But it is quite erroneous to suppose that these problems therefore mean that Darwinism has no scientific credibility. Scientists themselves constantly argue about the various parts of the theory, adjust it, refine it, come up with competing versions of it, and so forth. In fact, that is one of the most interesting areas of modern biology. The idea that a single problem or series of anomalies disqualifies a scientific theory indicates that those making such a claim have little idea what science, in fact, is or how it is carried out. A theory in which there are no such problem areas is generally of very little interest to scientists.
Newtonian mechanics has serious problems, too.
Since evolution cannot be observed because the time spans are too long, therefore it cannot be scientific. This, of course, is the old logical trick of setting up a self-serving definition. Scientific theories deal all the time with things we cannot observe, like, gravity, electrons, electric fields, viruses, and so on. On the basis of these theories predictions are made which lead to observable results which will enable the theories to be confirmed or falsified. In this sense, evolution is thoroughly scientific.