Brains in Vats

The recent films The Matrix (1999) and The Matrix Reloaded (2003) , starring Keanu Reeves, imagines a situation where human beings are deceived on a mass scale by artificially intelligent machines to believe that they are living a normal life. However, they are actually living in a massive hive of incubators, providing energy for the machines whilst hooked up to a virtual reality replica of the real world.

This is similar to what is called by philosophers the "Brains in Vats" argument, where it is supposed that the world as we know it is actually technologically generated and fed into our brain, which sits hooked up to wires in a vat of chemicals, devoid of a body.

Worlds of Robots, Aliens and Hollywood Executives

Other variations on this argument include the idea that human-looking machines are trying to pass themselves off as humans (Blade Runner, 1982), that the world is maintained by an alien race (Dark City, 1998) or even that a whole community of actors has been set up as a back-drop for the televised activities of one man (The Truman Show, 1998).

Whatever the plot details, the story is generally the same: systematic deception on a massive scale. Modern variations of the story have tended to include advancements in technology that would allow such deception - such as virtual reality, robotics, etc. - but the idea itself is independent of the technological means. What is important is not so much whether such a deception is possible, but how could we tell?

Witnesses and Testimony

This leads us nicely into our next topic - that of knowledge at second hand. Once again, doubt concerning this sort of knowledge can be divided into what I shall call "local" and "global" scepticism. Local scepticism concerning the statements and behaviour of other people is common: "I think he's lying", "I don't believe her", "I don't trust them".

We are quite use to being sceptical (with a small 's') about certain things: "He said he'd swum the Channel, but I was sceptical". However, so-called "global" scepticism about such things is a great deal more ambitious, and approaches the sort of scenario we come across in the films listed above.

Imagine if everyone was deceiving you all the time, would you actually know what truth was?

Exercise

Despite the unlikelihood of being in something like The Truman Show, we cannot deny that a great deal of our information comes at second hand and from distant sources. Is there any knowledge, in fact, which does not come to us from second hand sources? How much do we actually experience at first hand? As an exercise, make a list of statements of different sorts - such as, "I know the world is round", "I know Man landed on the moon", "I know grass is green" (choose about 5). Now, try to identify where this knowledge comes from. How much of it - if any - is second-hand? How much is first-hand? Which is more certain?

Once you have done this, move on to the next section.

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