Although our body and brain process each sense through a separate system, normally we only become aware of it after the various senses have been woven together. We experience sensation as a whole. We smell a flower in the garden and all at once, it seems, we smell its scent, notice its shiver in the breeze, feel the silk of its petals, hear the crunch of our knee pressing down into the bark mulch of the flower bed and see the faint green haze that seems to rise from its arched turgid leaves. But senses don’t actually work that way. We perceive the world through a limited set of categories that differ sense to sense.

Anne Triesman has described the “building blocks” of vision. These are the basic categories of sight. Out of them comes our sense of seeing. They include: color, size, contrast, curvature and tilt. These are the things we are built to notice quickly. The various combinations of these basic blocks are done serially and this takes processing time. So we can notice the difference between a curved line and a straight line very quickly, but the difference between different shaped arcs takes a little longer. Each of these basic blocks is processed separately; the range of possibilities of the various combinations constrains what we can see.

Like all sighted creatures, what we can see is limited by the structure of our brain and our eyes. Our eyes, for example, can only respond to certain frequencies of light. So we can see within a range of 400 and 700 angstroms. (One angstrom is equal to one hundred-millionth of a centimeter.) We cannot see UV light which falls outside our range, but a hummingbird can. How life looks depends on the relationship between the limitations of the visual perceptual system and the limitations of the conceptual system which then processes the received stimuli.
A frog’s organizational rules of sight, according to Jerome Lettvin include the 1) general outline of their environment, 2) detecting moving edges, 3) the perception of small dark objects and 4) a sudden decrease in light. The balance between the frog’s perceptual and conceptual system conscribes frog lived reality as surely as the same balance conscribes human lived reality.

Perception is an act of physical interpretation: we “compute semblances from sparse signals” We do not perceive the hyacinth, but the curve, the balance between perceivable energy frequencies (which we see as color), by the three different types of cones in our retinas, the general form of the structure, etc. Our brain takes those signals and weaves it together processing the production against stored patterns (memories: cerebral pattern reconstruction) and presenting us with a whole-cloth. This is the visual experience of the flower hyacinth.

All perceptual systems work the same way. Our auditory system has a set of “building blocks” (tone, loudness etc) as does our kinesthetic system (uprightness, depth, direction etc). Two key components to understanding the combined effect of these various systems is to understand that by preference we like “stable, invariable patterns of organization” and that some systems are more (evolutionarily) basic than others. For example, uprightness as a sign of bodily viability takes precedence over visual information because if (as in the experiments of Ivo Kohler, reported in Robert Ornstein’s book The Evolution of Consciousness) special glasses are used to seriously distort vision, an “acceptable semblance” was created within a fairly short time allowing the body to operate well even in conditions where sight would seem invaluable (traffic, for example). The eye presenting an upside down world is interpreted by virtue of the body’s kinesthetic system which is still “saying” Nope. Everything is fine. The body believes this kinesthetic sense and fixes what the eye sees until it agrees with the body.

And here, in uprightness and its primacy over the eye, is the key to spiritual learning. Even though the eye is inextricably linked to our developing sense of self, it still bows to the authority of what the body knows. It is acknowledging this and following the eye’s lead and attending to the body’s knowledge that opens the door to the world of “spirit.” Much of the discipline of attention (spiritual practice) that fuels spiritual or perceptual change results in and from the capacity to begin discerning the various systems of the sensorium. As practice develops and the normally unattended world of the body-speaking begins to be heard, then a mountain is no longer a mountain.