Where and When?

Knowledge can be defined as patterns noticed in our perceptions. Underlying specific bits of knowledge are general assumptions like substance and cause-and-effect.

Two other assumptions that guide our interpretation of the world are space and time. If someone in the room sneezes, and I think about the sneeze, my mind automatically presents the idea of "sneeze" along with where in space the sneeze happened and when in time it happened.

What exactly do we mean by these concepts "space" and "time"? The question challenges philosophers and scientists alike.

Space and time give order to the stream of our perceptions. All our sights, sounds, smells and feelings are placed on an imaginary grid in our mind, putting the chair "over here" and the wall "over there," the sneeze "now" and the itch "then."

Because the preconscious brain automatically arranges bits of knowledge this way, it is easy to make the mistake of believing that space and time are external.

Scientifically, it is rather easy to smash that idea. Scientists might not have concrete proof, but they generally believe that conscious experience occurs within the brain. When we see a wall, the wall might be outside our brain, but the sight of the wall is inside our brain.

Therefore, all our sights and other sensations are contained within a fairly small area. Whether we are staring at the walls of a claustrophobic prison cell or at the vast expanses of a clear night sky, the vision is contained in the same small area of our brain.

It should be obvious that, while our perceptions might line up in some way with an external space and time, the space and time that we perceive is internal. A good analogy is speech and writing: One corresponds to the other, but they are completely different in form. Space-and-time might be an internal form of writing which corresponds to something quite different.

Thinking about depth perception -- using vision to determine how near or far an object is -- can illuminate how space-and-time are internal.

Our vision from either eye is two-dimensional. The brain infers and creates the third dimension (depth) by clues in the image (such as perspective) and by noting the differences between the images from each eye.

This depth perception can easily be fooled. An object seen in a mirror looks as if it is "beyond" the mirror, when its image actually lies on the surface of the mirror. Specially filmed movies can give the illusion of depth when viewed with 3-D glasses. A painting or photograph can give the illusion of depth. And so on. Our perception of depth does not directly correspond to something outside of us; it is created within us.

Because our internal depth perception generally "works" for guessing how far away something is, we assume it lines up in some way with an external reality, but this is an unnecessary assumption. All we can justifiably say, is that it helps us predict what our perceptions will be, not that it corresponds to some external truth.

Science has another trick up its sleeve. Our internal space and time differ in important ways from the space and time theorized and measured by science.

To science, space and time are fundamentally the same, just different dimensions of a single continuum. Internally, space and time are interpreted as completely different and separate things.

Also, to science, intervals in space and time are relative: Two people travelling at different speeds could measure different intervals between the "same" events. Internally, space and time appear to be the same for everyone: An inch is an inch.

Space and time are useful tools. Our mind uses them to order our perceptions, and in everyday life, they usually "work" to help predict perception. But they are a blunt tool, and inside our mind.

It is unnecessary and unjustified to go beyond this, and claim that space and time are characteristics of an external reality.

Next: Logical Conclusion