Quite the specious little syllogism you have here. If you weren't so busy patting yourself on the shoulder for your brilliance, you may notice that you are forcing together two different meanings of "change", one pertaining to biology and the other to absolute, disembodied logic.
If we but give a more precise definition of evolution, your little semantic construction falls down like a house of cards. Observe:
The apparition of genetic mutations is a constant of organic life-forms. If one such mutation provides a better adaptation to the environment a given life-form exists in or to changes of said environment, improving the chances of survival of the carrier of said mutation, it is highly likely that it will be passed to following generations, eventually spreading to most or all of the species.
On a side note, while individuals will presenting genetic mutations will appear constantly, a species as a whole can encounter periods of "evolutionary calm", where, due to a good adaptation of the species to its milieu and to a stable ecosystem, additional beneficial mutations do not provide enough of an advantage to the mutant subject to allow his genetic material to be spread widely. So no, species-scale change isn't constant. But since no ecosystem can remain stable forever, these periods of "evolutionary crawl" are likewise necessarily finite: be it a meteor strike, a major climatic change (ice age, for example), a new predator appearing, a threat to the primary food source of the species or whatever, sooner or later the balance will be disrupted and the species will have to adapt (evolve) or die.
Survival of the fittest does not apply to Physical Characteristics. Problem no. 1. Plus we also observe survival of the luckiest and even survival of the weakest in nature. That works against that one.
Not that I'm dissing on Natural Selection because its an important process to Science. However, what I will say is its actually contra Evolution! Natural Selection is a consistent process, while Evolution, being something regarding Change, resulting from NS+RM, we'd expect a whole lot of deformed looking people if Evolution were truly true. So from a practical standpoint it does not work either.
Now on your other point about Logic, if Science doesn't conform to Logic, then its Illogical, plain and simple. Logic is a Universal (give me an example where it doesn't apply). If Science is illogical than I may as well just throw it right out the window, because it does not correspond to reality. That also includes Biology. If I am to be consistent here with a Biological function, lets say food for instance and the digestive system. If the digestive system does not work as according to Logic, and it starts doing goofy things, then I am going to have to go see a doctor, or I will die. If I get sick from eating food, is it ever my digestive system's fault? No, its food poisoning. So again, the Biological function regarding the digestive system has to be a consistent function and correspond to Logical processes or the next step in the process is not going to be a positive result.
Logic corresponds to reality, otherwise we may as well be living in a madhouse. We could both be going to the grocery store and not be going to the grocery store at the same time in the same sense.
