He is able to respond to given cues, and can, within limits, adapt and learn. I am a chameleon. Sellers plays Chance as a man at peace with himself. When the old man dies, the household is broken up and Chance is evicted, there is a famous scene where he is confronted by possible muggers, and simply points a channel changer at them, and clicks. He is surprised when they do not go away.
Sellers plays Chance at exactly the same note for the entire film.
He is detached, calm, secure in his own knowledge, unaware of his limitations. Soon the rich man grows to treasure his reassuring friend. It has the appeal of an ingenious intellectual game, in which the hero survives a series of challenges he doesn't understand, using words that are both universal and meaningless. If Chance's little slogans reveal how superficial public utterance can be, his reception reveals still more. But this leads to a directness than can be mistaken for confidence, as when he addresses the president by his first name, or enfolds his hand in both of his own.