Stanislavski's system is a systematic approach to training actors that the Russian theatre practitioner Konstantin Stanislavski developed in the first half of the 20th century. Stanislavski was the first in the West to propose that actor training should involve something more than merely physical and vocal training. His system cultivates what he calls the "art of experiencing" (with which he contrasts the "art of representation"). It mobilises the actor's conscious thought and will in order to activate other, less-controllable psychological processes—such as emotional experience and subconscious behaviour—sympathetically and indirectly. In rehearsal, the actor searches for inner motives to justify action and the definition of what the character seeks to achieve at any given moment (a "task").
Later, Stanislavski further elaborated the system with a more physically grounded rehearsal process that came to be known as the "Method of Physical Action". Minimising at-the-table discussions, he now encouraged an "active analysis", in which the sequence of dramatic situations are improvised. "The best analysis of a play", Stanislavski argued, "is to take action in the given circumstances."
Thanks to its promotion and development by acting teachers who were former students and the many translations of Stanislavski's theoretical writings, his system acquired an unprecedented ability to cross cultural boundaries and developed an international reach, dominating debates about acting in the West. Stanislavski’s ideas have become accepted as common sense so that actors may use them without knowing that they do.
Many actors routinely equate his system with the American Method, although the latter's exclusively psychological techniques contrast sharply with the multivariant, holistic and psychophysical approach of the 'system,' which explores character and action both from the 'inside out' and the 'outside in' and treats the actor's mind and body as parts of a continuum. In response to his characterisation work on Argan in Molière's The Imaginary Invalid in 1913, Stanislavski concluded that "a character is sometimes formed psychologically, i.e. from the inner image of the role, but at other times it is discovered through purely external exploration."