2. Three short examples of the need for logical revision

Here is a basic commonsense question. Do bodies anywhere travel in straight lines? Everyone knows that when a ball or any other object is thrown, it follows a curved trajectory. Even balls on a billiard table and pucks on ice would be seen to travel in curves if the surfaces on which they travel were long enough. (For a billiard-table to be level both here and over the horizon it would have to be curved to fit the earth's curved surface at every stage along its length.)

Why, then, in physical science, has it been assumed, for three centuries, that the underlying natural state of motion for a freely moving body is in a straight line? The answer contemporary science gives is that all bodies would travel in that way if it were not for the presence of hidden forces, like those of gravity, electrostatics, magnetism and so on. These, we are told, are present everywhere, preventing everything from planets, stars and galaxies to atoms, electrons, protons and nuclear particles, from travelling in straight lines in the way Newton's First Law of Motion dictates. So the consequence of this assumption of naturally straight-line motion is to produce a theoretical proliferation of invisible in vacuo forces being responsible for the fact that nowhere do bodies move in the way Newton assumed they should.

Nor is that that the only assault that contemporary physics makes on commonsense. There are many others. For instance, who could accept the statement: 'A man is human, so all humans are men.' (The female section of humans on this planet might have something to say about that!) Yet despite the obvious fallacy in this form of reasoning, there are scientists who, from the fact that the light from any receding body is Doppler-shifted towards the red, on seeing the light from distant galaxies shifted towards the red, throw commonsense to the winds and interpret it as an incontrovertible 'fact of observation' that those galaxies are receding from us, and from one another, in a primeval explosion that created the whole universe of space, time and matter from something less than the size of a pea, some fifteen billion years ago!

Here is another example, from many others that might have been chosen. Textbooks and encyclopaedias of physics describe the quantum of light-energy as a 'particle' of light, called a 'photon', travelling at the finite and constant speed c. However, the received Theory of Relativity tells us that the mass of anything travelling at the speed of light, c, is infinite. But the mass (e/c²) of a quantum of light-energy is absolutely miniscule, being in the order of 10^-35 kilogram for visible light. How can this be?

Some physicists seek to solve this paradox by assuming that the photon has zero mass in its own stationary rest-frame. But, in relativity, it is axiomatic that light - hence the photon - has the velocity c in all reference-frames, so that the photon is never stationary but always travels at the speed c. No attempt to make sense of this conundrum of the 'enigmatic photon' has ever succeeded.

The commonsense thinker might suppose that the answer to these paradoxes and conundrums would be simply to cancel the presuppositions that led to them. That is how reason works in ordinary workaday situations, including courts of law. People come up with various theories as to how a particular problem might be solved, and in logical discussion these theories are all pared-down in favour of just one that explains the situation satisfactorily. Not so, however, in physics, where - in modern physics, especially - theories that were temporary inspirations of their day have become enshrined in the annals of physics. The fact, for instance, that Newton became famous for creating inscrutable in vacuo forces meant that these had to be written into physics for students to inculcate as a condition for graduating in the subject. In the same way, the fact that Einstein (in a moment which he himself regretted) came up with the idea of a 'photon' as a quantum particle of light meant that from then on the 'photon' had to be regarded as a 'fact of nature'. This was despite the fact that not only has the flight in vacuo of this alleged 'light-particle' never been detected but also that it is undetectable even in principle.

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