Friday, February 16, 2007


Not to be confused with being materialistic, materialism is defined to be the doctrine that matter is the only reality, and that everything in the universe, including thought, will, and feeling, can be explained only in terms of the physical. A natural question which arises from this is how exactly to deal with the existence of one's consciousness.

A recent Time article by Steven Pinker discusses this topic and remarks on how scientists are systematically uncovering new secrets regarding the human brain. It's a fascinating read and makes a number of interesting points. In summary, neuroscientists have reason to believe that every aspect of consciousness can be tied to the (physical) brain.

Consider, if you will, the Star Trek transporter beam. Let us assume hypothetically that we will eventually develop this technology. The transporter beam works by reading your molecular makeup, dematerializing your body into "energy", and finally rematerializing your body at some other location. This whole process presumably occurs close to the speed of light and is thus a very efficient method of transportation.

The problem with this technology is that it seems to naturally allow for the ability to duplicate humans (this was used as the plot device to motivate the Star Trek TNG episode Second Chances) by simply failing to dematerialize the original. In this case, there now exists two copies of the same person. Since these two people are indistinguishable from each other and carry with them the exact same past experiences, they will both believe they were the original person before using transporter beam.

The problem runs even deeper once you consider the original intended use of the transporter. The transporter is supposed to dematerialize the original copy of the person. That is to say, the transporter beam creates an identical copy of a person somewhere, and then kills the original.

So there's the dilemma. When you get transported, you die and an exact copy of you gets created somewhere else. Functionally, it appears as if you were indeed transported from one place to another, so it doesn't matter to society which copy lives and which dies. But the fact remains that you yourself don't actually get transported, but are replaced with a new person who is identical to you in every way. This of course leads to a number questions regarding the definition of life and self and so forth, which was the entire point of considering this scenario in the first place.

Materialism suggests that your consciousness is simply the result of chemical and electrical activity within your physical brain. The essence of your being is a blueprint that, given the proper technology, is easily copyable, just like any piece of software. If we find this view plausible, then we must reject the notion of having what many call a soul. Taking this another step further, we must also reject the existence of an afterlife.

Though this seems to be a particularly radical line of reasoning, it actually has very little impact on your everyday life. In fact, as soon as you accept this argument of materialism, you can then proceed normally as if this argument didn't exist. I'm also of the opinion that free will is an illusion (i.e. not due to some fundamental notion randomness within our universe). But again, as soon as you accept this, you can effectively ignore it almost completely. Functionally, everyone still reduces to the same kind of selfish agents they were before accepting this argument.

The biggest change required is to reject any religious notions of an afterlife. This, I think, is a good thing. As Steven Pinker so aptly pointed out, believing in an afterlife necessarily devalues this physical one, and "nothing gives life more purpose than the realization that every moment of consciousness is a precious and fragile gift."

In the long run, of course, I want to live forever.


Jerry Talton said...

Dude, that's easy!

Yisong said...

That is site is almost as informative as the Time Cube.

Trevor Goodchild said...

"Materialism suggests that your consciousness is simply the result of chemical and electrical activity within your physical brain. If we find this view plausible, then we must reject the notion of having what many call a soul."

You've basically said nothing here. You've said "X implies Y. Thus, if we accept X, we get Y." Here's a similar argument:

"Christian dualism suggests that your consciousness is simply the result of metaphysical activity within your physical brain. If we find this view plausible, then we must accept the notion of having what many call a soul."

Stop being a bigot for science and start learning to think scientifically!

Yisong said...

I'm not sure I follow your argument. In the excerpt you're referring to, if I try to map my words to logical statements, I get the following two implications:

"materialism" implies "consciousness is a physical process"


"consciousness is a physical process" implies "we don't have souls"

I don't detect any circular reasoning here. Perhaps I should've phrased things differently, so let's give it another try. Suppose we take materialism as axiomatic, then it seems to follow that we must reject the existence of souls.

Perhaps you think this result is unsurprising, but I personally found it counter-intuitive when I first encountered it. I instinctively wanted to believe that I have a soul. But once you consider various plausible scenarios (such as the transporter beam one that I used), you start to see some fuzzy evidence supporting the logical consequences of materialism.

The striking weakness of this line of reasoning is this dependence on non-obvious axioms (such assuming materialism to be true). There may be other axioms we can use which also logically imply the situation we find ourselves in when we consider the transporter beam scenario. As with virtually every scientific theory, we can only measure the consequences, but not the theory itself. We all learned from a young age that empirical evidence can only disprove, but never prove. But such is life.

Now if we assume (dangerous!) that the evidence in support of a particular theory or axiom is (mostly) uncorrelated, then we can start to derive fairly tight probabilistic bounds regarding how confident we are on the correctness of said theory or axiom. An additional approach (and a popular one at that) is to use Occam's Razor, which basically states that, all other things being equal, the simplest solution tends to be the correct one. One probabilistic interpretation of Occam's Razor is to impose a non-uniform prior distribution on the space of axioms which satisfy the evidence (e.g., placing more probability mass on the simpler axioms). This is in fact one of the core problems within machine learning, which is the field I study. One can view machine learning as an attempt to automate at least a portion of the scientific method. But alas, I see that my ramblings have taken me way off topic.

Navreet said...

Couldn't agree more