Sunday, April 13, 2014

Science, models and paradigms

Science as a field is the empirical discovery of how things work. Normally, science works through models. In logical positivism, scientific theories work by means of verification. In this model, one has a model, a theorem, or a hypothesis. One tests the model through doing experiments. Depending on the data one receives from the (empirical) experiments, which ideally should be double-blind (especially in clinical trials) and repeated as many times (to minimize variation in the results as much as possible), the results either prove or disprove the model/ theory/ hypothesis. This is what most scientists think they are doing: they are validating a model that they propose. They have a null hypothesis (H0), and an alternate hypothesis (H1), which could be simply the negation of H0. In the ideal experiment (which seldom exists), the scientists can run enough tests to generate more than 30 results, so that he can plot the results on a normal distribution curve to test the null hypothesis. In science, there are no bad results. Even negative results say something, although whether that is helpful or not for his research project is of course a question the individual scientist has to think over.

In the early 20th century, Karl Popper proposed an alternate way of how science is thought to work. Popper recognized, quite rightly, that the verificationist theory of scientific methodology is logically fallacious. Holding to that view of how science works mean that every scientist has been committing the logical fallacy of affirming the consequent (If p, then q, q; therefore p). Now, it is certainly possible for science to discover true things despite having a flawed view of scientific methodology. However, it also means that it is possible to think that one has proven a model when that model is actually false. After all, if two models predict the exact same empirical result, how can one choose between the two unless one can come up with another experiment to which the two models will predict different results. While this sounds easy to do, such testing is harder in practice than it is said. For example, a key component of the mainstream Big Bang theory, ΛCDM, is the (generalized) Copernican principle, which states that the universe has no actual center. [The "explosion" is not a explosion of mass into a 3D space. Rather, it is the explosion of space and matter in a 4D hyperspace. To use a balloon analogy, the surface of the balloon is the 3D universe we are in, while the "air" inside the balloon signifies "hyperspace," and as such both 3D space and time "ballooned" into being.] According to observable data, most of the universe is red-shifted to us, implying that those objects are moving away from us (to be clear, it is thought that it is the space that is moving or expanding, not the object that is actually accelerating away from us). Now, if everything we observe is moving away from us, then it could imply that we observers on earth are at the center of this movement. That is where the Copernican principle comes in. If all space is like the surface of a balloon without a center, then the mere observation of almost everything being red-shifted away from us means nothing. The Copernican principle states that anywhere in the universe, any observer will see a general red-shift of most stellar and extra-galactic objects moving away from us.

The question before us is: just how are we supposed to test the Copernican Principle? Yes, Geocentrism is out. But how does one prove or disprove galactocentrism? The issue of quantized red-shifts for example seems to suggest some form of galacto-centrism.

The key point I want to drive at is that testing between two competing models is not as easy as it sounds. But I still haven't discussed Popper's alternate proposal. Popper's proposal is to replace a theory of verification to one of falsification. Instead of having science prove something, the purpose of experiments is to disprove something. Science according to Popper disproves models, not proves models. By disproving an alternative, the scientist can show that his model is more likely, or even most likely.

It is safe to say that most scientists have not progressed to the Popperian stage. It is not sufficient to use Popper's vocabulary of falsification, but to also understand that Popper's philosophy of science places a significant limit to the ability of science to decipher truth. If Popper is right, then science can only discover workable data that are likely true, not "truth."

The last theory to be looked is that of Thomas S. Kuhn. Kuhn's idea of paradigms and paradigm shifts has unfortunately sometimes been misunderstood by large swaths of the public, most notably C. John Collin in his book Science and Faith: Friends or Foes. Kuhn's theory, at least the initial part, is elegant yet simple. Scientists come to their inquiries with a certain frame of mind; i.e. they are not tabula rasa. A paradigm is a general worldview or mindset that informs and influences scientists, and that is conditioned by the prevailing scientific culture (or "academic culture" pre-Enlightenment) among other intellectual and social factors. The frame of mind influences scientific research, directing the questions to be asked and the burden of proof required, as well as which models are seen to be more likely. Paradigm shifts occur when sufficient outliers and unresolved problems with the current models are present to induce a shift to another paradigm. Note here that paradigms are NOT models. They can rather be termed a "meta-model" if you wish. And while the earlier Kuhn speak of times of crisis during paradigm shifts, the later Kuhn admits that the shifts might not be some earth-shattering transition with a clear temporal demarcation.

The implication Kuhn's theory has on science is huge, which is probably why most scientists aren't too keen on what he has to say. He is almost, as it were, the "post-modern" philosopher of science. But it is very likely that Kuhn's philosophy of science is in fact true. The climate science scandal is one such clear example whereby those who deny Global Climate Change (at least in its current apocalyptic form) are censored because of a prevailing paradigm for Global Climate Change. More pertinent to our discussion here, and back to our example, why is the Copernican Principle in the idea of a center-less universe accepted when there is, at least currently, no way to prove it? Or let's take another example going back to biology, why is abiogenesis affirmed even though every experiment done has failed to prove it? The Miley-Urey experiment after all does not count since (absent the discussion of the exact constitution of the primeval atmosphere and "soup"), a racemic mixture of amino acids is far from evidence for even the natural constitution of the basic blocks of life (which requires D-sugars, L-Amino Acids, and D-nucleotides for starters).

There are a lot of problems with the naturalistic evolutionary narrative of the universe, but we are not even at the point of discussing them. The issue is that the evolutionary narrative itself as a paradigm (a "meta-model") is to a certain extent not falsifiable. That is Kuhn's contribution to our discussion and the philosophy of science. Because of a reigning paradigm, science itself is not neutral in the way it is portrayed by scientists. A telling example is in the evolutionary metanarrative, both the presence and the absence of transitional fossils are considered proofs for evolution. If one accepts the former, one holds to Gradualism. If one accepts the latter, one holds to Punctuated Equilibrium. Thus, at least on the subject of transitional fossils, evolution is not falsifiable. Such manner of rendering the meta-theory unfalsifiable is not limited just to transitional fossils, but is pervasive. Note the controversy or rather non-controversy over the Big Bang model, even when the expected amount of dark matter and dark energy were not found as expected by their models. Instead of jettisoning the Big Bang [meta-] model, scientists went back and proposed modified models to try to account for the observations, even while keeping the Big Band paradigm. Stories like this show that the paradigm is not testable and not falsifiable. Thus, at the back of scientific models lies the reigning paradigm, which by its nature is elastic enough such that only extreme stress on the paradigm would cause a transition to another.

Putting the various philosophies of science together, we can see that many scientists think of their work like logical positivists. Most of them hopefully work like Popperians, while in actual fact the scientific enterprise work in Kuhnian paradigms and paradigm shifts. Christians ought to recognize this, because otherwise we will always be on the defensive against the supposed claims of science.

[to be continued]

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