No, but propositions with strong counter-evidence generally are, which is the main topic here. "Not-repicable" generally means "attempted to replicate, but got results inconsistent with the original conclusion."

That is not my understanding of what “not replicable” means. My understanding is “attempted to replicate, but didn’t get any significant results supporting the original conclusion”. There’s nothing that says that the new results are inconsistent with the original findings, only that they couldn’t find any support for them in a similar study.

And that could be for a number of reasons. Of course, sometimes the results are just wrong, due to statistical flukes, or too creative data cleaning and analysis. Often the results might just be much more limited than what the original study claims: Maybe the results of a psychological study is valid for MIT students in the beginning of the semester, before lunch, but not for Yale students in the early afternoon. In this case the only mistake would have been to assume the results were universal.

This is much more correct.

It is amazing how many smart people have bad intuition on science, misunderstand the null hypothesis, etc. So much for the viability of a scientific thinking populace afaict: it seems not possible to pull off.

A very good point (I'm not sure if it's relevant to the book in question, as I haven't read it or if you're referring just about the conversation so far). It seems like many people will take a strong claim they are dubious about, and on finding the evidence is sparse, inconclusive, or missing, swing to assuming that statement is false, instead of a more neutral position of "I have no opinion or some reason to think is unlikely, but others think it is unlikely even if poorly supported or unsupported."

This tendency seems to be capitalized on fairly heavily in political media by finding some poorly supported assertion of the other side to criticize, which causes people to assume the opposite is true.

Of course not, but the more important and difficult questions address how we should reason about, evaluate, and present ideas that lack proof.

Extraordinary claims require extraordinary evidence. Or, in less dramatic terms, if you cannot reject the null, you should operate on the assumption that the null holds.

If evidence exists (failed studies) of lack of causality, is it a proof that no causality exists?

I suspect I may not be the first person to entertain this question, perhaps there is some literature on the matter.

> ...are propositions that lack proof necessarily false?

I'll have you know you just nearly nerd sniped a mathematician ;-)

Not necessarily false.

But such a small fraction of possible propositions are true that it is unlikely to be worthwhile to waste much time on propositions with no evidence.

Does this particular proposition have no evidence (none is in existence)?