You're assuming that controlled experiments are the only 'truly-scientific' method of experimentation, and that's not true. Case studies, controlled experiments and systematic observation etc. are all part of the scientific method and all have their advantages and disadvantages. Granted, the lack of controlled experiments, as you correctly said, is a weakness of evolutionary biology, but the method is still scientific; hypotheses are still created from observational data, more data is collected that falisfies/supports this hypothesis, and the hypothesis is refined until a theory is developed. It's still the same process, just by different means. Also, you do not 'prove' a hypothesis - you support it; it is impossible to prove a hypothesis.PhiMed said:First, the method at which it was arrived is not, strictly speaking, the scientific method. In the scientific method, an hypothesis is formulated, then a test of that hypothesis is constructed to observe the variable in question, data is collected, and it is proven or disproven.
Evolutionary biology works in the opposite direction. In evolutionary biology, data is collected and compiled, and an hypothesis is formulated afterwards. If subsequent data disprove this explanation, the explanation is revised, but there's no way to devise a controlled test, because you can't hold any of the environmental variables constant. For this reason, evolutionary biology would probably better be described as a "logic system" than a "science". This doesn't mean it's not true. It just means it isn't truly scientific. The same could be said for certain aspects of astrophysics, but enough is actually scientific that we can forgive them that.
What I think is the reason behind people not believing in evolution is the word 'theory'. The scientist's definition of the word 'theory', and the layperson's definition of the word 'theory' are very different. We use 'theory' in everyday life to mean something we admit we have no evidence for, but that's what we think happens...but in science, it's quite the opposite. A scientific theory will have plenty of evidence to back it up. Ever heard the Creationist argument 'Evolution is only a theory'? That is what I'm getting at.
Apparently, there is so much evidence for Evolution that it outweighs any other scientific theory to date, and it should really be called the 'Law of Evolution'. That would solve this little problem with the word 'theory'.