Definition
"Act as if" is the practice of behaving in accordance with the self-image you are trying to install, before the feelings have caught up. You act calm when you do not yet feel calm; you act competent when you do not yet feel competent; you act generous when generosity does not yet feel automatic. The behaviour is the lever; the feeling is the lagging indicator.
Maltz drew on Alfred Adler and William James for the technique. Both observed that emotion often follows expression, not the reverse — that smiling produces a small amount of cheer, that holding a confident posture produces a small amount of confidence.
Why it matters
How it works
Pick the self-image you want to occupy — calm, generous, competent at this kind of work — and identify two or three concrete behaviours a person with that self-image would do today. Then do them. Not perfectly; just observably. The nervous system reads the behaviour as evidence, the self-image shifts by a small increment, and the next round of the same behaviour comes easier.
Maltz was clear about the distinction from delusion: this is not pretending to already be what you are not. It is rehearsing the future state under realistic conditions. The behaviours have to be real, the situations have to be real, and the results have to be examined honestly. Over time, "acting as if" becomes "being" — not because the original act was fake, but because the act was the training.