Showing posts with label science. Show all posts
Showing posts with label science. Show all posts

Thursday, January 3, 2013

Teleology and the Limit of Science

I stumbled upon a Minute Physics video featuring Neil deGrasse Tyson discussing philosophy. I couldn't pass up this triumvirate of awesome things, so I gave it a watch.


After watching, I scrolled down to find that the comments section of this video, like any other where science intrudes on matters typically reserved for religion, is a veritable battlefield of choleric argument. But as I find occurring increasingly often, I discovered that I could not side with my fellow scientists (or, to say it perhaps more aptly given the inescapable subtext, my fellow atheists) in their rabidly empirical epistemologies. Certainly I share their conclusions, but I must also agree with the religious apologists that there exists a dogma of scientism in which the limit of our method is forgotten. I applaud Tyson for his argument, and I do this not simply because he plainly demonstrates the difficulty of the question, but because he does so with sober realization that conjecture, even empirically grounded, is not the same as fact.

Let us consider the epistemological basis for our method. Science entails a deliberate bias towards the null hypothesis—it carries the base assumption that, prior to empirical observation and statistical/logical/mathematical analysis of that observation, no knowledge exists except for one postulate: that, among any set of hypotheses, the possibility with the fewest positive assertions is the most likely. We can see this clearly in Tyson's thought as he systematically identifies issues which make particular postulates unlikely, and consequently defaults to the simplest postulate of all, the one with no positive assertions whatsoever, viz., that there simply is no purpose to the universe. This is, indeed, the idea most strongly favored by science.


But the humility of science must be preserved. There was a time that it saw no reason to believe that atoms contained discrete subparticles, and so it operated under the assumption that an atom was, as the concept's etymological root suggests, a truly indivisible billiard-ball-shaped item; this assumption was, as we now know, incorrect. It has been asserted by some on the basis of such corrections that science is merely a set of beliefs, that for all its pomp and surety it is really no different from religion. But this is an oversimplification. It would be more accurate to regard science as a pair of interdependent systems founded upon the same core principles: one of investigation, and one of speculation. Through the investigative system, science tests and re-tests its ideas with a statistical eye until it reaches assertions which tend to be so startlingly reliable that it is a struggle to call them anything other than objective fact. But the system of speculation employed by science is indeed simply speculation which happens to be systematic, and it is these speculations that we can accurately call beliefs; some might balk at this, but I would remind them again of the billiard ball atom and the multitude of other perfectly valid theories which ultimately proved wrong. We must keep our certainty within its statistical limits, and avoid ascribing to conjecture, even popular conjecture, any undue prestige by regarding it as fact.

Tyson is fully conscious of where science finds its limit, and he reminds us of this by both preceding and succeeding this discussion of science with admissions that he is uncertain in his belief. This gives us the proper way to regard Tyson's thesis: it is science, and it is mere belief, but this is neither a tautology nor a contradiction.

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Sunday, December 27, 2009

Time Travel

I will preface this by saying that someone else may have (in fact, probably has) thought of this before I did. The concept of a multiverse is certainly not mine, but if someone else has thought of its applications to time travel I assure you that I did so independently of them.

Assume that there is such a thing as the multiverse, the set of all possible states of the universe. Every time an event occurs with a random outcome, there exists for each possibility a universe in which that possibility is the one that occurred. Thus, when performing the famous double-slit experiment, there exists a universe in which the photon passes through the first slit, a universe in which the photon passes through the second slit, a universe in which the photon strikes the surface between the two slits, a universe in which the photon strikes a different spot on the surface between the two slits, a universe in which the photon fails to fire at all due to a power fluctuation, etc.

Now, let's consider two specific universes within this multiverse: universe Alpha and universe Beta. We will be looking at three points in time within each of these universes: moment 1, moment 2, and moment 3. Both of these universes contain an inventor named Joe. At moment 1 in universe Alpha (moment 1A), the Joe of universe Alpha (Joe-A) creates a time machine. At moment 2A, there is only one Joe present and he is still alive; this may seem inconsequential now, but its relevance will become apparent. At moment 3A, Joe-A uses the time machine to travel back to moment 2 and meet the Joe that he finds there. According to a common interpretation of time travel, Joe-A meets himself at moment 2A. However, we have already seen that there is only one Joe at moment 2A. Either there is one Joe at moment 2A, or there are two; both cannot be true. Because we already know from previous experience as absolute fact that there was a only one Joe at moment 2A, it must be true that we are not looking at moment 2A; we are now looking at moment 2B, and Joe-A has met Joe-B.

Now suppose that Joe-A kills Joe-B at moment 2B. When moment 3B arrives, the deceased Joe-B is no longer able to use his time machine to go back and kill himself. Had this scenario been played out on a single timeline in a single universe, causality would be violated by a classic temporal paradox. However, the existence of the multiverse means that both possibilities (that Joe is alive and that Joe is dead) can exist simultaneously.

In the course of looking up a few terms while typing this, I came across this, which shows that this is not, in fact, an original idea. Alas. I'll post it anyway, because it's still interesting and because I spent so much time on it.