Sean Carroll at Cosmic Variance recently commented that the recent history of dramatic revolutions in physics, together with the incomprehensible but widely covered debates over string theory and other physical theories at the frontier, tend to make people think that the foundations of everyday physics are much more volatile than they really are.
He makes a fairly basic point, one that I would guess is accepted by the vast majority of scientists, and yet this point is surprisingly controversial in popular science discussions:
Obviously there are plenty of things we don’t understand. We don’t know how to quantize gravity, or what the dark matter is, or what breaks electroweak symmetry. But we don’t need to know any of those things to account for the world that is immediately apparent to us. We certainly don’t have anything close to a complete understanding of how the basic laws actually play out in the real world — we don’t understand high-temperature superconductivity, or for that matter human consciousness, or a cure for cancer, or predicting the weather, or how best to regulate our financial system. But these are manifestations of the underlying laws, not signs that our understanding of the laws are incomplete. Nobody thinks we’re going to have to invent new elementary particles or forces in order to understand high-Tc superconductivity, much less predicting the weather.
In a follow-up post, Sean responds to some of the crazy reactions to this fairly obvious claim. “Seriously, the laws underlying the physics of everyday life are completely understood:
Take consciousness as an example. Obviously there are a lot of things about the workings of the human mind that we don’t understand. So how can we be so sure that new physics isn’t involved?
Of course we can’t be sure, but that’s not the point. We can’t be sure that the motion of the planets isn’t governed by hard-working angels keeping them on their orbits, in the metaphysical-certitude sense of being “sure.” That’s not a criterion that is useful in science. Rather, in the face of admittedly incomplete understanding, we evaluate the relative merits of competing hypotheses. In this case, one hypothesis says that the operation of the brain is affected in a rather ill-defined way by influences that are not described by the known laws of physics, and that these effects will ultimately help us make sense of human consciousness; the other says that brains are complicated, so it’s no surprise that we don’t understand everything, but that an ultimate explanation will fit comfortably within the framework of known fundamental physics. This is not really a close call; by conventional scientific measures, the idea that known physics will be able to account for the brain is enormously far in the lead. To persuade anyone otherwise, you would have to point to something the brain does that is in apparent conflict with the Standard Model or general relativity. (Bending spoons across large distances would qualify.) Until then, the fact that something is complicated isn’t evidence that the particular collection of atoms we call the brain obeys different rules than other collections of atoms.
For some reason, people tend to be drawn to the mysterious solutions to confusing phenomena, over the more prosiac (but more likely correct) answers. Consciousness is commonly abused in this way: people would rather believe that consciousness is the result of some poorly understood but biologically unique quantum phenomenon rather than being the result of some very complex combinations of ordinary cell biology.
The result, Sean argues, is that we miss the significance of what basic physics in the everyday realm has achieved in the last 100 years:
A hundred years ago it would have been easy to ask a basic question to which physics couldn’t provide a satisfying answer. “What keeps this table from collapsing?” “Why are there different elements?” “What kind of signal travels from the brain to your muscles?” But now we understand all that stuff. (Again, not the detailed way in which everything plays out, but the underlying principles.) Fifty years ago we more or less had it figured out, depending on how picky you want to be about the nuclear forces. But there’s no question that the human goal of figuring out the basic rules by which the easily observable world works was one that was achieved once and for all in the twentieth century.
And the key phrase here is “once and for all.”
The Finch and Pea 