In our everyday lives, time is a constant property of existence, continuously flowing from past to present to future. We could not consider a timeless reality, for time is merely the measurement of change.

As obvious as this may seem, this definition does not do justice to the philosophical problems associated with time.

The Dichotomy

Many important philosophers throughout the ages have concluded that time is nothing other than the mind’s attempt to create a cohesive reality. Zeno, a student of Parmenides, proposed that certain paradoxes render the notion of time as a mathematical impossibility. The Dichotomy is described as follows.

Suppose that someone (we’ll call her Ellie) intends to walk from her house to the park. To walk the complete distance to the park, Ellie must first travel half of the distance. Once she’s reached the halfway point, she must then travel half of the remaining distance while progressing towards the final destination. This pattern repeats: Ellie must continuously reach the halfway point between her current position and the final destination. Thus, she must cover an infinite number of finite distances, which is impossible. Nonetheless, we know that she will reach the store and, therefore, we realize the paradox.

Zeno’s conclusion is that time does not flow from past to present to future. Instead, he insists that time and change are illusions. To understand his perspective, trying imagining a world absent of timekeeping. To Zeno and Parmenides, the present moment is all that is. They believed that considering past and future events as real was in contradiction to what is real: the present moment.

(See also: Achilles and the tortoise, Arrow Paradox)

St. Augustine’s Theory of Time

Augustine was also perplexed about the realness of time, though he approached it from a theological perspective. Augustine was bothered by God’s existence within time. If God had created the universe, then why did he decided to create it at one time rather than another? If God is an eternal being, why would he decide to create the universe “now” rather than “then?” He conjectured that an omnipotent being must have a good answer to this question.

In an attempt to resolve this bizarre question, Augustine concluded that time must be a human invention. He proposed that memory and anticipation give our experience its temporal dimension, i.e. our sense of the flow of time. We remember the past and anticipate the future. Therefore, without the ability to remember the past, would it really exist?

Static Time, Causality and Free Will

By default, we think of time as dynamic: it flows from one event seamlessly into the next. Every pair of consecutive time-events are connected through cause and effect (causality), which is why we can make accurate predictions about the world utilizing mathematical equations. This perspective of time also allows for free will, as we play an active part in changing the future.

In contrast to dynamic time is static time: the theory that things simply are as they are and that the distinction between the past and the future are irrelevant. Unlike dynamic time, static time is able to make absolute statements about time. For example, instead of stating that “a certain event will occur in five days,” which will be a false statement tomorrow, static time would specify that “a certain event occurs on June 27, 2014,” a true statement regardless of when it is stated.

An example from Wikipedia describes the distinction between these two theories best:

Essentially the universe is regarded as akin to a reel of film — which is a wholly static physical object — but which when played through a movie projector conjures a world of movement, color, light and change. In the static view our whole universe — our past, present, and future are fixed parts of that reel of film, and the projector is our consciousness. But the ‘happenings’ of our consciousness have no objective significance — the objective universe does not happen, it simply exists in its entirety, albeit perceived from within as a world of changes.

Unfortunately, Einstein was a proponent of the static theory of time. If he is correct, then our notion of free will is obsolete. Instead of making decisions, we simply follow a predefined script, much like the characters in a movie. Because of this psychologically damning conclusion, most theologians reject the static theory of time. (Ironically, the static theory would allow for God to “know” the future.)

Conclusion

The Big Bang is commonly accepted to be the beginning of our universe. Unfortunately, the laws of physics break down at the Singularity, which means we can’t calculate what was before the Big Bang, if anything. As Augustine mused, wouldn’t it be illogical for there to be nothing before time? Wouldn’t this equate to getting something from nothing?

Stephen Hawkings has proposed that time should actually be thought of as a boundless entity, like a sphere. He believes that the “beginning” of time is akin to the North pole: it would be ridiculous to ask what is north of the North pole; the question just doesn’t make sense. Despite this analogy, a singular “beginning of time” isn’t easy to comprehend, let alone accept. The alternative, an infinite universe without a beginning, isn’t very satisfying either.

There is a silver lining: regardless of what time actually is, our experience of it is consistent and predictable. We may say things like “today is going by so slowly” or “this year is flying by” but we fully understand that these sentiments only reflect our attitudes toward time, rather than a variation in time itself.