Is it possible that the human mind cannot fathom the reality of time? Is it ultimately impossible to understand how time can be controlled and traveled through as a fourth dimension?

These are interesting questions. The film "Interstellar" attempts to explore such questions, asking itself how time would act as a fourth-dimension. The movie deviates from some more realistic concepts in defining gravity as its fifth dimension, but its exploration of time travel is groundbreaking in its visual presentation of the fourth dimension: time.

In the film, the protagonist moves from time stream to time stream—when he misses his daughter’s departure from a room, he hasn’t missed his opportunity; he can simply move sideways across time to meet her before she leaves. The presentation is beautiful; time is parallel. But how can the human mind comprehend that? If one left the present to visit the past, wouldn’t the present have already been defined by the past?

Is everything one does in the past already rippled through to the present, making any change in the past irrelevant to the present given that the present has already been shaped by the past? It is interesting to explore. If time travel were possible, what would differentiate the present from the past? Any moment in time one traveled to would be their present—past is relative to one’s position. And if that is true, then, theoretically, the “past” could be merely a direction—like forwards or backwards—and not a location. Present is constant. The past is a there; once you’re there, to you, you’re here.

There is an author named Piers Anthony who specializes in the strange, from science fiction to fantasy to erotica. His writing is unique and sometimes provides great, strange insights into the human condition.

In his book "God of Tarot," he defines a characteristic of humanity in comparison to an alien species:

In our [alien] framework, artificial hydrofusion is—or was—inconceivable. We are a protean, flexible species. We do not think in terms of either magnetics or lasers. We are adept at flexible circuitry, at the sciences of flowing impedances. Thus, for us, matter-mission technology is a natural, if complex, mode. You Solarians [humans] are a thrust culture; you poke with sticks, thrust with swords, and burn with fierce, tight lasers. For you, laser-controlled atomic fusion is natural (p. 48).

And later on:

Man had been incapable of conceptualizing any physical velocity faster than that of the speed of light in a vacuum. Man's mode of thought simply could not admit the alien possibility of instantaneous travel; therefore that science had been out of the question. Thought, not physics, had been the limiting factor (pg. 49).

Anthony’s analysis is curious, regardless of whether he formulates it for the purposes of the book or as a reflection of his personal beliefs. Perhaps mankind cannot fathom the implications of time being relative. Maybe our world view, unable to understand the sheer scale of space travel and light speed, is the "limiting factor" in our development. It is probable that only a small portion of the general population understands Einstein’s Theory of Relativity. I certainly don’t.

Time seems to be a dimension that is beyond our control, for the time being—no pun intended. Perhaps this is a good thing. I believe our mortality as human beings lends us to acts of great and terrible self-sacrifice. With time travel, our mistakes would be repairable, without consequence. But maybe even this assumption is indicative of our incapability to understand time as a dimension: if I could repair every mistake, would they ever occur at any time if I always repaired them in the past? Strange thoughts, but I comfort myself with this: as my life is finite, its passing is all the more valuable.