From what I've studied, I'll simply say that philosophical clarification feeds the rational handling of biological data by various scientists, so they are doing 'science' and not just philosophy. Moreover, science, especially that which addresses the evolution of organisms, utilizes all kinds of 'science' to bring together the conclusions that we now know of as the Modern Synthesis (or even the Extended Modern Synthesis).
The basic point is that philosophy of some kind is present and used within the overall corpus of theories, methods, and practices of science as it all relates to the theory of evolution. Science isn't just the 'raw data': science includes what you DO with the raw data as well, among other things.
Also, when you speak of a "power source" randomly driving the evolutionary process, you do involve some philosophy to form the theory, but as T. Ryan Gregory (2009) points out the following:
Mutation is random with respect to fitness. Natural selection is, by definition, non-random with respect to fitness. This means that, overall, it is a serious misconception to consider adapatation as happening "by chance." (p. 162)
Reference
Gregory, T. R. (2009). Understanding natural selection: essential concepts and common misconceptions.
Evolution: Education and Outreach,
2(2), 156-175.
[The above reference is one of the sources I used in my graduate work ... so you might find it handy.]