I saw this claim awhile back and it got me thinking and it’s actually half-right. Evolution is a philosophy. Not an atheistic religion or ideology bent on dominating and destroying christianity etc etc as creationists often claim, but there are many instances where people assume something happened for darwinian reasons without actually testing it, or where it cannot be tested. However this is not unreasonable, and here’s why.
If you go to a doctor and they look you over and find you have a fever, they will take that as a sign that you probably have an infection. No doctor is going to reinvent the wheel and re-test the hypothesis that infections cause fevers every time one of their patients has a fever. Similarly once it’s accepted that species do change via natural selection any change can be reasonably believed to likely be caused by natural selection or other evolutionary mechanisms, though this is not technically scientific. So if zoologists spot fish becoming small enough to fit through the fishing nets of commercial fishermen, they may attribute this to natural selection. They’re not going to re-test the hypothesis that fish evolve any more than a doctor is going to do a study on every patient with a routine symptom – if they did nothing would ever get done. But if anyone thinks evolution is just a philosophy and is not at all scientific (ie is based on logic and inference alone without experimental tests) then I humbly urge you to google “evolution experiment” some time and see how wrong that statement is.
I googled it and the first hit is this page on wikipedia about biologists watching 12 identical strains of e. coli bacteria for 50,000 generations and how some evolutionary adaptations have occurred in all 12 strains, but some have occurred in only one or a few etc.
Evolutionary thought can be philosophical or speculative at times (especially in fields of study peripheral to genetics or biology), but it is definitely a science. And a damn good one too.