Thursday 3 December 2015

The point of one of the seminal books of our time, Kuhn’s The Structure of Scientific Revolutions, is that even in science, the most rigorously logical and real, material-world-grounded of fields, there are no certainties. All the models of reality ever constructed by the human mind have undergone revisions or even total overthrow in the past. There is absolutely no reason for us to assume that any of our culture’s mental models of reality at any level of resolution—from the subatomic, to the human-scaled, to the cosmic—will be used to guide scientific research a century from now. There is nothing in the idea of an electron that is immune to being superseded by another, more useful, scientifically effective idea, any more than there was in the ideas of the ether or phlogiston—two scientific ideas that are now obsolete.


  
                                     Artist’s conception of atoms inside a strontium clock


And electrons themselves? Will they cease to exist? Why, that’s absurd, you say. Actually, it isn’t at all. Quantum physicists are investigating something much more radical—that electrons were never there in the first place. Previous generations of high school children were taught to draw the atom or of the electron in a model that resembled our solar system; at the time, it was a useful model of subatomic reality. New models of the atom that have been developed recently cannot be drawn at all.

The waves of light that enable humans to use vision as a primary sense are longer than the dimensions of this hypothetical atom or electron. “What does an electron look like?” is an incoherent question. Electrons don’t “look” like anything we can imagine, even if we could pool all of the seeing, understanding, and imagining that our species has ever done. That solar system–like model of the atom is merely a useful model that has enabled some scientists to do calculations and make predictions about the phenomena these hypothetical particles will produce at the level that is observable to us if we prod those particles in certain ways that are available to us in our laboratories and cyclotrons.

But no physicists really think clouds of tiny bullets are whirling around down at the subatomic level. That model has had its uses, but we must not become attached to it. Its day is all but up, and new results are defying many of the ideas and assumptions that it, for so long, has implied.

However, what matters for the purposes of this book is that the quantum model of reality, even if we can’t picture it, has profound implications for our world view. It thus has profound implications for our ethical beliefs, values, cultural morĂ©s, and patterns of survival-oriented behavior.

In the quantum world view, events in reality cannot be pictured as coming in predetermined, connected sequences of cause and effect, but they aren’t random either. All events can now be seen as governed by rules of probability. Which subatomic particles will jump to other energy levels at any given nanosecond can be described only by laws of probability; all larger events are shaped by those subatomic particles.

Normally, an event or an object seen at our level of reality is the average of quintillions of subatomic events. Most of the time, the events we see at our level, the macroscopic one, are high-probability macro events, and they fit together to create the classical, Newtonian pictures and patterns we’ve seen over and over and have come to expect of everyday life.

But quantum theory leaves open the possibility that once in a while, when enough unusual events at the subatomic level coincide, they cause an event at our level—a hurricane, a supernova, a tornado, an avalanche, a failed bolt in an airplane, a mutation in a bacterium, or a sillytumble (okay, I made that up). None of these events is “uncaused”; they all have causes. The problem with the Newtonian worldview is that the causes aren’t neat sequences of earlier events. In principle, we can’t predict these outcomes in advance because we can’t calculate the sums of all the influential links in the causal chain. Weird things can and, sometimes, do happen.

And it’s not just that too many factors are involved. Even simple Newtonian systems with only two or three objects and forces acting on them evolve in ways that defy our best computer models. The possible results of the system depend on initial conditions of all parts of the system. Minuscule changes, some of them quantum changes, in any of these parts at any time during the unfolding may lead to any one of zillions of very different outcomes. The possibilities rapidly become, in practical mathematical terms, incalculable.
 

  
                                         Hurricane Dennis approaching Pensacola, Florida


For example, we can only say after the hurricane has passed that five days before it hit, some of our models had been indicating near-certainty levels of the hurricane’s making landfall on the Florida Coast. Then, the evolving odds that it was going to hit a specific site—for example, Pensacola—began to approach 60 percent on Friday and 95 or 99 percent by Sunday. Tiny jumps by particles, even some subatomic ones (what physicists call the “butterfly effect“), right back to the hurricane’s genesis off the coast of Africa, favored and eventually selected one outcome over all of the other possible outcomes.3


In this hurricane scenario, gradually, a winning-outcome candidate emerged. But before it hit, which outcome that would be was not just unknown; it was unknowable. Unlike the Newtonian/Enlightenment world view, the quantum worldview says that the outcomes in real-life sequences of events are in principle never certain, but are always to some degree predictable in the exact sense of that word.

No comments:

Post a Comment

What are your thoughts now? Comment and I will reply. I promise.