Or put another way, mind is to brain what computer software is to the computer's hardware. This view is called "functionalism." In 1980 philosopher John Searle published an argument that sought to show that functionalism is wrong and that there's more to our cognitive experience than simple computation. His argument came to be known as the Chinese Room argument and neuroscientist Michael Egnor has a helpful discussion of it at Evolution News and Views. Egnor describes the argument as follows:
Imagine that you are an English speaker and you do not speak Chinese. You've moved to China and you get a job working in a booth in a public square. The purpose of the both is to provide answers to questions that Chinese-speaking people write on small pieces of paper and pass into the booth through a slot. The answer is written on a small piece of paper and passed back to the Chinese person through a separate slot.In other words, the computer, like the person in the booth, has no understanding of what it's doing. As Egnor says: Thought is about understanding the process, not merely about mechanically carrying out the matching of an input to an output according to an algorithm.
Inside the booth with you is a very large book. The book contains every question that can be asked and the corresponding answer -- all written only in Chinese. You understand no Chinese. You understand nothing written in the book. When the question is passed through the slot you match the Chinese characters in the question to the identical question in the book and you write the Chinese symbols corresponding to the answer and pass the answer back through the answer slot.
The Chinese person asking the question gets an answer that he understands in Chinese. You understand neither the question nor the answer because you do not understand Chinese.
Searle argues that you are carrying out a computation. The booth is analogous to a computer, you are analogous to a CPU, and the information written in Chinese is analogous the algorithm. The question and the answer written on the paper are the input and the output to the computer.
Searle's argument denies that computers "think." They simply follow an algorithm. Since we do think, however, and we do understand, either our brains are not computers or functionalism is not true.
Searle points out that the computation performed by the booth and its occupant does not involve any understanding of the questions and answers provided. His point is that computation is an algorithmic process that does not entail or require understanding, but since we do understand when we perform a computation, human cognition is something qualitatively different from mere computation.