CrimePsych

Steven Pinker, in this particularly early chapter in his book, scrutinizes briefly a range of theories around the age old mind-body problem, which in turn leads us into Alan Turing and Turing machines The motivation behind discussing these is to give us an adequate launch point to discuss the computational theory of mind.

The main dilemma facing the mind-body problem is that of interaction, and how a nonmaterial entity could possibly interact causally with a physical object. There are other dilemmas too; like the overwhelming evidence that the mind is the activity of the brain and how drugs and alcohol could affect and infringe on a non-physical thing. Subsequently the argument behind this particular theory of mind is fragile at best and we must contemplate alternatives that have stronger premises and make more sense.

Around the middle of last century a mathematician named Alan Turing helped break the Nazi enigma code in WWII, and more to the point, designed a hypothetical machine that used symbols and a set of predefined procedures (i.e. an algorithm) that when followed would produce the solution to a given problem in a finite amount of time. This machine was eventually called a Turing machine, and a thesis known as The Church-Turing thesis emerged alongside it.

A Turing machine consists of only a few elements; a read-write head that can read and write symbols, a tape that is divided into unique cells of a predetermined size, a pointer, and a set of mechanical reflexes. Without going into specifics, it was discovered that one could create a universal Turing machine that was able to impersonate the actions of any other Turing machine simply by feeding a description of said Turing machine into it. In this way, Alonzo Church, was led to conclude that any well defined set of instructions or steps that was guaranteed to deliver a solution could be implemented on a Turing machine.

But what does all this have to do with our theory of how the mind works? A Turing machine, although a hypothetical device, showed us how our mind may work and led Pinker to propose the idea of the language of thought, mentalese, and how this is an integrated and integral part of the computational theory of mind. He systematically shows and explains how the popular misconception that we think in our native tongue is wrong, and how a richer language is at work in our minds.

A good analogy for those who know how a computer and its software work would be to consider mentalese as the programming language. Within this language we have representations that are sets of symbols and correspond to aspects of the world, while the homunculus could be thought of as sub-programs or modules within our software. These modules are only required to respond to a small number of symbols, and subsequently the system becomes a lot simpler. As Pinker says “The intelligence of the system emerges from the activities of the not-so-intelligent mechanical demons inside it.”

The computational theory of mind thus has two key elements, our mental representations and the processes or programs (sometimes called demons) that access them. As Pinker states, any complete theory of psychology needs to take these into consideration and explain their use. If a task is considered more difficult than another is it likely that it uses a lot more symbols or simply requires a longer chain of demons to complete it. The way in which we generalize from experience, or react to different situations that may be similar to others is indicative of our use of representations.