Matyáš Moravec, Queen's University Belfast

Many of us set ourselves New Year’s resolutions hoping to form better habits. Some of us might want to be more environmentally friendly. Others want to eat better, stop smoking or, if you’re like me, start running more often.

Setting these resolutions relies on the belief that we can change our habits. They are predicated on the idea that what happens in 2022 is not yet decided: it is up to us whether we buy a pack of cigarettes or a pair of new running shoes, right?

We believe that the future is not yet set in stone. But is it possible that everything is preordained? This idea has been explored in many ways, from medieval theology to modern physics .

There is no Big Now

We all understand time as divided into the past, present and future. This understanding, however, was shaken when Albert Einstein came up with his famous theory of relativity in the early 1900s.

Prior to Einstein, the “present” was shared by everyone in the universe: there was a “Big Now”. Before Einstein, I could look at the clock, see that it says 12 noon, for example, and say that a whole lot of things are happening “now”, even for people very far away from me. For instance, while I am looking at the clock in my office, the bells in Belfast city centre are striking noon, a person in London is looking at a bird in the sky, and planets are colliding in a galaxy light years away. We all share one present, one “Big Now”, in which all of this happens.

After Einstein’s discovery, this was no longer true. I could only speak about “the present” from my own perspective on the universe, in my

. There was no longer a “Big Now” stretching across the entire universe. What I observe as happening “now” from my perspective might look very different from another. A Martian travelling past the Earth on a spaceship at an incredibly high speed, for example, might see the clock showing 12 noon in his now, but might not see the bells striking in Belfast just yet. My “now” is different to the Martian’s “now” and what counts as “the present” depends on our individual perspectives.

To use an analogy, “the present” or “now” is just like “here”. “Here” is not one location you can find on a map – it just describes your position relative to your surroundings. My “here” currently includes Belfast, but your “here” probably includes something else, just like my “now” is different to the Martian’s.

Einstein’s discovery has a surprising consequence. My “present” is no more special than the Martian’s (or anyone else’s). If “the present” is just a matter of perspective, then all times should be equal. And if they are all equal, they must all exist, much like the way all cities in the UK exist even though what counts as “here” varies from one observer to another. It would be silly to say that only Belfast exists because I’m observing it here.

But this clearly challenges our belief in an “open future”. If all moments of time exist, does that mean that my staying in bed every morning in 2022 instead of going for a run exists, too? Are future events already “there” without me being able to do anything about them?

God on top of a mountain

Another way to think about this is through the Christian idea that God knows all things past, present, and future. But how does God know the future? What’s the basis of God’s knowing if I’m going to go jogging in January 2022 or not?

The philosopher Boethius offered up a response that would be held as true for more than a thousand years. He said that all things, past, present, and future, exist for God. He compared humans to travellers journeying through a valley and God to an observer standing on top of a mountain above. Whereas we see the bits of the path ahead, God, from the mountain, sees the entirety of the path. All of its segments exist for him. Similarly, God eternally sees my birth, my present writing of this article, and whatever it is that I will do in 2022 and beyond.

This leaves us with a similar problem to the one implied by Einstein’s relativity, one that many medieval philosophers like Aquinas or Scotus recognised. Since God’s knowledge is unmistakable, if God knows something will happen, then it must happen. If God sees which turn the traveller will take on the path, does that mean the traveller’s journey is already decided? If my staying in bed instead of going for a run in January 2022 already exists for God, does that mean that I shouldn’t bother getting running shoes this afternoon?

The future is up to us

If God sees the future and all times already exist, what is the point of even trying to change or setting a resolution?

Those interested in medieval thinking and modern philosophers grappling with Einstein’s relativity recognise that language is the main culprit of this problem. For example, we just said that the future exists “already”. But we have to recognise that the word “already” is just as relative as the “now” or “here”.

In physics, all times might exist, but what happens in the times relative to our “present” still depends on us. The entire chain of events in the universe might exist, but we are still active agents in it: it doesn’t all exist “at once” or “already”. It just exists. And it still depends on how I act now, in the present relative to me.

Similarly, for the medieval theologians, God might see me getting up and going for a run on January 1, but equally see me putting on my alarm on December 31, promising my friend to start running with them on December 20 and heading to the shop to buy running shoes, right now. Regardless of whether the future exists for God, what happens in it is still up to me.

This means, paradoxically, that even though the future exists, it does not exist “already”. And what happens in it depends on what I do right here and right now.

Matyáš Moravec, Lecturer in Philosophy, Queen's University Belfast

This article is republished from The Conversation under a Creative Commons license. Read the original article.