 Epistêmê is the Greek word most often translated as knowledge, while technê is translated as either craft or art. These translations, however, may inappropriately harbor some of our contemporary assumptions about the relation between theory (the domain of ‘knowledge’) and practice (the concern of ‘craft’ or ‘art’). In our era, the paradigm of theory is pure mathematics, that has no obvious application to practical problems of, e.g., engineering. As well, theoretical physics sometimes has a tenuous relation to confirming/disconfirming experimentation. At the other end of the spectrum is craft, for example, carpentry, which is so enmeshed in material application that it resists any general explanation but must be learned by practice. As a consequence, theory and practice even seem irreconcilable. Outside of modern science, there is sometimes skepticism about the relevance of theory to practice because it is thought that theory is conducted at so great a remove from the facts, the province of practice, that it can lose touch with them. Indeed, at the level of practice, concrete experience might be all we need. Finally, if the practical is widened to include more than the way we manipulate the physical world but also the way we lead our lives, the relation between theory and practice has another problematic aspect. Within science, theory strives for a value-free view of reality. As a consequence, scientific theory cannot tell us how things should be or how to lead our lives. This contrast presents another aspect of the difference between theory and practice; pure theory is removed from ethical investigation and the practice of living requires it.