Friday, December 26, 2003

How Modern Science Came to Eliminate the Idea of Purpose

I’ve been reading Jacques Barzun’s amazing From Dawn to Decadence: 500 Years of Western Cultural Life, 1500 to the Present (HarperCollins, 2000). Today I came across the following comments on the advent of modern science:

When we speak of 17C science and scientists we are committing an anachronism. At that time the word science had not been narrowed down to one kind of knowledge; it meant whatever was known. . . . Those who spent much of their time in investigating nature were called natural philosophers. . . .

The road to the present was hard and long because the old systems were good. They had consistency and completeness; only at a few points did contrary facts or gaps in explanation threaten their validity. One such fact was the odd behavior of the planets, especially Mars, which at times went backward instead of forward. Another ill-explained phenomenon was that of horizontal motion: what keeps an arrow flying so far and no farther? Does the push of the bowstring put something into the arrow? Or, as some thought, does the air get displaced around the head and keep propelling it? Lastly, why do these forces give out?
Barzun does a great job setting up the problem more thoroughly. But here’s what particularly caught my attention.

For centuries, movement was studied by thinking of the arrow in flight or the cart drawn by a horse—it was push or pull by an unknown force. But what about falling bodies? After Galileo and Newton, by abstraction, motion no longer raised images of movement; it was defined geometrically as change from place to place, its rule being that it will continue forever until something stops it:—an obstacle or the friction of the air. Similarly, an object at rest stays put until a force is applied to it. The two statements make up the law of inertia. It is a law not because objects “obey” it—that again is a skewed interpretation; the law is only a statement of regularity in behavior. . . .

The common-sense look of things is not to be trusted; it is too variable. The human aspect of the world and human use of objects must be ignored by the student of nature. In this purging of variety the importance of words is considerable: it helps to keep the geometrical idea in mind. Thus mass is better than weight, which suggests a burden pulling at one‘s arms. Force also seems to imply our own exertion, and energy does not—or not so much. The abstract word gravitation conceals “heavy” very nicely. Again, references to spirit or principle to account for what happens are too vague and suggest unseen “powers.” . . . To sum up, any “anthropomorphic”—manlike—view of things is wrong in principle and will mislead. Especially wrong is the belief that anything in nature fulfills a purpose. Aristotle’s physics relied on a doctrine of ends, of final purposes and meanings. The reverse assumption yields the truth of science, not movement toward goals but purposeless push or pull that need not end.

It goes without saying that the cultural consequences, the effect on human lives, of this shift in outlook have been profound. To begin with, as success in “natural philosophy” became evident in one realm after another, scientists, as we now call them, came to be regarded as “those who really know.” This in turn meant that reality was split—scientific fact and human experience, no longer one and often contradictory. If the one was real, the other must be illusion.

—Barzun, pp. 191-195

I had never thought of these things before: how our scientific philosophical assumptions affect our view of purpose (or purposelessness) . . . and how in my own life, it is true: I have been taught, mostly, to consider scientists as "those who really know": "Science is true knowledge; everything else is conjecture."

But is that true? Is it true, 1) that science is always true knowledge? And, 2) that everything else is "mere" conjecture?

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