If all that we ever know are the sensory images that appear in our minds, how can we be sure there is a physical reality behind our perceptions? Is it not just an assumption? My answer is: Yes, it is an assumption; nevertheless, it seems a most plausible one.

First, there are definite constraints on our experience. For example, we cannot walk through walls. If we try to, we suffer predictable consequences. Nor can we, when awake, float through the air or walk upon water.

Second, our experiences generally follow well-defined laws and principles. Balls thrown through the air follow precisely defined paths. Cups of coffee cool at similar rates. The sun rises on time.

Third, this predictability is consistent. We all experience similar patterns. The simplest way, by far, of accounting for these constraints and for their consistency is to assume that there is indeed a physical reality. We may not know it directly, but we believe it is there.

To reveal the nature of this underlying reality has been the goal of much scientific endeavor. Over the years scientists have elucidated many of the laws and principles that govern its behavior. Yet curiously, the more deeply they have delved into its true nature, the more they discover that physical reality is nothing like what we imagined it to be.

This should not be too surprising. If all we can imagine are the forms and qualities that appear in consciousness, then these are unlikely to be appropriate models for describing the underlying physical reality.


For two thousand years atoms were believed to be tiny solid balls—a model clearly drawn from everyday experience. As physicists discovered that atoms were composed of more elementary, subatomic particles (electrons, protons, neutrons) the model shifted to one of a central nucleus surrounded by orbiting electrons—again, a model based on experience. An atom may be small, a mere billionth of an inch across, but subatomic particles are a hundred thousand times smaller still. Imagine the nucleus of an atom magnified to the size of a grain of rice. The whole atom would then be the size of a football stadium, and the electrons would be other grains of rice flying around the stands. As the early twentieth-century British physicist Sir Arthur Eddington put it, “Matter is mostly ghostly space.” To be more precise, it is 99.999999999% empty space.

If physical reality is mostly empty space, why does the world seem so substantial and unyielding? Why doesn’t the 99.9% empty space of my hand simply pass straight through the 99.9% empty space of the table it is resting on? The simplest way of explaining this is that the electrons spin so fast around the nucleus, they create an impenetrable shell through which other particles cannot normally pass. Picture a person swinging a weight around herself on a piece of string; you can never get close enough to touch her, because the circling weight keeps you at bay. In a similar way, when two atoms meet, their electronic orbits stop them from passing through each other, and they behave as if they were solid balls.

With the development of quantum theory, physicists have found that even subatomic particles are far from solid. In fact, they are nothing like matter as we know it. They cannot be pinnned down and measured precisely. Much of the time they seem more like waves than particles. They are like fuzzy clouds of potential existence, with no definite location.

Whatever matter is, it has little, if any, substance. ▼

From From Science to God: The Mystery of Consciousness and the Meaning of Light, © 2002 by Peter Russell. Reprinted with permission of Elf Rock Productions.

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