Name: Did The Future Already Happen? - The Paradox of Time
Uploaded: 2025-05-23T07:37:39.000Z
Duration: 12 min 35 s
Description: Thousands of YouTube videos with English-Chinese subtitles! Now you can learn to understand native speakers, expand your vocabulary, and improve your pronunciation...

Do your past, present, and future all exist right now?

Are you watching this video, being born, and lying on your deathbed at this very moment?

Adverbs of manner

Surprisingly, the answer could be yes, but how can that be?

Imagine the universe like a child painting pictures on paper.

Each picture shows everything that's happening in the universe in a single moment.

With each new moment, all kinds of things occur everywhere.

People are born and die, galactic civilizations expand, you miss the bus, and our universe kid makes a new picture that replaces the old one.

In this way, you get something like a movie.

Only the moment we're in right now is real.

The past is what happened before, now it's gone.

The future is still to come and hasn't been drawn yet.

Each moment being replaced by the next one.

The past is far behind us, the future doesn't exist.

What if the universe kid has already finished all its drawings and stacks them on top of each other?

This way, we get a block, a block of time that contains the whole history of the universe, all moments that have ever existed or will ever exist.

But in this block, in this stack of moments, the past, the present, and the future are equally real and exist at the same time.

The only things that we perceive as real are those things happening now.

How can the past and future be real right now?

The problem is that according to the theory of relativity, they kind of have to be.

Heavily simplified, relativity says that time and space are not separated, but one connected space-time.

When you move through space, you're also moving through the block.

This means time passes differently for different people depending on how they move through space relative to each other.

And this also means that what someone perceives as now is a certain cut along the block, a cut that will depend on how fast they're moving.

So what you think is now is really only your now.

There are many different nows in the universe, and all of them are equally real.

This also means there's no universal past or future.

Imagine three alien spaceships a million light years away.

The first one just hovers in space, not moving relative to you.

You both experience the same now, the same present.

If you had a magical instantaneous internet connection, you could do a video call right now and chat about alien things.

The second spaceship is flying away from us at 30 kilometers a second, about three times faster than a human rocket.

It's moving differently through the block of time than you are, which means its now is different from yours.

With the magical internet, the aliens can talk to your ancestors in 1924, when humanity was discovering the first galaxies outside the Milky Way.

The third spaceship wants to visit Earth, and is flying towards you at 30 kilometers a second, moving at the opposite angle of the second ship through the block of time.

With the magical internet, the aliens can talk to your descendants in the year 2124, when humanity has already built cities on Mars and Venus.

Relativity is based on one powerful principle, cosmic democracy.

The fact that the point of view of all observers in the universe is equally valid.

But if this is the case, your past, present, and your future all have to exist at the same time, right now.

Because for the different aliens, they all happen in their present.

This means that the distinction between the past, the present, and the future is an illusion.

The universe is not a bunch of things evolving through time, like in a movie, but a static block in which the past, the present, and the future all coexist and are real.

Well, think about a galaxy outside the observable universe, too far away to ever visit or see.

But even if you can't get there and don't see it, it's still real.

But if the past is not far behind us and the future actually exists, then there is no movie.

The universe just is like a frozen block of dead cosmic ice with everything that will ever happen already written and decided.

If all times coexist and are equally real, then the future has to be already written.

But that's not how you experience things.

It feels like you can mold your future with your decisions.

It really feels like you're free to choose to stop watching YouTube to not miss the bus.

But if the future is set in stone, you can't decide anything.

And maybe you missing the bus was already predetermined at the Big Bang.

Except quantum stuff is ruining everything again.

Quantum processes can't be predicted, not even in principle.

Not because we're silly and don't know how to do it.

According to quantum physics, quantum particles are intrinsically random.

For example, if you have a radioactive atom, it could decay at any moment, in the next second or in the next million years.

We can calculate the probability that it will decay tomorrow, but no oracle in the universe will ever be able to tell you with absolute certainty if it will do so or not.

But quantum particles can change the world.

Imagine a radioactive element randomly decays and causes a genetic mutation in a nearby mammal.

And then many generations later, that mutation has led to a weird mix of duck and mammal that makes no sense.

Or the atom decays a day later, and the weird creature will never exist.

If quantum stuff is really uncertain, the future can't be set in stone.

But if the future is an untold story, it can't be real in the same way as the past is.

So what happens when uncertain things, like the decay of our atom, become real?

But before we saw that cosmic democracy makes it impossible to define an absolute now, what's going on here?

It turns out that for every individual object, you, an alien, an atom, the past, the present and the future are always well defined.

Your death will always happen after your birth, never before and never at the same time.

Now you are clearly between your birth and your death.

So for you at least, now makes perfect sense.

If we don't play tricks like going to the other side of the universe and using aliens in funny ways to find out what now means, things again start to look ordered and nice, and individual nows seem to exist.

Maybe the block does not contain the future, and maybe we just imagined it wrong.

Maybe the block is just the past, and a thin layer on the surface is the present.

That surface is not smooth, but bumpy and uneven.

It's been made by joining countless individual nows, each experienced by someone or something in the universe, each equally real and valid.

And all observers do their bit, so cosmic democracy is still true.