about Objectivity of physical Entities and Laws
In 1937 was held an interesting debate about realism in disguise of a sensualism-rationalism-discussion. It's no accident that such a debate arised from physics, because physics has to ask about the objectivity and reality of their "things" and object-subjects.
Herbert Dingle began to outline two points of view to this issue. He distinguished the older "Aristotelianism" and the new science since Galilei. The "Aristotelianism" is "the doctrine that nature is the visible working-out of general principles known to the human mind apart from sense perception" (Dingle (a), p. 784) and in science we proceed on the assumption "that the first step in the study of the Nature should be sense observation, no general principles being admitted which are not derived by induction therefrom" (Dingle (a), p. 784).
The question is:
Dingle continued with the fact that science until now preferred the way of Galileo. But now - he said - we can see a "revival of Aristotelianism", which comes "by metaphysics out of mathematics" (Dingle (a), p. 784) in the context of the theory of relativity. L.N.G. Filon described the new Aristotelianism in this way:
"… some man of science appear to think that they can solve the whole problem of Nature by some all-inclusive mathematical intuition. What they are really doing is not to explain Nature, but to explore the possibilities of the human mind." (Filon, p. 1006)
The theory of relativity changed our world-view, our view of our universe. It is founded in some assumptions: the assumption that the universe is homogeneous, that it is isotropic and so on. These assumptions are chosen to bring the universe within the scope of our mathematical attainments. And we get laws, and these laws "are universal, eternal, established on the rock of divine mathematics" (Dingle (a), p. 785). This view seduces someone to think "there is nothing in the whole system of laws of physics that cannot be deduced unambiguously from epistemological considerations" (Eddington, cit. in Dingle (a), p. 785 ). Also Milne and Dirac are criticized as "victims of the great "Universe" mania" (Dingle (a) , p. 786). Milne only works in the field of equations and isn't interested in the concrete circumstances. The solution of a problem ends in forming the equation; no concrete conditions are examined. Dingle calls this procedure "cosmythology" (Dingle (a), p. 786).
Dingles view is another view: He emphasizes that "the relation of relativity to the universe is in principle precisely the same as that of Newtonian mechanics" (Dingle (a), p. 785):
"Newtonian mechanics could not state the number of planets in the solar system or the distribution of masses in the universe, but if these things were found by observation, it could tell how the bodies would interact" (Dingle (a), p. 785).
Than in the Supplement of Nature a detailed discussion took place.
At first E.A. Milne made clear that the assumption that the universe is homogeneous is not only an ordinary physical hypothesis (Milne, p. 997). And he noticed that the role of abstract theorems in physics is not only a problem of general relativity. And the question of homogeneity is independend from the theory of general relativity. Milne defended the usefulness of the procedure to take hypothesises (i.e. geometrical) without empirical support , to get regularities "which play the part to the very laws of Nature" (Milne, p. 998) and than - more or less astonished - to see that they "are observed to hold good." He emphasised: "The theorems exist in their own right" (Milne, p. 998).
| "Should we deduce particular conclusions from a priori general principles or derive general principles from observations?" (Dingle (a), p. 784) or "But the question to us now is whether the foundation of science shall be observation or invention?" (Dingle (a), p. 786).
There is a difference of a geometrical axiom or theorem and a law of nature, the difference of mathematics and physics . The role of observation is the difference. But usually observation is not the first task. Maybe it helps to discover theorems empirically, but mostly it helps to verify the relevance of the theorems, "to identify in Nature objects corresponding to, or approximately realizing, the entities mentioned in the axioms" (Milne, p. 998).
Milne explained that geometry itself has two aspects: the aspect of pure deductivity (such as in the Greek geometry) and the aspect of empirical evidence (such as in the Egyptian geometry).
In physics the pure empirical aspect would let the knowledge approximately, because induction is never complete - and the pure axiomatic aspect would be mathematics only.
"The relevance of the theorems to Nature would require to be established by observation, but these theorems or laws of Nature would hold good in their own right…" (Milne, p. 998)
The admission of Milne that the systems "may or not may have their counterparts in the external world" confirmes Dingle's reproach: "He does not want to find out the truth about Nature; he wants to make a theory" (Dinlge (b), p. 1011) .
Arthur Eddington used the paper of Dingle to explain his own view. He differed between the knowledge about an "objective universe" (Eddington, p. 1000), about which we can't have any a priori knowledge, and the knowledge (i.e. of the mass-ratio), which "is not knowledge of an objective universe" . He inferred:
"The general laws of Nature (embodied in the fundamental equations of mathematical physics), including the universal constants associated with them, do not express knowledge of an objective universe." (Eddington, p. 1000)
Only in particular systems and events, which can be observed, he could find any objective aspect. In this sense Eddington turns out to be a nominalist and anti-inductivist. A Law of nature is "not merely an empirical regularity".
"Observations, besides revealing laws of Nature, supplies details of particular systems and events. It is in these particulars that the objective element in our knowledge resides; there is no objective element in the general laws." (Eddington, S. 1000)
But there is not only a gap between the objective universe and the non-objective theoretical universe. At first we anticipate the information in an Aristotelian way, and than we do an a posteriori Galilean induction to obtain the information.
Paul Dirac stressed that "the development of science requires a proper balance to be maintained between the method of building up from observations and the method of deducing by pure reasoning from speculative assumptions" (Dirac, p. 1001). Especially the constants of Nature are provided by observation.
More precisely W.H. McCrea explained, how mathematical physics works in order to reduce the number of its hypotheses (McCrea, p. 19002) and Haldane added that also very abstract hypotheses usually have a foundation in experiences. But of one would reject all mathematical constructions, one would reject the Copernician theory as "cosmythology" too, as G.J. Whitrow outlined (Whitrow, p. 1008). And Kepler's work based on his belief in mathematical harmonies in Nature, not on pure induction.
Eddington, Arthur: Physical Science and Philosophy. Nature. Supplement 139 (1937), S. 1000-1001.
Dingle, Herbert (a): Modern Aristotelianism. Nature 139 (1937) S. 784-786.
Dingle, Herbert (b): Deductive and Inductive Methods in Science. Nature. Supplement 139 (1937), S. 1011-1012.
Dirac, Paul: Contribution to the debate "Physical Science and Philosophy". Nature. Supplement 139 (1937), S. 1001-1002.
Filon, L.N.G.: Contribution to the debate "Physical Science and Philosophy". Nature. Supplement 139 (1937), S. 1006.
Haldane, J.B.S.: Contribution to the debate "Physical Science and Philosophy". Nature. Supplement 139 (1937), S. 1003-1004.
Hicks, Dawes G.: Contribution to the debate "Physical Science and Philosophy". Nature. Supplement 139 (1937), S. 1009-1010.
McCrea, W.,H.: Contribution to the debate "Physical Science and Philosophy". Nature. Supplement 139 (1937), S. 1002-1003.
McEntegart, W.: Contribution to the debate "Physical Science and Philosophy". Nature. Supplement 139 (1937), S. 1009.
Milne, E.A.: On the Origin of Laws of Nature. Nature. Supplement 139 (1937), S. 997-999.
Whitrow, G.J.: Contribution to the debate "Physical Science and Philosophy". Nature. Supplement 139 (1937), S. 1008-1009.
- This page is a part of the web-project "Annettes
2003 - http://www.thur.de/philo/project/nature.htm