They can simulate mental activity, but not duplicate it. Searle's Argument Premise 1. Computer programs are formal or syntactic . Human minds have mental contents or semantics . Syntax by itself is neither constitutive of nor sufficient for semantics.
Computer programs are neither constitutive of nor sufficient for mind.
Imagine that you understand absolutely no Chinese, but are locked in a room and given a set of English instructions for manipulating strings of Chinese characters. Using the instructions you have been given, you take strings of Chinese characters which are slipped to you under the door and produce a new string of Chinese characters which you slip under the door to those waiting outside. The scale of Searle's example is misleading. For the set of instructions to be analogous to the brain's program would require enough books to fill the room from floor to ceiling. The neurons in a brain do not understand English any more than the individual in Searle's Chinese Room understands Chinese.