19 April 2009

Response to a Humian Argument

Just pointing out this post at Neurologica. I got into a debate on this very theme a few weeks back at philosophy club. The short version is that science itself does not have a solely rational basis. As Hume noted, scientific inference requires assuming some form of uniformity in nature, generally phrased as "the future will resemble the past."

I need to read Novella's post again more closely, but I'm not sure that he's found a way out of the assumption. Yes, science is a method, but it seems to me that the very method requires the assumption that "the future will resemble the past." Otherwise, what purpose would testing anything serve? What worked on Tuesday might not work on Wednesday (or we might skip over Wednesday and wind up at Friday). Yes, the method is "self-correcting," but there would be nothing to "correct" without some form of uniformity.

As science has produced reliable results in the past, and continues to do so today, it may seem that we could make a probability argument, that all of those "hits" are so unlikely to be due to chance that we can reject that hypothesis. For the present. But as soon as we try to extend that into the future, we run into the uniformity problem again. An a priori assumption is required, and I still don't see a genuinely grounded basis for that assumption. Perhaps I'll find that there is one next fall, when I take Philosophy of Science, but for the moment I'm unconvinced.

Now, I don't think this invalidates science in any way, shape or form. I just think that it needs to be recognized and acknowledged. We do have evidence of uniformity throughout most of the past, so it seems probable that uniformity will continue for some time into the future. It's just not guaranteed. To my mind, the most important thing people should understand about science is that no theory, no hypothesis, no conclusion is ever held as sacrosanct. New evidence always has a chance of dislodging it. It seems somehow appropriate that if the uniformity principle were ever broken, science would likely be overturned in its turn.

Anyway, the post at Neurologica is certainly worth reading. And perhaps someone can tell me what I've missed in Novella's argument...

Vaguely related aside: I haven't encountered anyone trying to use Hume to argue for anything "New Age" in opposition to science, but there's an immediate problem if they do. "New Age" methodology also has a history, and also presumes that if something worked in the past, it will work in the future (so long as you believe in it in just the right way, and do it in the 14th arcminute of the third full moon of the 1000th year since.........). So such an argument is just as damaging to their own methodology, whatever it may be. Even invoking randomness, a la Tarot Cards or Yi Jing, presumes that the same random results point to the same "advice."

My best guess is that someone using this in that manner would be arguing for something on the order of revelation or intuition. Hmmm, no, still doesn't work. Why do they trust revelation? Because it's been correct in the past! (FYI: Hume is my favorite modern philosopher to read. Very Dickensian in his writing style.)


John said...

Yes, the scientific method has one basic assumption: The universe behaves rationally.

This assumption is based on hundreds, or thousands, of years of observation. It's held up so far.

Qalmlea said...

Yeah, that part I agree with. There just doesn't seem to be a genuinely rational reason to think that the universe behaves rationally. At some level, there is always going to be an assumption.

Maybe if we figure out time better, we'd have an idea why it behaves rationally. Maybe. Or maybe that would just shove the assumption back another level.

Rene Benthien said...

Isn't is rational to take into account the empirical evidence that suggests the universe is rational? Even if there is no philosophical proof.

In any case rationally speaking, doesn't this make science valid as THE method of understanding nature as opposed to pseudoscience and religion?

Qalmlea said...

I think we're always left with an irrational leap into the future. A justified irrational leap, or maybe an unavoidable irrational leap, but a leap nonetheless.

I do think the best argument for that leap comes from evolution. We've evolved to expect the world to behave rationally. If that were not at least a reasonable approximation of the world, we would not have evolved in such a way. It's also debatable whether evolution of any sort of life would be possible in a world with little predictability.

The key to Hume's line of thought (as I understand it) is that we cannot use past data to deduce that the future will resemble the past. We can only infer that it will. At any moment, we might turn out to be mistaken.

Anonymous said...

Yes, this is one of the assumptions we must make to use the scientific method, or to live our daily life.

Anyone who argues against science on this basis is ultimately a hypocrite. (not accusing you of this, Qamlea)

Questions for a hypothetical science-denier: Why do you stir sugar into your coffee every day? How do you know it will make it taste sweeter today as it did yesterday? If your child develops a dangerous reaction after every time he or she eats shrimp, will you stop feeding her shrimp, or just keep doing it?

Science is just a formalization of the technique we ALL use every day. The technique is just common sense. It's results and implications are not.