There is something profoundly amiss between the nature of reality and the ability of the human mind to comprehend it. The incongruity does not arise from mere ignorance, but from paradoxical observations. For instance, single electrons fired one at a time toward a pair of narrow slits can go through both slits simultaneously, as evidenced by the ensuing interference pattern. Yet, this pattern is absent if only a single slit is present or if the passage of the electron through the slits is recorded (Feynman, 1985)! This familiar peculiarity of the wave particle, and the fatal intrusiveness of observing it, is now further compounded by the demonstration that quantum mechanical effects can violate physical “locality” (Aspect et al., 1982; Bell, 1986); that is, the influence of observation can be conveyed at a speed exceeding the velocity of light. These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.
There is something profoundly amiss between the nature of reality and the ability of the human mind to comprehend it. The incongruity does not arise from mere ignorance, but from paradoxical observations. For instance, single electrons fired one at a time toward a pair of narrow slits can go through both slits simultaneously, as evidenced by the ensuing interference pattern. Yet, this pattern is absent if only a single slit is present or if the passage of the electron through the slits is recorded (Feynman, 1985)! This familiar peculiarity of the wave particle, and the fatal intrusiveness of observing it, is now further compounded by the demonstration that quantum mechanical effects can violate physical “locality” (Aspect et al., 1982; Bell, 1986); that is, the influence of observation can be conveyed at a speed exceeding the velocity of light. These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.
If we turn down our light source from 100 million whatever photons a second to, say, just ten a second, we see the problem, if not the screen, very clearly. These last few photons of light head off, one by one, for the screen, some of them hitting the piece of card but the odd one going through a slit. Now, according to common sense, each should be able to land on the screen unaffected by whether the other slit is there-or not. But none of them, no matter how long we wait, will try to land on the dark areas seen in the interference pattern with lots of light. After all, if an individual photon could behave in this way, it might take a long time but, eventually, the screen would record a picture more like the one-slit experiment with the light diffusing evenly, than the interference one. And the individual photons recognise the contradiction. They continue to behave individually as ‘waves’ all on their own. Points where the light particle could go when just one slit is open become unavailable when the other slit is open. (Incidentally, the same thing, scientists have observed, will happen with any small particle-electrons, whole atoms or even molecules will do just as well.) In experiments, the individual particles of light seem to know about the other slit on the piece of card, indeed what is going on elsewhere in the universe. For, in principle at least, the distance between the slits can be any size, and the same interference effect will apply. (Although if the slits were even a metre apart, the screen might need to be on the moon before the deflected light begins to converge.) Suppose we asked our neighbour if we could borrow their particle detector to check whether the light energy is still travelling in ‘whole photons’, rather than splitting into two and going through both slits and thereby getting in and out of phase with each other. We would find, indeed, that it was still travelling as a whole photon, and that this attempted explanation does not fit with observation. But we would find something else too. The mere act of putting the particle detector next to one slit causes the wavy pattern, the ‘interference’ effect, to disappear!
The fundamental laws of Nature that govern the physics of atoms, elementary particles, light quanta, and everything else that is small and light, have been found to fit in one grandiose framework called Quantum Mechanics. The internal logic of this framework appears to be counter intuitive and mysterious, while extremely coherent and effective. In this general introduction the author explains why he feels the need for expressing his views on how to understand these facts, even if many known scientists have already given extensive reviews of numerous ideas and approaches. These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.
We have seen that our whole knowledge of the external world of physics may be pictured as arising from the impact of photons of energy either on our sense organs or on our physical instruments. As these photons occur in such profusion and variety, it might have been hoped that they would give us an almost perfect knowledge of the outer world. Yet, as a means of acquiring knowledge, photons suffer from one very serious limitation. They are indivisible; no experiment has ever revealed a fraction of a photon or given any reason for supposing that energy can be either emitted or absorbed in fractions of photons. Thus the only means which are at our disposal for the study of physical nature suffer from a certain coarse-grainedness. This is of little consequence as regards direct study by our senses, since these are even more coarse-grained. Each sense has its perceptions limited by a certain “threshold of sensation”, and if the stimulus of a physical effect falls below this, the sense in question registers nothing at all. We cannot experience the sweetness of a single molecule of sugar, nor the smell of a single molecule of musk; neither can we hear a bell at more than a certain limit of distance, nor see a star which is below a certain limit of faintness. In general we cannot experience a single photon; thousands at least are necessary to attain the threshold of sensation.
As an earthquake has a main shock and secondary shocks, so too a scientific revolution. In this chapter I discuss some of the lesser but still significant tremblers that shook the foundations of physics since 1925 (the principal shock having been identified by Bell in 1964, following clues left by EPR and Bohm). Then, in “Principles,” ignoring Mr. Feynman’s mixed metaphor, we attempt to understand “how it can be like that.” These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.
Realism emerged at the dawn of philosophy. What manifests itself in observation should exist previously, as potentiality, and the set of potentialities should be inherent in a reality that does not manifest itself. The progress of realism elects the natural world as the sole substance and sole cause and, inevitably, commissions it to give life to the observer. The main reason for incredulity at experimental results is due to something absolute in space and time, to the persistent figuration of a container, which survive in the space-time of relativity and even in the ordinary “background” of quantum mechanics. Quantum mechanics, involving the observer in nature, supports the physiology’s announcement that the mind moves along with the brain. The problem worsens in the case of Parallel Worlds because they sprout from the reader and mysteriously fly away to place themselves in an external and common space.