agents then they'd use the parts of their brain designed for dealing with agents, and those parts are pretty good at what they do. Note we only want to use those parts because, at least in my opinion, psi as a relatively passive phenomenon seems to be a falsified hypothesis, or at the very least it doesn't explain a ton of things that seem just as real as passive psi phenomena.)