In this day and age of publish or perish history, it grows increasingly difficult to identify the turning point in the development of scientific theory. Every scholar from the past made his or her minor contribution, and every contribution is embellished to the greatest degree by the tenure-hungry ... until finally the course of events is studded with unfamiliar names. It becomes anybody’s guess who was responsible for what breakthrough – which supports the anti-Randian view that Isaac Newton’s steward was as wise and knowing as ol’ Isaac himself, and probably responsible for half the Principia Mathematica, though of course less well known.
Plunging into the subject of optics - even the history of optics - I soon found myself submerged, and waves washing many feet over my head. I am no theoretical physicist. I cannot explain the principles of refraction, or how it is accomplished by the eye. I cannot offer the gentle reader a comprehensive and systematic analysis of optical theory. I simply wouldn't know where to begin. In any case, I fail to see where any of that would be applied to D&D ... but that could be the result of not understanding it.
I have been able to glean from sources that two significant leaps in optical 'theology' were made. First, in a theory proposed by an Arab with the westernized name Alhazen (Ibn al-Haythem, early 11th century), derived from an understanding that every object reflected light in all directions ... but that we only saw the light which happened to be directly reflected into our eyes. Furthermore, objects which were closer had a greater chance of reflecting light into our eyes than objects which were further away - and therefore objects which were further away appeared smaller to us, even though in reality they might be much bigger than objects which were close up. Moreover, the color of the object was subject to inherent qualities of the object reflecting the light.
Second, that light could be refracted so that, depending on the position of the individual, different colors could be witnessed. Theodoric of Freiberg proposed that light was "refracted,' and that as a beam of light changed direction it could produce specific colors depending upon the location of the viewer. If the refracted beam of light did not directly enter the eye, then there would be no evidence of color; but if the refracted beam did directly enter the eye, the viewer could potentially see yellow, orange, red, green, blue ... and so on depending upon the exact location of the individual with respect to the refracted beam. This effect was - is - most familiarly obtained through water droplets in the air, or what is called a 'rainbow.' The rainbow does not cover the whole sky because it's appearance is due to a specific angle created by raindrops that convey the light falling to earth to 'change its direction' and meet your eye. Believe me, this was heavy scientific knock-out theory in the 13th century.
It is, incidentally, the reason the sky is blue.
From these two leaps in optical theory (and at least a hundred minor leaps as described by historical science philosophers) would develop an understanding of perspective ... which in terms of Civilization IV, is the application of light mechanics that enables Astronomy. Perspective is the application of mathematics to the visual angles produced by Alhazem's theory of reflected light. To sum up briefly, being able to measure perspective allows painters and architects - along with a host of other professions - to copy reality with mathematical precision. In addition, the mathematics of perpective allow us to build our own reality to exact specifications ... so that we can lay out how the interior of a building would look before it is constructed. The exterior too, for that matter, along with groups of buildings, streets, civic defenses, roads, water systems, canals and so on, without end.
From a comprehension about the way we see things, we are able to construct things so that they will appear in the way we want to see them. Such as an entire world.
Time to time, I receive a question about the maps I produce for my world along the lines that I could save myself time and effort by ripping off someone else's maps. But as I write this post I am reminded that before I began to draw a single line of the maps themselves I calculated mathematically how the world ought to be hexed, how the various parts of the world would be plotted and to what degree the projection of the actual world would be skewed in order to manufacture the D&D world as I wanted it. It occurs to me that in manufacturing my own world, I could not be restrained by the bias of others who before me manufactured their worlds ... and I would be restrained if I weakened and tried it 'the easy way.' In fact, I would have wound up with something like a Frankenstein's monster ... slapped together pieces of other human beings, rather than a living entity in its own right. Clearly, what I wanted to do was to give birth, and not to concatenate.
Perspective as a mathematical principle is an intrinsic part of the modern human experience (and the Roman experience before the understanding was lost). The testament to its value stands in every direction the reader cares to look. Whether the design is something to be done for a potentially existing thing, or something that will remain forever fanciful, the process of conception is the same:
Look at the whole 'thing' that is to be designed: world, dungeon, system, spreadsheet, what have you. Start by expressing the thing's reality in mathematical principles - don't just draw random lines on a gridded page!
Take a dungeon, and consider those things an architect would consider. How do the residents obtain the things they need in order to live? What arrangements have been made to remove sewage. Would the residents travel a long distance to reach their food, or would it be conveniently located to their sleeping quarters? Where would be the logical location for storage? How many storage locations would be required? There should be particular caches for food and other supplies in defensive locations which could be locked down if necessary in case of invasion.
What are the arrangements in order to allow the residents to get to their weapons quickly? How do they keep from being trapped inside one room, or inside one part of their lair, or inside the lair as a whole? Rather than random secret doors that seem to provide convenient travel for players, how are the secret doors rationally placed to increase the power of the dwellers to defend their lair? How are these doors set so that, once opened to allow access to invaders, they are buttressed to stop invaders from using them?
Instead of a dungeon that's created to be dull-dull-dull-dull-dull-action, how can a dungeon be created so that it hits an invading party from every side in a succession of designed consequences which first induce a party to leave, get out ... and only after that surrenders to the idea that these invaders will need to be killed? How are the traps arranged so as to drive the party into the parts of the dungeon where we want them to be? Like links on porn sites that dump children on the Disney page, how do the traps inside a lair repeatedly dump parties back outside, until they give up trying to get in? How does the compartmentalization of the lair fool parties into thinking they've succeeded in killing everyone, when in fact they've only seen a small piece?
This may seem a long way from 'optics,' but really it is in how you see a thing that is to be created. If your perspective as a DM is to create dungeons which are jolly funlands for players, how do you perceive that your world is anything but a cheap sham like any video game? And if it is a party world for players, call it that.
But if your purpose is to create something that will stand the test of time - if you ache to build the Taj Mahal rather than Disney's Matterhorn - then change your perspective to that of the enemy, those who are actually building the lair for their purposes.
The technological leap in optics is not in the manipulation of light, but in the comprehension of it. Puzzling through the substance of the world one bit of logic at a time, to the point where its possible to understand how a rainbow works even though it can never be touched, handled, moved or applied to anything. It is lifting oneself up from the simplified mechanics of tossing rocks one upon the other and fabricating in your head how those rocks could be arranged so as to produce a standing, soaring tower into the clouds.
Stop looking at what the ground offers. Close your eyes and picture what you want.
Now make it.