This month’s issue of Popular Mechanics has an article on the latest advances in mind reading technology: using magnetic resonance imaging machines to determine without ambiguity what a subject is thinking about. As a practical matter, the main experiment cited in the article is actually not that impressive since there was a base success rate of 50 percent simply by guessing what the test subject was thinking about. As a foretaste of what is to come however, it is intriguing. As the imaging resolution goes up and the database from which the raw images are interpreted grows, the accuracy of such devices will only increase. It is well within the realm of the possible that eventually such devices may be available in a portable form.

The social consequences of perfectly accurate, reliable and widespread mind reading technology, will, as the article notes, be devastating. However, the article focuses only on the immediate usefulness of the technology as a lie detecting device and the potential abuses therein. This is of course worth considering but in my opinion, relatively straightforward. The MRI as a lie detector will become one of many technological tools available to law enforcement and will likely be regulated in the same way as such things as taps on telephone lines, DNA testing and even existing polygraph lie detectors. Its use will have to be judged against such information that can be obtained from it that society deems useful on the one hand, and offense against civil liberties on the other.

Of far greater long-term consequence are the implications of such technology on the concept of free will. It is a short jump from being able to determine what a person is thinking to being able to determine why a person is thinking a particular thought. Trace the chain of causality that underlie our thoughts and actions far enough, and you will have effectively killed free will as it is commonly conceived. Of course, in a deterministic universe, the notion of free will as completely uncaused will has always been moot, but in practice, the epistemological barrier of not being able to tell exactly what is happening inside the brain allowed to us to collectively pretend that we had free will. But now the promise of such technology allows us the possibility of one day leaping this barrier.

The Economist wrote of this in a December 2006 issue: kill free will and we kill liberalism. This goes beyond crime and punishment. For example, Google founders Larry Page and Sergey Brin were richly rewarded for having the right idea at the right time. But what if we could go into their heads and determine precisely the chain of events that caused them to have that idea, including the different influences in their lives and the people who played a part in their accumulated experiences? It would seem that given sufficiently powerful mind reading technology, individualism is diluted. If we can break down an individual, all of his thoughts, memories and actions into chains of cause and effect that interconnect with everyone else, what would be left, if anything, of the individual as a unique being?

All of this will not affect society for a long, long time, but it would be wise to think about the future. In the nearer term, it would be interesting what effects such technology will have on religious belief. The black box of human consciousness has long been the last redoubt of theologues against the all encompassing power of science and reason to explain everything that exists. And what if we could read the minds of the religiously inclined to see if there is any rational justification for their beliefs? Now, that will be an exciting experiment.