I’ve been noodling on about quantum physics for the past several posts, and I don’t want to beat this dead horse (or dead cat, or half dead/half alive cat) for too long. So let me just sum up what I think I’ve learned by now.
The only firm — or somewhat firm — conclusion I’ve drawn is that quantum objects seem to have more in common with thoughts than with physical things as we normally understand them.
For instance, we don’t imagine a physical object existing in multiple states simultaneously, but we often hold several possibilities in our mind at once, which are resolved into a single choice by an act of will. This collapse of the array of possibilities into a single determinate state corresponds to the collapse of the quantum wave function into a "particle."
We also don’t imagine a physical object ceasing to exist when we are not paying attention to it. But our thoughts do cease to exist when we stop thinking them. Quantum objects, which seem to manifest themselves as physical realities only when we are looking at them, have something in common with the thoughts in our minds, which take shape only when we focus on them.
In the macroscopic world, cause-and-effect operates only in one direction, but in our thoughts we can — and frequently do — reach a conclusion through intuition or a sudden moment of inspiration, only later tracing the thought back to its logical starting point. Quantum objects similarly may be said to spontaneously flash into existence and then retroactively realize their chain of causation.
Quantum objects can be correlated so that they have nonlocal connections — connections independent of space and time. Ordinary physical reality isn’t like this, but our thoughts are. In our thoughts we can effortlessly link a memory from twenty years ago with an event in the present, or link a visualization of a faraway place with the environment we’re perceiving at this moment. Time and space are not barriers to thought. It’s as easy to think about yesterday, tomorrow, or the dark side of the moon as it is to think about the here-and-now.
Quantum waves are probability waves comprised of all possible trajectories of the quantum object. Similarly, the decision-making process in our minds begins with a menu of all relevant possibilities — all the possible courses of action we could take. Some options are more probable than others, but since every option has a nonzero probability, if we were to choose over and over again we would eventually choose all the options. Thus the probability distribution of the quantum wave is paralleled by the probability distribution of our choices.
Quantum objects become entangled with other quantum objects, leading to progressively larger sets of possibilities. Similarly, one decision can become tangled up with other decisions, leading to more and more complex arrays of choices.
Quantum objects ramify — that is, they branch out along multifarious pathways that become increasingly elaborate, until one pathway is selected and the others collapse. Similarly, our thoughts tend to branch out in increasingly complex patterns, often going in many directions at once — until we zero in on one path and dismiss the others from our mind. The branching nature of thought is most apparent in "stream of consciousness," which occurs when daydreaming — that is, when we are not alertly focused. Similarly, the ramifying patterns of quantum objects take place when the objects are not being observed.
How about the famous paradox of Schrodinger’s cat? If we think of the cat as a mental object, there is no problem in imagining it as both alive and dead at the same time. It is no more problematic than our ability to hold two (or more) contrary possibilities in our mind at once. In Schrodinger’s thought experiment, we do in fact hold two contrary possibilities in mind — the cat may be alive, or the cat may be dead. We can entertain both possibilities as long as we have not selected one or the other. Once we select an option, the contrary option drops away (collapses). Seen this way, Schrodinger’s cat does not entail a contradiction or even a paradox (apparent contradiction), because there is no paradox in holding two different possibilities in mind.
What about the relationship between the quantum world and the macroscopic world? In the quantum world, probabilities rule, but in the larger world we have identified seemingly invariable "laws" of nature. But these "laws" may perhaps be better understood as regularities. There are regularities in our thinking, too — habitual, self-reinforcing patterns of thought that crop up again and again. Are the regularities of nature similarly habitual and self-reinforcing? Sometimes nature’s "laws" can apparently be broken, as when some paranormal event like levitation occurs. What we have in such a case is a discontinuity in the normal, habitual regularity. Similarly, when we come up with a new way of thinking about something, this is a kind of discontinuity too. It disrupts the "normal" habitual pattern of our thinking and allows our thoughts to go in new directions.
Finally, thought itself is fundamental, irreducible, in the same way that quantum objects appear to be.
In all these respects, and no doubt others, quantum objects seem to be more like thoughts than anything else we might compare them to. These parallels don’t necessarily prove that quantum objects are thoughts, though they may be. Physical reality itself may be a series of thoughts or thought-forms in our minds or in the mind of God. (This is philosophical idealism.) Or maybe both consciousness and physical reality are expressions of some deeper, unifying reality, and both of them partake of its nature. (This is the philosophical position called neutral monism.) But whatever the metaphysical implications, it does appear that observing a quantum object is akin to making a choice.
Let me be very clear that the choice is simply where the object will manifest — which trajectory it will take. The choice is not the choice between a wave function and a particle. On the contrary, the wave function is the menu of options that exist in the absence of a choice. Once the choice is made, the menu instantly collapses to the single option that has been selected. This is how our minds work in making decisions, and it seems to be how quantum objects work when we observe them.
In fact, instead of thinking of photons, electrons etc. as "objects" that must be "observed," it might be more useful — or at least more interesting — to think of them quite literally as "options" that must be "chosen." Some physicists speak loosely of quantum objects "choosing" which path to take, but wouldn’t it be preferable to say that it is our mind that does the choosing, and the resultant path is nothing more or less than the choice we made?
The alternative is to endow subatomic objects with intelligence and the ability to choose — something David Bohm and others have suggested. But isn’t it more likely that the intelligence and decision-making we observe in the quantum world are really our own intelligence and decision-making at work?
Of course I may be entirely wrong about all this. But this is the only way I can see, at present, of making sense of the otherwise senseless world of quantum paradoxes.