Thursday, May 17, 2018

Scientific Revolutions #3

The histories of science portrayed by Thomas Kuhn and Karl Popper -- according to their critics -- diverge from actual history. Parsons' counter-story follows.

"The history of science is not one of steady cumulative progress, but neither is it a succession of mutually exclusive paradigms where each new theory wipes the slate clean and starts all over again. If we regard all past theories as totally false, then the pessimistic metainduction probably should make us doubt our present theories, however empirically successful they are. But the history of science is not like the famous Peter Arno cartoon from the New Yorker: A test flight has just ended in a horrendous crash. The aircraft designer turns his back on the ensuing chaos, [and blithely says], "Well, back to the old drawing board." Science does not have to go back to the old drawing board with every superseded theory. Rather, when we look at the history of any field of science, a few theories will stand out as major breakthroughs. Once these breakthroughs occur, they are retained, in one form or another, through all subsequent theory changes, even through major conceptual revolutions. For instance, the mathematician and physicist James Clerk Maxwell (1831-1879) formulated a small set of simple equations that explained all the diverse phenomena of electricity and magnetism. He concluded that electricity and magnetism were different aspects of the same force, electromagnetism, and that light is actually a form of electromagnetic radiation. Maxwell's Treatise on Electricity and Magnetism was published in 1873, well before the two major revolutions in twentieth-century physics, relativity and quantum mechanics.
     The revolutions of twentieth-century physics overthrew some of Maxwell's ideas. For instance, he thought that since light was a wave, it had to be carried by some medium, the "luminiferous ether," an idea rejected by subsequent theory. However, light is still regarded as electromagnetic radiation, and Maxwell's equations, in modified form, are still regarded as valid for a given range of electrical and magnetic phenomena. Likewise, Newton's famous law of universal gravitation is retained in physics as correctly applying to things not moving too fast and to gravitational forces that are not too strong. So, many of Maxwell's ideas, like Newton's, have survived the enormous conceptual upheavals of the relativity and quantum revolutions, revolutions that overthrew so many of the ideas of "classical" physics. Within limited contexts, Maxwell's and Newton's theories are just as valid as they ever were. Other breakthrough theories have shown similar staying power in other fields of science" (p. 183-4).


Monday, May 14, 2018

Scientific Revolutions #2

In chapter 3 of It Started With Copernicus Parsons takes a "walk on the wild side", about those who criticize the idea that science is a wholly rational pursuit of truth. The "wild side" refers to social constructivism and postmodernism.

He concludes that while science is far from perfect -- like any human enterprise -- there is still something left of science idealized. There is a physical world "out there," and we can know something about it. We can say that some things really just are so, and not mere artifacts of our percepts, concepts, and categories. Further, our observations of the physical world can be used to rigorously evaluate our theories, so that our theoretical beliefs are shaped and constrained by nature, and not merely like in politics, rhetorical manipulation, or ideology. Disinterested knowledge is really possible, and is, in fact, achieved far more often than cynics suppose.

Nevertheless, the critics have succeeded in disposing of what might be called the "passive spectator" stereotype of knowledge. As that story goes, once people started looking at nature rather than old books, scientific knowledge flowed into open scientific minds like water pouring into an empty bucket.

Scientific discovery requires active engagement, not just passive seeing. Galileo didn't just look through his telescope and report what he saw. He interpreted, theorized, speculated, measured, analyzed, and argued. Darwin did not go to the Galapagos Islands and suddenly awaken to the truth of evolution in a flash of obvious insight. His notebooks reveal a complex process of questioning, argument, and counterargument, with tentative conclusions drawn and then rejected or refined. Scientists do not just absorb a picture of the world; they create a picture and then do their best to see how accurate it is.

Friday, May 11, 2018

Scientific Revolutions #1

I intended to borrow Thomas Kuhn's The Structure of Scientific Revolutions from the library to read it again after several years. Then I saw It Started With Copernicus by Keith Parsons on the shelf and borrowed it instead.

Here is another article about Kuhn and his book. Published in 1962, it attracted much attention with its ideas of paradigm, normal science, and incommensurability, with different paradigms being incommensurable. Parsons states three kinds of incommensurability in Kuhn's book (Chapter 2). They are about standards, values, and meaning (or semantics).

Standards pertains to what constitutes good science. Parsons' first example is why versus how as it pertained to Newton's position on gravity. "Must a theory of motion explain the cause of the attractive motion between particles of matter, or may it simply note the existence of such forces? Newton's dynamics was widely rejected because, unlike both Aristotle's and Descartes's theories, it implied the latter answer to the question" (p. 59). Another example is from paleontology.

Competing paradigms may disagree in basic values. Each theory, even in terms of its own standards, will have its own successes and failures. Which theory should we value more, the successes of one or the successes of the other? Which is the greater liability, the failures of one theory or its rival? Should we regard the successes of a theory as outweighing its failures?

Competing paradigms may use different meanings for the same term, e.g., mass, time, or gravity. While these term may refer to the same phenomena in Newton' and Einstein's physical theories, they are not understood the same.

As the above links show, Kuhn's ideas received plenty of criticism. Parsons is a critic, too, but gives Kuhn some credit.

Monday, April 23, 2018

The Is-Ought Problem #2

I wrote about the is/ought problem almost two years ago here. Therein I said I had decided that an "ought" statement cannot be deduced from an "is" statement – which agrees with David Hume -- but an "ought" statement can be based on an "is" statement.

Hume’s famous statement of it is included here. He denied deducing an “ought” from an “is.” On the other hand, he indirectly denied any connection between the two using reason. This is likely why some call it Hume's guillotine.

I recently saw a video by Yaron Brook of the Ayn Rand Institute in which he talks about the is-ought problem. Around 2:00 he talks about generating an “ought” from an “is” and bridging the is-ought gap. I believe these are other ways of saying an "ought" statement can be based on an "is" statement, but they are not by deduction

I also saw this article about Ayn Rand and the is-ought problem. I liked his following syllogisms about is/ought:

“The sole difficulty arises over the derivability of values from facts. 

The following syllogism does not violate Hume's Law:

     One ought not to murder human beings.
     Socrates is a human being.
     Therefore, one ought not to murder Socrates.

On the other hand, the syllogism below does violate Hume's Law:

     Human beings have a right to life.
     Socrates is a human being.
     Therefore, one ought not to murder Socrates.

The second syllogism is defective, for it requires for its conclusion the premise that one ought to respect the rights of others. Add that assumption, and one has a valid syllogism which integrates facts and values” (84-5).

Sunday, April 15, 2018

Personal Knowledge #3

Two conflicting systems of thought are separated by a logical gap. "Formal operations relying on one framework of interpretation cannot demonstrate a proposition to persons who rely on another framework.  Its advocates may not succeed in getting a hearing from them, since they must first teach them a new language, and no one can learn a new language unless he first trusts that it means something. A hostile audience in fact may in fact deliberately refuse to entertain novel conceptions ... because its members fear that once they have accepted this new framework they will be lead to conclusions which they -- rightly or wrongly -- abhor. Proponents of a new system can convince their audience only by first winning their intellectual sympathy for a doctrine they have not yet grasped. Those who listen sympathetically will discover for themselves what they would otherwise have never understood. Such an acceptance is a heuristic process, a self-modifying act, and to this extent a conversion. It produces disciples forming a school, the members of which are separated for the time being a logical gap from those outside it. They think differently, speak a different language, live in a different world, and at least one of the two schools is excluded to this extent for the time being (whether rightly or wrongly) from the community of science" (Personal Knowledge 151).

The above has some resemblance to the idea of different paradigms posited by Thomas Kuhn in his book The Structure of Scientific Revolutions (link). Polanyi's book was published three years before Kuhn's. Kuhn's book refers to Polanyi or Personal Knowledge only about tacit knowledge, which is acquired through practice but not explicitly articulated. However, it seems Kuhn made the gap between the adherents of different schools of thought wider.

Polanyi titled his book Personal Knowledge in contrast to the widely held idea that true knowledge is deemed impersonal and objective. Polanyi holds that tacit knowledge is a significant part of personal knowledge, yet not subjective.

Tuesday, April 3, 2018

Personal Knowledge #2

The value of a theory may be judged on its fruitfulness. Michael Polanyi wrote the following about truth and fruitfulness.

"You cannot define the indeterminate veridical powers of truth in terms of fruitfulness, unless 'fruitful' is itself qualified in terms of the definiendum. The Ptolmaic system was a fruitful source of error for one thousand years; astrology has been a fruitful source of income to astrologers for two thousand five hundred years; Marxism is a fruitful source of power for the rulers of one third of mankind. When we say that Copernicanism was fruitful, we mean that it was a fruitful source of truth, and we cannot distinguish its kind of fruitfulness from that of the Ptolmaic system, or of astrology, or Marxism, except by such a qualification. To use the word fruitful in this sense, without acknowledging it, is a deceptive substitution, a pseudo-substitution, a Laplacean slight of hand.
     But even when fruitfulness is taken to mean the capacity of leading to new truths, it is an insufficient characterization of truth. Copernicanism could have well been a source of truth ... even if it had been false. But the Copernican system did not anticipate the discoveries of Kepler and Newton accidentally: it led to them because it was true " (p. 147).

"The mark of true discovery is not its fruitfulness but the intimation of its fruitfulness" (p. 148)

I guess that he meant the following by 'intimation': the action of making something known, especially in an indirect way.



Thursday, March 29, 2018

The Great Math Mystery

Last night we watched The Great Math Mystery, a NOVA episode on PBS television. It was excellent and I recommend it. It can be watched on-line here at least temporarily. There is a full transcript, too. The mystery is:  Is math invented by humans, or is it the language of the universe? Reasons are given for both -- some math is invented and some is discovered.  I believe the best answer came near the end. Math concepts such as numbers are abstracted by humans, but then they and their relationships are found to apply beyond their origin and lead to further discoveries.

The topics include the Fibonacci sequence, the number pi, Galileo's mathematics of falling bodies, Maxwell's equations, Marconi's discovery of radio telegraphy, the quantitative intelligence of lemurs, and the difference between pure math and applied math. Regarding the last, pure math is exact and imaginative but becomes much more useful via approximating with short-cuts such as done by engineers.