Darwin feared that his theory of gradual evolution had a potentially serious flaw.
Namely irreducible complexity and the nature of mutation.
He knew that if it could be demonstrated that any organ existed that could not have possibly been formed by repeated successive iterations using slight modifications his theory would experience a complete breakdown.
Could it be safe to say that much of the scientific skepticism surrounding the theory of evolution has centered around this requirement ?
From Mivart's critisism to Margulis dismissal of gradual mutation, I think that critics of evolution have demonstrated that this criterion of failure has been established. eg.
https://michaelbehe.com;https://en.wikipedia.org/wiki/Irreducible_complexity
How do we know that biological systems could not be formed by succesive and repeated modification?
To begin with a system that is irreducibly complex cannot be produced by successive modification of a precursor system, because any such precursor is by definition nonfunctional.
We have to keep in mind that natural selection can only select a pattern that is already working.
This means that if a biological system cannot be produced gradually it would have to suddenly come into existence as a fully funtioning and integral unit for natural selection to continue its course. Simply stated its either gradual or sudden.
Goldscmidt's theory "called hopeful monster theory" which attempst to integrate "sudden appearance" with gradual mutation is replete with speculations and empty of convincing arguments. We might as well propose that the whole earth "with all of it's current features" as we know it today suddenly sprang into existence . Using luck to explaine a process is not science but metaphysical speculation.
Additionally, there is another difficulty for Darwin's theory. It's called "minimal function capability",
Not only do "all" of the parts for a irreducible system require to be present for a component to work but the part have to be made of the 1/right material and 2cd work in prescribed manner.
Unlike irreducible complexity, minimal function is hard to describe, but is an important part in a working system.
For instance:
A mousetrap requiring 5 solid parts could not work if all the parts were made of paper.
A plane could not work if the propellers turnes at 1 rpm, regardless of otherwise proper construction.
For the theory of evolution to be even fleetingly considered scientific these two issues (and others) would have to be satisfactorily resolved, they never have.
Until these and similar issues are answered, do you think that evolution should be considered a scientific fact or be relegated to the section: Fiction and fantasy? or religion and faith?
Should a person want to, what could we replace evolution with?
Belief in a divine architect and creator ?
Put it in the "Cannot be answered" folder ?
Note:
I am aware that many scientists are supportive of evolution. I am also aware that no scientist has proved it a fact.
Please do not expect me to read reams of information supporting this pseudo-science, I have already done my share of searching and reading (ad nausea) to find legitimate support for evolution.
However if you want to share information in your own words about evolution, I would appreciate that.
All the above is my opinion and is not presented with the purpose to annoy.