Thinking and Computation - Thinking as Computation - page 2

Using what we believe or know in this way is so commonplace that we only really
pay attention to it when it is not there. When we say that someone behaved unintel-
ligently , for instance, when someone uses a lit match to see if there is any gas in a
car's gas tank, what we usually mean is not that there is something the person did
not know but rather that the person has failed to use what he or she did k n ow. We
might say: “You weren't thinking!” Indeed, it is thinking that is supposed to deliver
what we know to the decisions we need to make. The students head toward the door
because they think that is the way to free pizza. It is thinking, in the end, that makes
human behavior intelligent.
But what is thinking, and how does it work? What exactly goes on in people's
heads when they think about where to go for free pizza, or about who will win the
Academy Award for Best Actor, or about whether a free market needs to be regulated?
The purpose of this topic is to suggest where to look for an answer. It proposes that
thinking is a form of computation. In the same way that digital computers perform
calculations on representations of numbers, human brains perform calculations on
representations of what is known.
This chapter is an introduction to this idea. The first section reviews very briefly
the notion of thinking. The process of computation is somewhat less familiar, so more
time is spent on it, in the second section. The third section introduces the (somewhat
controversial) idea of thinking as a form of computation.
1.1 Thinking
Are brains like computers? In a word, no . It is true historically that in trying to
understand the brain, people have proposed models that seem to mirror the most
advanced technology of the time. Over the years, the brain has been described as
clockwork, a steam engine, a telephone switchboard, and (these days) a computer.
But in time, these descriptions are found to be much too simplistic to say anything
useful about what is inside our heads. There is no reason to believe that the computer
analogy will be any different in this regard.
In fact, this topic has very little to say about the brain itself. Rather it focuses on
thinking. But thinking is what the brain does. How can one study the relation between
computers and thinking without studying the brain?
Here is a useful analogy. Consider the study of flight (in the days before airplanes).
One might want to understand how certain animals like birds and bats are able to fly.