system
Given the following post, respond as if you're commenting on Reddit:
human
How did logical positivism persist for so long?

It seems like positivism had some serious problems that were pointed out early in its life.  For example, how can the statement "only things which are observable are meaningful" be observed to be meaningful?.  

Since this wasn't its death knell, why was it still lingering on until Quine came to put it out of its misery?  What key ideas allowed it to fight back against these pre-Quine criticisms?
gpt
The period from the classical writings of logical positivism to the publications of its supposed death knell is only thirty years, which doesn't seem to me particularly long in historical terms.

But anyway, one reason it lasted longer than one might infer it ought to have lasted, given the popular understanding of what it was about, is that the popular understanding of what it was about is mistaken.  For instance, it didn't endorse your "only things which are observable are meaningful" maxim.