MonoRealism Philosophy Site

Doubt and Certainty

Paradigm Shifts

A paradigm is a basic model of an aspect of reality. The philosopher Thomas Kuhn proposed that knowledge evolves by new paradigms replacing old ones, as evidence accumulates which makes the old ones unsustainable. How does this relate to the "truth" of theories proposed in the previous section?

Firstly, as with much philosophy, the theory of paradigm shifts is partly correct, but is not the rule. Most science proceeds by happy accumulation. Theories are modified but not invalidated at the root.

Secondly, a paradigm, though generally accepted as the best working hypothesis and most fruitful line of inquiry, is not necessarily regarded as "the truth". A theory may be the best explanation of the available facts, but if there are too few facts, or too little precision, or other possible explanations, then its truth remains uncertain. So a "shift" would not invalidate "truth".

Thirdly, new paradigms cannot keep coming forever. Eventually we reach the right one. A new paradigm, by definition, must be a better description of reality than the old one: as reality stays where it is, we thus get closer and closer to the truth. The phenomenon of paradigm shifts is a result of testing theories against a hard reality. A paradigm can only shift if it is wrong (not fully consistent with reality): and if it is wrong, it will shift, as reality eventually will prove inconsistent with it. A paradigm which is fundamentally right cannot be shifted, only refined, as reality cannot fundamentally contradict it. Proponents of paradigm shifts must agree that at least one paradigm is indeed true: the paradigm of paradigm shifts!

Finally, it is instructive to examine two famous paradigm shifts: Einstein's relativity versus Newton's laws, and the discovery of continental drift.

Newton vs Einstein

Newton developed laws of motion and gravitation which dominated physics for 200 years because of their explanatory and predictive power. Then slight discrepancies were discovered, which Einstein's theory of relativity explained perfectly. The end result was a paradigm shift from Newton's force of gravity in a flat, infinite universe to Einstein's curved space-time.

However, Newtonian physics remains a close approximation of the truth. Space is not flat, and gravity affects time: ideas inconceivable to Newton. Yet Newton's equations are so accurate in the absence of very strong gravity that they are still used: apples still fall, and the moon still orbits, by the equations of universal gravitation. Einsteinian physics is a deeper theory, with greater predictive power, from which Newton's laws are seen to be simplified approximations.

This is an example of an important type of paradigm shift: the new paradigm explains more things, and from it the old one can be derived as either a consequence, a special case, or an approximation. Such new truths do not invalidate old truths, but subsume them.

This case also illustrates the importance of precision. Discrepancies can be hidden in imprecise measurements: as technology improves and precision increases, the room for error shrinks and our confidence in our theories rises greatly. Pre-Newtonian celestial mechanics was quite inaccurate, but so were the measurements; Newtonian physics was close to the truth, but increasingly precise data showed up its limitations; now the confirmation of Einsteinian physics is very precise indeed.

Continental Drift

The continents used to be considered static, maybe rising and falling but certainly staying where they belong. Early this century, certain evidence led to the proposal that the continents move. In the absence of a credible mechanism, geologists rejected this theory.

Then evidence accumulated that the continents do move, carried on moving crustal plates. This evidence became overwhelming, and there is now no real doubt that continental drift is true. Of course, many details remain to be worked out.

This is an interesting case, as geologists were right to demand the onus of proof from the proponents of such a strange theory (they were wrong, however, to fail to integrate the evidence for it that did exist). However, there was no compelling evidence for the static earth either: this was just "common sense". Thus the prevailing paradigm, though the "best explanation" of the available evidence, never qualified by the rules of evidence as "true". What was true one day was not false the next: it was never true.

Three Modern Paradigms

The above is not merely knowledge after the fact. The status of a paradigm does not await hindsight, but is readily determined from the status of the evidence, at any time. To prove the point (and stick my neck out!), here is how I would judge three modern paradigms, based on my knowledge of the evidence.

  1. Quantum Mechanics: the extent and precision of confirmed predictions proves the basic theory (though "cutting edge" hypotheses are still up in the air, and the loonier interpretations are demonstrably false). Ultimately it will be derivable, as exact or approximate, from a deeper theory.
  2. Big Bang Theory of the origin of the universe: the best explanation of available facts, but not enough facts to prove it. May be confirmed and refined, or may suffer a complete paradigm shift.
  3. Evolution of living things: the fact of evolution and the important mechanisms of mutation and natural selection are true, but further as yet unknown mechanisms cannot be ruled out.

Paradigm Shifts and Reality

It is notable that paradigm shifts are only possible in an objective universe. No version of subjectivism, of the subjugation of reality to individual or collective whim, can account for such advances in knowledge.

What causes a paradigm shift? A generally accepted theory, usually with emotionally committed adherents, is forced to change by the pressure of new evidence. Whence such evidence? The facts of reality are inconsistent with the theory. In the memorable words of T.H. Huxley, it is:

"The great tragedy of science – the slaying of a beautiful theory by an ugly fact."

This is only possible if reality is unaffected by our beliefs, no matter how strong: reality can only be inconsistent with our cherished theories if it is independent of our consciousness. This is especially telling in the two cases analysed above, where the new paradigm is, by the "common sense" of collective humanity, bizarre nonsense.

Far from weakening the case that the universe is objective and therefore knowable, paradigm shifts prove it.

The Epistemology of Doubt

Empty doubt cannot influence our conclusions, but it does remain in the background as a reminder that we are not omniscient. The only valid conclusion from it is that one must always keep an open mind. An open mind is not one which believes nothing and exists in grey agnosticism, or which whines that it can't be sure: that is a mindless mind. An open mind is one which is always open to fresh evidence.

This is an inescapable consequence of the contextual nature of knowledge: if knowledge is the consistent integration of all known facts, then any new fact must be integrated with it. If a new fact is inconsistent with past knowledge, then this inconsistency must be handled: either the "fact" is wrong, or the previous explanation of the facts must be modified to incorporate it. It is as irrational to refuse to integrate new knowledge as it is to reject the integration of past knowledge.

The Three Laws of Doubt

From this discussion we can distil three laws of doubt for a rational mind (with apologies and change in order to Newton's laws of motion):

  1. First law: For every empty doubt, there is an equal and opposite empty doubt. These cancel each other out, forcing us to base our arguments and beliefs on an evaluation of evidence.
  2. Second law: A rational mind will continue in a belief until acted on by external reality. Rationality requires that you come to the best explanation of the facts available to you. Having done so, only new evidence can justifiably change your mind, and such new evidence must be integrated with the sum of your previous knowledge and opinions. This is a rational, open mind.
  3. Third law: The change in belief is proportional to the strength of new evidence, and inversely proportional to the strength of previously integrated evidence. That is, one may modify not at all, modify somewhat, or totally reject one's theories, depending on how the new evidence fits in with the old. The reasons are the same as for the Second Law. The mental equivalent of friction in this case is an irrational resistance to change: the desire to cling to a belief rather than to know reality. Sadly this is all too common!

The Ethics of Doubt

People, both individually and collectively, are not omniscient, and are capable of error in fact and logic. The implication for ethics is that the initiation of force between rational beings, to coerce thought or action in accordance with any belief, is morally evil. Each of us must act according to our understanding of reality, our values, and our judgements. To force another to act according to your judgements rather than his (where his actions are not demonstrably dangerous to others, i.e., themselves involving physical force), or to harm another simply because he won't accept your beliefs, is the most fundamental of crimes. By what right can a finite being force another against his judgement? You might be wrong. (Even if you did know everything, you would still have no such right, but that is another issue. To do it when there is real doubt, as with religion and politics, is unspeakable). If you cannot prove to a man's mind that he is wrong, then the rational and moral response is to let him be. Reality is the arbiter of truth and falsehood: it is against reality that our ideas succeed or fail, that we prosper or die.

Curiously, it is the very people who most preach doubt and uncertainty – mystics and subjectivists of all kinds – who most favour the use of force as the tool of ideology. Their ideology, the only one free from doubt! These preach statism in all its forms, proclaiming the right of governments to control individuals' actions and to seize their property according to the demands of the ruling ideology. This apparent contradiction is actually perfectly consistent with their philosophy: when you start from the premise that reality is what you want or what you vote, and not what it is, then the enslavement of men is your friend, and the rational judgement of free minds is your enemy. So then no matter what ideals you may start with, it is force and violence you will end with.

Thus we see the inevitable ethical consequence of evading reality: of bad metaphysics and bad epistemology. Human beings must live by reason and by understanding reality. If they refuse to do so themselves, then ultimately their only recourse is to enslave the men and women who do.

© 1993, 1996 Robin Craig: first published in TableAus.