Determinism, Computability, Observer EffectPosted: June 7, 2010
I am reading a fascinating book, The Emperor’s New Mind, by Sir Roger Penrose. In the book, he has very forcefully brought out the idea that the deterministic view of science, developed over the past five centuries, taken to an extreme area by those supporting Artificial Intelligence as a viable alternative to Human Intelligence, is largely misplaced, and that while there are certain aspects which are deterministic in nature, there are many others which are not and even others which are not computable even though deterministic.
Whats the difference? To my understanding, deterministic is the property of a system which tells us that there is some logic, or rule, or algorithm by which given the current styate of the systesm (in sufficient detail, lets add for good measure), the stateof the system at another point, in space, time, or both, can be determines. Computability, on the other hand, is the property which defines the possibility of this determinism being carried out. In some scenarios, this may not be possible to compute because there may be operations which are mathematically not possible, for example, division by zero. Thats a basic one (and the one I understand), though I am told there are others.
The question of determinism and computability apart, because not what I think I am writing about (though with topics like these ones, can never be sure), what I am writing about is my own puny interpretation of the observer effect. For those not familiar with that (either definitionally or conceptually), let me juwst mention the scenario has has described:
In a two-slit experiment, one possibility to describe the interference effect could be the photons of light get split (or maybe the vibrations of the wave function do, I am not quite sure which … or shall we say I am uncertain which?) and each part goes through one of the slits. This can be found out using particle detectors, which would be able to observe either full or non particles. However, if a particle detector is placed at one of the slits, so the observer can see which slit the electron or photon went through, the interference pattern disappears. For the interference to happen, there must be a lack of knowledge about which slit the electron went through. In other words, an observer, by his very presence can make the experiment unfeasible.
Interesting, this. Lets look at this in detail. Who is the observer here. Or rather, what is the observer here? The particle detector. And what is the cause behind the particle detector being there? The cause was human. So, shall we say that the observer in this scenario is human? If we were to say that, then we would also need to agree that what this means is that the presence of the human observer impacts the outcome of the experiment.
Why would that be? Are subatomic particles or photons allergic to human beings? I dont think so. If they were, we would all be invisible because photons would stay away from us. And nobody would ever get an electric shock because electrons would avoid the human body. Do you think I am rambling? In a word, I am. But not from here.
If these particles or waves (take your pick) are not allergic to observer presence then there must be a rule of nature which leads to the phenomenon observed. Is this rule only with respect to the scenario described or can it be generalized? If we were to generalize it, then would it be an over-generalization to say that there are some aspects of nature which are not meant to be observed or measured? We cannot say that these phenomena dont occur because we cant observe them, because we can observe their manifestation. But we have to accept that we are not meant to observe the phenomenon itself. Question then is are there other such phenomena? There are phenomena which have been predicted but not yet observed, but this doesnt mean they would never be observed. There could, I believe, more such scenarios which would arise from developments in scientific thought. And this is where, I believe, we need to understand that not everything is meant to be observed or measures at the material level. That there are things which lend themselves more to thought than to observation, things study of the material universe may never be able to define.