In this paper I try to elucidate the differences between theoretical and practical endeavors in philosophy, and then to show that in a sense philosophy has to be theoretical, but— if it claims to be viable—it must be practical as well. First I consider the meaning of the terms theoretical, practical, abstract, and concrete. Then, with the help of Whitehead’s ideas on this topic, I briefly reflect on the method, aims and role of philosophy. I hold that a properly established (...) philosophical approach should have its roots in concrete experience and should include concrete applications. Thus, abstract ideas can be (and indeed often are) transformed into our daily life practices, being applied to solve real problems—personal, social, environmental, etc. The ideas are conveyed from the sphere of philosophy to that of ordinary life. In the next stage I demonstrate this principle using a concrete example, Whitehead’s philosophical system and how it can be fruitfully applied to the sphere of deep ecology. There are many other examples that could be mentioned, but giving a proper demonstration of this application principle requires more space and so I concentrate only on one of these examples. (shrink)