Technique is the aspect of an actor's work that enables him to perform reliably and consistently night after night.
Yes, some people do get there faster, but it can be achieved by anybody, given enough lifetimes! This just means that hard work has to be done. This shouldn't discourage the student actor, it should inspire him.
Technique can be more than a soulless mechanical asset, however. An increase in technique also opens up more possibilities for expression in the same way that learning the meaning of a new word fills ones head with new ideas. And technique doesn’t only reach out to allow new expression; it also reaches in and releases content.
Eventually technique must be assimilated into the me-myself, buried in the subliminal, transcended, made the servant of the artistic intention. The more rigorous the technique being learned, the more difficult this is to achieve. Actors who display a conscious intellectual control of their work seem not to trust that they have absorbed their technique, and the effect is stiff and wooden.
In educating the actor, one must pursue a balanced approach to technique. Although technique builds reliability and actually opens up expressive possibilities, too much emphasis on it can present the individual student with an insurmountable barrier. The danger is not that the student can't eventually learn technique; it is more that he can't learn to transcend it. It is always a good idea to keep technical exercises tied to expressive and communicative values.
Too much focus on technique can also present problems later in an actor's career. Male actors in their thirties, and female actors in their fifties often appear to become overly preoccupied with craftsmanship, and become more "nuts and bolts" in their approach at the expense of joy and playfulness in their acting. In an often defensive way, it becomes their primary source of pride in their work. "At the very least, I can do my job well!"
However there are times when a narrow focus on technique is valid. Extreme technical virtuosity is a special case in which the "medium becomes the message," in the sense that the virtuosity itself asks provoking questions about the human condition, about what is humanly possible. Technique becomes both the means and the end. But one sees this more often with musicians and dancers. Generally, western actors are notoriously lazy at maintaining their technique.
Somewhat ironically, considering how it and its derivatives are now often referred to as techniques, Method Acting was a reaction against the “technical” actor. In post-war New York, where Method Acting first took root, Art was celebrated as an explosion of personality. Indeed it took more personality than technique to ride a bicycle across a canvas of wet paint. English actors of the time were criticised for being too cold and technical!
It is a common mistake to confuse a method for teaching acting with an actual technique of acting.