Science began when Aristotle concluded that for all practical purposes, physical events caused physical events, where “physical” meant material not the nothing of space. Over time, matter was assumed to exist by its own substantiality even when it obeyed “God’s Laws”. Today physics takes the term “physical” to include energy even though light has no mass by saying that energy can transform into matter and giving light a relativistic mass. It sees a physical world of matter/energy that exists by and of itself in a space-time context that is also seen as real in itself by some.
In physical realism, there is a real world out there, apart from us, and it is physical. The physical universe is seen to be all there is because it is real in itself, and so it needs nothing else to sustain it. This ideological belief, that no reality exists beyond physical reality, is sustained by four statements about the physical world, namely that it is:
1. Eternal. What exists by its own substance can be transformed, as when a potter turns clay into a bowl, but cannot be made or unmade by external means. A physical world that was made implies something beyond it, contradicting physical realism. The failure of steady state theory to compete with big bang theory last century cracked this pillar, so supporters patched it by speculating that the physical universe magically arose from nothing or oscillates in a big bounce.
2. Continuous. Matter that self-exists by its own substance must do so in a continuous space and time, or something else would be needed to explain the gaps, again contradicting physical realism. This continuity creates infinities, so supporters had to invent the mathematical trick of renormalization to patch up the problem, a technique Feynman called a “dippy process”.
3. Deterministic. If the physical world is all there is, then everything must have a physical cause. This denies random events such as atomic decay, as a random event by definition has no physical cause. It also denies quantum theory, which implies that every physical event is random to some degree. The patch to this was very creative, being the many-worlds or multi-verse fairy story that every quantum event creates an entire new universe.
4. Self-existing. A physical world that is all there is must self-exist, as that anything else creates it contradicts physical realism. Yet in quantum theory physical events only happen when quantum waves interact so the observation alters the effect and the evidence supports this. The standard model pastes over this crack by postulating virtual particles that appear from nowhere to explain whatever an observer sees.
The four pillars of physical realism and their patches are shown in Figure 1.7. It is interesting that instead of saying God is eternal, all-pervading, all-powerful and unbegotten, we now say that physicality is always conserved, continuous, universal and made of fundamental particles. The terms are different but the effect is much the same. One might as well say the physical world is eternal, all-pervading, all-powerful and self-existing. Physical realism seems more an ideology accepted by scientists than a conclusion of science itself.
Physical realism isn’t scientific if it doesn’t handle the evidence well, and it doesn’t. To believe this today one must also believe that our universe sprang into existence from nothing, that the infinities of continuity can be removed by a mathematical trick, that any photon can spawn another universe and that virtual particles from empty space make things happen. To say that physical realism has a shaky foundation is an understatement, so its time to at least consider a quantum foundation for physics.