"A thing is not proved just because no one has ever questioned it. What has never been gone into impartially has never been properly gone into. Hence scepticism is the first step toward truth. It must be applied generally, because it is the touchstone."In Diderot's time, the question of what caused fire - liberation of phlogiston or something else - was a live debate in science. The existence of the luminiferous ether was a live possibility all the way up to the early 19th Century. An open mind, impartially considering both theories, was proper in his time.- Denis Diderot (1713 - 1784)
There have been many other scientific questions that were unresolved in the past, and an open mind that impartially considered all competing theories was indeed the proper approach.
As recently as 100 years ago (50 years after Origin of the Species), evolution was still being vigorously challenged by other theories of origins. But today, 100 years later, the debate is over. Deal with it the way that the proponents of phlogiston dealt with it. (How did the phlogiston activists deal with oxygen anyway?)
Or to put it another way, "evolution is a theory in crisis" is soooo 100 years ago.