It would then be quite interesting and significant to think in terms of what Zen means by the gateless gate, or the door which leads from nowhere to nowhere, or the wonderful path that leads from itself to itself. These mysterious terms, which sound at first like ridiculous contradictions, actually belong among those koans which are essential to man’s subconscious experience of the Zen mystery. In the story of the red torii, we have this mysterious gate which can be approached from either side, and leads only from the area where you were to the area where you will be, and nothing demarks them except the gate itself. You step from the same to the same through a doorway. To many persons, this gate leading from yesterday to tomorrow, through the mystery of today, is a gate of hope. The individual who has strong, integrated beliefs and convictions looks forward to tomorrow as the time of potential achievement. It is therefore a happy journey through an imaginary portal, for actually there is no gate. Yesterday, today, and tomorrow are bound together in a unity that is indissolvable; but man divides them.

In ancient times, it was held that the phoenix was the symbol of time, of cyclic existences. It was the symbol of the coming of the great blessing of opportunity through time. As the phoenix perch, the torii therefore becomes a time symbol, and time is a gate leading everywhere from everywhere. It is a gate that we have built without a wall on either side of it. It is a hypothetical gate dividing the past from the future. Yet there is no division, for even as we build a gate, the past and the future are mingling again, and that which was the future is flowing into the past. Thus, this gate is a purely psychological symbol. It is, however, a symbol which leads in several directions, although usually so placed that man may perceive through it either the rising or the setting of the sun, perhaps both. This rising or setting of the sun, as seen through the gate, would indicate, therefore, that the gate essentially represents, at least in our exterior thinking, the journey from the east to the west, or perhaps from the west to the east again.

The journey from the east to the west is, in terms of Spencerian philosophy, the involutionary process of man; the journey from the west to the east, the evolutionary process of man. Therefore, the great journey home is the journey back to east. The journey away from home, the journey of the prodigal son, is from east to west. Thus, the gate can represent the two directions of this journey, because the gate is so constructed that it has neither front nor back. Therefore, it becomes a symbol of a gate leading in either direction.

In Buddhism, when it more or less took over the symbolism of many of the old Shinto beliefs, this gate became something else again. It then became the symbol of man’s mental focus. It became the symbol of the mind which leads, through itself, either into illusion or into reality. It also became the sensory gate, by which the bundle of the six senses constituted a doorway leading in both directions: either from within outward—by which man passes from theory to practice, or from the outside inward—by which he passes from practice to theory; the direction depending upon whether he prefers to regard himself as a Platonist or an Aristotelian. Again, this double gate signifies the two directional motion of which man is potentially capable and of which, to a measure, he is constantly making use in his journey of life.

Let us now imagine, for a moment, that the individual today, in his present condition, stands at the Pythagorean crossroad—the celebrated “Y.” This is the path that breaks like the branches of the letter Y, and represents the two-fold path—the upward and the downward path. These paths represent courses of action, and also attitudes with their inevitable consequences. Let us say, for the moment, that the individual is delicately poised on the horizontal line of the now, overshadowed in one direction by the overwhelming majesty of the “above,” and looking downward with some terror into the dark, uncertain, shadowy depths of the “below.” These two directions have always played a large part in religion. One thing, however, which neither this man, in his present poised position, nor psychologists in general, have as yet realized is that, in a mysterious way, the above and the below, the east and the west, the up and the down, the in and the out, are all, in turn, enclosed within a vast hypothetical sphere of identity. All division, or difference, exists within unity; but unity itself is never divided. The grand cell of existence, within which all other cell fission takes place, is never divided. The division occurring within it does not separate it, nor cause it to become two totalities, which would confront us with such problems as two first causes. This cannot exist.

Manly P. Hall, Excerpt from Lecture 20 - "Gateway to Infinities: Journey from the Personal to the Universal", delivered July 31, 1960, pages 12-14 of 20.