Why philosophical zombies matter

I first wrote about the mysteries of consciousness on this blog back in February 2006. This prompted me to do some reading on the philosophy of mind, and in March 2006 I wrote more about consciousness.

Though I didn't mention it directly in that post, a very compelling argument concerns what are called philosophical zombies. I would put the argument like this. First, ask yourself: Is it conceivable that there could be a thing that appears to be human but in fact has no conscious experience? In other words, a biological machine, identical to a human in every way, except that it has no free will, feels nothing, experiences nothing. To put it bluntly, a zombie.

If your answer is no, then I would ask this: How can you know that some of the "humans" around you are not in fact zombies? Is there a device available that will measure consciousness? Granted we have tools that can measure aspects of the complex electrical and chemical activity in the brain. But complex electrical and chemical activity is not consciousness. Consciousness has to be experienced. And there's the rub. We can be sure of only one person's consciousness: our own. As Descartes famously noted, "I think therefore I am". Continuing to follow this line of reasoning can lead to solipsism, but that's not my point at all. Rather, I believe that the philosophical zombie argument provides one indication that there is more to the world than the material.

In response to this argument, people will sometimes steadfastly maintain that consciousness is nothing more than complex neurological activity. When I point out that there's no reason to believe that such activity has to be accompanied by consciousness, the response has sometimes been to deny consciousness itself! Which brings me back to the cartoon at the start of this post. Someone who denies their own consciousness could only be a zombie!