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The fact that we live in time and God lives in eternity leads to all kinds of questions. For example:

  • If God is eternal and outside of time, does he create all of history all at once?
  • Does the fact that what is true in time changes mean that God’s knowledge changes?
  • How can God be eternal and yet incarnate as Jesus Christ at a specific moment in time?

To answer questions like this, we need to think about the nature of both time and eternity.


Three Views of Time

Philosophers sometimes talk about three views of time:

  1. The view that only the present is real (so the past and the future are not real)
  2. The view that the past and the present are real (but the future is not real)
  3. The view that the past, present, and future are all real.

The first view is sometimes called “presentism,” since it believes that there is only one moment that truly exists: right now, the present. On this view, the past and the future don’t exist. The moments in the past once existed, and the moments in the future will exist later on, but right now, the only thing that is real is the present.

The second view is sometimes called the “growing block” theory, since it presents time as a block that grows with the course of events. The events that are in the past are real, as are events occurring in the present, at the leading edge of the block, but future events do not yet exist.

The third view is sometimes called “eternalism.” On this view, the past, present, and future are all equally real. The present is the moment of time that we are experiencing right now. We no longer have access to moments in the past, and we do not yet have access to moments in the future, but they still exist.

Which of these theories is true?


Arguments from Physics

A hundred years ago, Albert Einstein proposed that time is essentially another dimension—a fourth dimension, alongside the three spatial dimensions we experience: height, width, and breadth.

He proposed that, together, these dimensions make up a reality physicists now call “spacetime.”

This concept has served physics extremely well. It makes it easy to describe physical phenomena using equations, and it has proved enormously useful to scientists.

Consequently, modern physicists lean heavily toward eternalism.

The idea of time as a dimension has proved so useful, in fact, that even physicists like Lee Smolin—who wants to revisit the idea—acknowledge it is very hard to imagine an alternative that would make sense. (Smolin talks about this in his book Time Reborn).

It thus seems safe to say that, to the extent contemporary physics is a guide, there is significant support for eternalism.

However, the findings of science are always provisional—never final—so they are not definitive for the question.


Arguments from Philosophy

If the results of physics are not definitive, neither are the results of philosophy.

The debate about the nature of time has been going on since the ancient Greeks began wrestling with the question, and no definitive solution has emerged.

An individual philosopher may find the arguments mounted for one position or another to be the most compelling, but—as on most subjects—there is no definitive consensus among philosophers.



What I’d like to do, rather than proposing an argument from physics or philosophy, is mount a theological case.

I want to point out right up front that the Church does not have an official teaching on the nature of time, and I know orthodox Catholics who take different positions on the matter.

However, I think that what the Church teaches about God has implications for the nature of time.

So let’s look at that.


God’s Eternity

The Church teaches that God is eternal. The Catechism of the Catholic Church states:

We firmly believe and confess without reservation that there is only one true God, eternal, infinite (immensus), and unchangeable, incomprehensible, almighty and ineffable, the Father and the Son and the Holy Spirit; three persons indeed, but one essence, substance or nature entirely simple (CCC 202).

In popular speech, saying that something is eternal means that it lasts for an unlimited amount of time. However, when applied to God, the term “eternal” means something else: It means he is outside of time altogether.

The classic theological explanation of eternity was provided in the sixth century by the Roman philosopher Boethius, who wrote:

Eternity . . . is the simultaneously-whole and perfect possession of interminable life (On the Consolation of Philosophy 5:6).

This means that God’s life has no end (it’s interminable), and that he possesses all of that life all at once (in a simultaneously-whole manner). He does not experience it moment-by-moment, the way we do. God’s life thus is not spread out over time the way ours is, meaning that he is outside of time.

As St. John Paul II explained:

[H]is eternity . . . must be understood as the “indivisible, perfect, and simultaneous possession of an unending life,” and therefore as the attribute of being absolutely “beyond time” (John Paul II, Audience, Sept. 4, 1985).

He went on to teach:

God’s eternity does not go by with the time of the created world. “It does not coincide with the present.” It does not precede it or “prolong” it into infinity. . . .

He is eternal because he is the absolute fullness of being which cannot be understood as a sum of fragments or of “particles” of being which change with time. The texts quoted from the Bible clearly indicate this.

The absolute fullness of being can come to be understood only as eternity, which is, as the total and indivisible possession of that being, God’s own life.

In this sense God is eternal: a “Now,” a “Present,” subsisting and unchanging.

This mode of being is essentially distinguished from that of creatures, which are “contingent” beings (ibid.).

God therefore exists in what theologians refer to as an “eternal now” outside of time, a now where time does not pass from moment to moment. It is thus distinct from the “temporal now” we experience, where new moments arrive and then slip into the past.

A consequence of this is that there is no change in God. There is no progression from moment to moment in the eternal now, and so no change occurs in God.

This appears to have theological implications for the nature of time.

We’ll look at those next.