I'm getting tired of reading about how some people think other physical dimensions would have to be seen with the eyes in order to exist. The way other dimensions are being conceptualized is inhibiting understanding of the subject. To use a popular phrase, those working in the field need to think outside Euclid’s box. We are conditioned to believe that not only are the Euclidean dimensions the only ones, but they are the only type of characteristics, with the possible exception of time, that can be physical dimensions. We are also conditioned to believe that physical dimensions only exist if we can see them with our eyes. The idea that the eyes see three dimensions is itself a result of conditioning. Each eye actually sends a flat 2-dimensional (width and height) image to the brain. The brain uses differences between the images received from the two eyes as well as visual clues like shadows to add a dimension indicating the length of the distance from the eyes to “see” in 3 dimensions. We’ve all seen babies try to reach out and touch things they are looking out. One reason for this is the developing brain is trying to learn how to judge distance. A baby’s brain may not know anything about inches or centimeters, but it can recognize if something is within an arm’s reach or not. Relying on the eyes to study physical reality has inhibited a scientific understanding before. Copernicus and Galileo had trouble because their theory didn’t conform to what the eyes seemed to be telling the brain. Opposition to Copernicus and Galileo might have been couched in religious terms, but the real problem was differences in perception. The intellectual leaders of the day rejected the new theories because their eyes told them the earth must be flat. They believed that if the earth were round they would be able to see the curvature of the earth with their eyes. People could not feel the earth revolving on its axis and the sun seemed to go around the earth just like the moon so the new theories seemed to contradict reality. People of that day couldn’t go into space to see the earth from space so determining that the earth was round and orbited the sun required ignoring the eyes and relying on math in the form of making calculations based on various observations over time. Recognizing that other dimensions exist will require relying on a strict mathematical examination of reality rather than just what the eyes seem to see. In the strict mathematical sense a dimension is a characteristic or variable. The only information the three Euclidean dimensions provide is length, width and height. If reality consisted only of these three dimensions, we would see a world in black and white only. Our eyes could only determine that something was in a location or not. They could not determine other characteristics of objects because characteristics like color require additional information provided by other variables. The eyes can determine if an object is reflecting or emitting light or if light is merely passing through it, but this characteristic of objects doesn’t depend on length, width or height. One object could not be a different temperature than another in a 3 dimensional reality, because temperature differences require an additional characteristic or variable. Our eyes cannot see gravity or a magnetic field. Yet, we know both exist because we can see or feel the effects of them. When we see something fall off the edge of a table we only see it fall. We do not see the invisible force that draws it to the floor. Gravity and magnetic attraction are not defined by simple length, width and height. The sun occupies a greater 3-dimensional area than earth and has higher gravitational attraction, but a black hole the size of a ping pong ball could have higher gravitational attraction than the sun. The density of matter might determine gravity, but density is a different dimension from length, width and height. Other dimensions would not necessarily have to be “higher” dimensions. There is no mathematical reason that would preclude the existence of various different “spaces” with different numbers of dimensions. For example, there could be an energy space and a matter space. One or more of the dimensions of these different spaces could be unique to that specific space. Other dimensions could be the same with the different spaces intersecting in the shared dimensions. We may perceive reality as 3-dimensional because the various spaces that make up reality intersect in the dimensions of length, width and height. If other dimensions are actually higher dimensions than the space in which we exist, then it would be impossible for the eyes to see them. They could only be perceived indirectly through the projection of their influence on our space. A projection from a higher dimensional space into a lower dimensional space can only possess the dimensions of the lower space.