156 cosmos
but realized that this was a point on which he and Hoyle differed. He said to
Hoyle: “I think of the possibilities; you are the one who speculates.”
Whereupon Hoyle replied: “I do not set as a requirement that the answers be
right.” This reminds us of the famous words of Whitehead: “[It] is more im-
portant that a proposition be interesting than that it be true.”^39 Here the remark
of J. D. North is relevant: “The individual theory of cosmology is neither true
nor false; like any other scientific theory, it is merely an instrument of what
passes for our understanding.”^40
We should be reluctant today to say of any scientific theory that it is true.
In the eighteenth century this is precisely what was said of Newton’s theory.
D’Alembert wrote in 1757: “The true system of the world has been recognized,
developed and perfected.”^41 In the nineteenth century, confidence in Newton’s
theories began to wane, and in 1900, quantum theory, and in 1905–16, special
and general relativity brought a new era in physics. When Einstein predicted
that starlight is bent when it moves past a massive body in space, Arthur
Eddington led an expedition designed to test the prediction. After much check-
ing of the data, he went on record as saying that his findings “prove” general
relativity. When this was announced to Einstein, his response was: “The truth
of a theory is in your mind, not in your eyes.” But when it was brought to the
attention of the Royal Society, its president, J. J. Thomson, remarked: “It [gen-
eral relativity] is the greatest discovery since Newton enunciated his princi-
ples.”^42 Eddington’s expedition had set out to “confirm” or “verify” Einstein’s
theory. Now that it was “confirmed,” what was to said of the new physical
theories, that they are right and the older theories wrong? The philosophy of
science arose in this century to respond to this question.
Michael Ovenden, an astronomer friend, expressed a belief about the older
physics that shows how far some physicists have come on the truth question
in light of the new situation in physics:^43
The [laws of motion] could in no sense be proven wrong; they are
wholly tautologous, in that, if you measure a force by the rate of
change of momentum, then whenever there is a change of momen-
tum you will automatically say a force is acting. Of course, when
you go from this to applying it to our experience, then the question
you have to ask is, does that particular way of looking at things
make the world look simple? If so, it is a good theory. If not, then it
is not a good theory. And of course, eminently so does Newton’s
theory do this.
Karl Popper, the eminent philosopher of science, was more of a realist,
though expressing caution in what we say about prevailing theories. He pro-
posed that we say that a prevailing scientific theory is one that is “corroborated”
rather than “verified,” but then threw caution to the wind by claiming that
there is a growth of scientific knowledge in that the successive development