This, I maintain, is all you need to know and contemplate in order to anticipate how the human organism will respond to a given situation or stimulus.

To be blunt, we are the sum of our perceptions. What creature isn't? But to really appreciate the ramifications of this rather obvious fact, you have to appreciate the gravity of the situation—literally. Because what intrinsic element of this earthly existence is more of a given? Not even our air do we take for granted as much as our gravity. We can go from place to place and detect a change in air quality or perceive aromas in the air. Gravity does not change from one room to the next, normally. We notice a change in gravity when we go into water, but our senses are prepared for this. We expect it and take it for granted just as we expect gravity to be constant on dry land.

We have eyes to perceive light, ears to perceive sound, a mouth to perceive taste. What sense do we have to perceive gravity? The sense organ most dedicated to gravity would be the inner ear, with its equilibrium-establishing fluid. But every organ is a perceiver of gravity, and highly sensitive at that. Gravity is implied in every system; without it, the body malfunctions.

The body itself is a balance. Downward forces are assumed. We are symmetrical left to right—not perfectly, but practically. Forward movement would be hindered if we had to keep falling lopsidedly in one direction or another. The ability to walk upright and use our hands (some can even do both at once) is what gave humans the evolutionary advantage to survive and become the dominant species of the planet. You can see how balance has a lot to do with this. Falling over a lot can really interfere with your survival skills. Being able to stand up, and look big, and see far, and carry things—now that is worth a little evolutionary juice. We evolved quickly from a species that first moved differently from all the others, then perceived differently, then thought differently, then manipulated the environment differently. (Some would say that we are the only species that thinks and manipulates at all, but not me).

So, all physical and physiological systems are designed around the constraints of gravity. Surely our psychological and cognitive systems are ruled by gravity as well. I propose that gravity, the given of gravity, dictates nothing less than what we perceive as beautiful and good or scary and ugly, or what is right or wrong. It is the underlying real physical force behind all of mankind's motives and upon which every one of our built things is modeled. Gravity's necessities are fulfilled and expressed by the concept of balance, which underlies every rule of design in every discipline.

Have I gone over the top yet?

That's a good one. Over the top. The top is much harder to achieve than the bottom. To get down one only has to submit to gravity; but to go up, one has to resist it. So going up is harder. And going over the top is quite a stretch. One might consider the effort excessive. I feel tremendous resistance, but I'm still climbing...

Gravity, as already mentioned, contributes to the human design, symmetry. The symmetry of our limbs is further elaborated by our sense organs. We have stereoscopic vision and stereo hearing. But we also have directionality. We need both directionality and stereo perception to orient ourselves in space. Without directionality, how would we distinguish between our two symmetrical halves, our right and our left?

We have a top and a bottom (not to mention an in and an out, also determined by gravity) and we have a front and a back. Front is front because our sense organs are focused that way. We know a lot more about what's in front of us. That's what we tend to. We are quite blind to what's behind us. That's where the fearful things lurk. And if we look over our shoulders too much to ward them off, we might lose our balance, stumble and fall. Ahead is safe and behind is dangerous. (Not to mention that intake occurs frontally; output, from the rear.) Front is good and back is bad.

Up is transcendent and down is just inevitable.
Birds are magical and worms are icky.
The brain is a noble organ and the belly is base.
I could go on and on.

We are directional beings and implied in that is that we are dual beings. Our consciousness is a continuing process of holding contrasting truths in balanced opposition while we evaluate every new stimulus as a function of where it falls on the continuum of right to left, front to back, up to down, light to dark, and good to bad.

Yes, we have grown beyond the perceptual process as physiological feedback loop, into a cognitive process that imposes meaning and evaluates action in an egocentric system. I'm just saying that we think we're conscious and acting freely, but mostly we're still operating on the same autonomic response principle of "Light, good; dark, bad" that our hominid precursors relied on. We're just a lot more cocky about our judgments; or alternately, a lot more hung up about decision-making. The world of night is not a scary place for us, need not be. And anyway, if a tiger were waiting to devour us in the jungle behind our back door, that would make the decision to stay in and watch TV pretty obviously a good one; but the choices confronting us are often less about physical safety and more about feeling good about ourselves. I have no idea what Uncle Sapiens would say to that.

Personally, looking at looking at the world as a perceptual construction gives me a feeling of lightness and liberation. We're not really evil or base. We are stuck to this ball of dirt by forces beyond our control, but not beyond our perception. When we notice where our vocabulary comes from, and where our thoughts come from, and where our fears come from, our likes and dislikes, we can begin to contemplate change.