I’ve devoted a lot of time and thought to this idea of multiple personal universes, alternate subjective realities. I am a materialist. I am convinced that the world, reality, the universe, whatever you call it, is a purely mechanistic phenomenon. I am certain there is nothing spiritual or mystical behind the doors of perception. But I am also aware that that my only model of this universe of space, time, matter and energy is my own consciousness. I perceive various forms of energy through my senses, and I process them internally using a brain which I am sure is nothing more than a bag of chemicals and electrical discharges. I then interact with this external reality through my muscles and (indirectly) by communicating with others. I may be a part of this universe, no different in principle from the minerals in the soil or the gases in the atmosphere, but the only thing I am really aware of is my own consciousness. Everything else is a dream, a conjecture, an ongoing lucid daydream.

What I must reconcile is the idea of a universe of classical, quantum and relativistic phenomena, the world of the physicist, with the only thing I really can experience directly, with no intermediary agent, through the conscious mind: the soul. I am fascinated by the idea of reality, and why we seem to have different realities. We know that others, faced with the exact same evidence as we, often come to different conclusions. Why should this be? They can’t all be idiots! We perceive the world differently, and we view it in many different ways. In spite of that, we all seem to be able to function somehow, even when our models of reality seem so different, even contradictory.

My parable of the characters in an elementary school, each one reacting to the same environment with totally distinct internal models of that reality, is one attempt to communicate this paradox.Let me try another metaphor.

Consider a historian contemplating the long-term evolution of human civilization, its past and future history, as well as some attempt to develop a theory to explain its present condition. Think of it as Hari Seldon working on his psychohistory, to use an Asimovian paradigm. This scholar will attempt to bring other disciplines and branches of science to aid his research. He will apply knowledge of politics, economics, sociology and anthropology to try and gain an insight into why people act collectively the way they do. This is the first level.

But collective behavior surely cannot be understood without a thorough knowledge of individual behavior, so the discipline of psychology must certainly be applied as well. We also know psychology is also very much a product of our culture and society and how they evolved through time, influenced by all those level one considerations. The psychological reality is the second level.

I personally feel the social and behavioral sciences are all in a very primitive state of development, and conclusions derived from them must be taken skeptically. But let’s forget about that for the time being. We must further concede that our psychological behavior is very much influenced by our biological history. We are animals, and we carry evolutionary baggage from a long line of other animals back into deep time. This biological dimension is the third level.

But what is biology but chemistry (the fourth level) and chemistry is nothing but physics (level five). And this is only a broad sketch of the required map. For example, organic chemistry is a subset of chemistry (level 4.3?) and quantum chemistry (level 4.7) is intermediate between levels 4 and 5, and below the physics level we have all the mumbo jumbo of particle physics. No doubt there are higher levels, and other intermediate levels. They all contribute to the final product.

In short, to properly understand the realities that add up to what we call human history, we must consider everything that contributes to it. We need to study quarks and electrons to fully understand why the War of 1812 was fought.

Of course, we are obviously losing our way with this line of argument. We don’t need to understand everything to know anything. Atomic theory may be essential to the structure of reality but we don’t need to know it in order to write the tax code, or to organize the Army, or plan a wedding. In fact, expertise in atomic physics is no guarantee we are even capable of learning how to do any of those things. The universe is not organized that way. Science is a microscope, or a telescope. It shows us details, but obscures the overall structure and the interconnections. The field of view is too narrow to show all the connections.

In short, we have learned to consolidate, condense, and otherwise simplify reality a great deal. And we have devised more manageable models of it suitable for our purposes. And we have learned to ignore the unessential. We can manage highly complex systems quite effectively without really understanding at all how they function in detail. Like our students and teachers at the elementary school, we cope without a full understanding of the universe around us, and we often have different, even conflicting, views of that universe. We humans are quite good at this, and we seem to get better at it as we get older. We learn how to deal with complex situations, we develop an intuition about them, and very often we can’t explain, even to ourselves, how we know what we know.

Again, like the faculty and student body of our elementary school, we all manage to function in our own individual universes, even though they are not the same universe at all. We live in a subjective reality that is only tangentially related to so-called objective reality. I use the term ‘so-called’ deliberately. I am starting to arrive at the conclusion that objective reality is an illusion. We derive some comfort from it, but there is no such thing.

In this kind of fluid personal cosmology, it is very easy to transpose techniques and concepts, even terminology, from one level of reality and misapply them to another. The electrons orbiting the nucleus are NOT a miniature model of the solar system. The resemblance is purely coincidental, and ultimately misleading. The techniques and insights of the physical sciences are of very limited use in biology, and almost totally worthless in the social sciences. You don’t need the tiniest bit of mathematics to understand how natural selection works. In some cases you can assume light is a particle, in others a wave, and in some cases neither. And you can navigate ships and predict eclipses even if you believe the earth is the center of the solar system.

Mr Spock didn’t know what he was talking about; which was one of the major lessons of Star Trek, wasn’t it? It’s not that science and logic are wrong, it’s that the two are human activies, subjective human activities. You don’t use game theory to select a wife, but that doesn’t mean game theory is wrong. Whatever that means.