I feel that there is utility in maintaining a distinction between 'internal' and 'external' approaches to practice, especially for the beginner. However, one must keep in mind that 'harmonizing' oneself dissolves all such distinctions... regardless of utility. At this point we are then simply talking of the level of 'refinement' of awareness in ones practice.
For an overview of the distinction, here's a start...
Neijia and Waijia
