Humans very much depend on the present. Everything we do in
life is done with the understanding that we're doing it right now, whether
we're hugging a friend or recording a YouTube video. We do it in the now and
then it becomes the past. But it might surprise you to find out that in
science, what we think of as "the present" doesn't actually exist.
Only the past and the future do.
When we look into the night sky, we are seeing the past.
Often the distant past. If you look at the Andromeda Galaxy which is just barely
visible to the naked eye in a dark location, you are seeing it as it was 2.5
million years ago because light travels at a rate of 186,000 miles per second
and it takes that long to travel the immense distance between the two galaxies.
This is also true for an object in the room with you. When you look at your phone,
you are seeing it as it was a tiny fraction of a second ago, not as it is right
now. Light, or information, takes time to propagate no matter the distance.
This means that in any direction you look, you are always seeing
the past no matter what. You are not seeing the now. In fact, it's physically
impossible for you to see the now. But it gets worse. It's also impossible for
the now to exist in your brain because it also takes time for impulses to
travel along neurons. And, this doesn't happen at the same rate for everyone.
All of our brains are unique. Each human brain varies in the
time it takes to process the information it receives from the outside world.
This means that your now is different from my now, even if by just a fraction
of a second. Perception is a deep rabbit hole indeed because the differences
between brains covers more than just processing time.
Diagnosable conditions like color blindness aside, you
probably do not see the same colors that I do. How you perceive red is likely
different from how I perceive it, but since there's no way to describe the
color red then there's no way to know -- at least until brain to brain interfaces
become available. Likewise, you don't experience the present at the same time
that I do. The difference is miniscule, a matter of milliseconds, but it's
there.
Intuitively we think of the present like a sandwich filling.
It's wedged between the past and the future, but in reality it's not. It's
actually a completely fake construct of our brain. You can see this by thinking
about what a moment in time really is. When you think about it, the present has
no duration. There is no length of time involved, you're just conscious moving
from one moment to the next seamlessly. We have to artificially make a duration
for it with a clock. In other words, our perception of the present is just a
construct of our brains. It doesn't really exist.
Yet we live our entire lives in this strange juxtaposition
of having memory of the past and expectation of the future and are led to believe
that we're in the present at all times by our brains.
But what is time? If you think about it keeping track of
time is really just keeping track of change. If nothing ever changed, time
would seem to have stopped. As a result, there would be no present because
there would be no change from which to judge it. If nothing changed in your
brains and your neurons simply stopped firing, i.e. stopped changing, the
present would cease for you. So would consciousness. Are time and consciousness
linked? In some ways, yes. At least our notion of time is.
But does time really exist? Well, in some ways it does, and
in some ways it doesn't. Time is thought to be a dimension, one that we always
move forward in. We don't actually know why that is, but I'll leave that for a
future video. If you're talking about time as we perceive it, then it doesn't
appear to exist. But if we're talking time in the sense of physics, it very
much exists. And, whatever it is, it's linked to space itself, hence
space-time. It can speed up or slow down. It ticks at different rates depending
on where you are as far as gravity is concerned and how fast you are moving. If
you're just about to fall into a black hole, then time nearly stops -- for
someone observing you. For you, it seems to tick normally. That's because
everything is relative.
That throws another wrench into the works of perception. That
wrench is Einstein's theory of Special Relativity. Einstein realized that
because everything is relative, two different observers will perceive events
differently depending on where they are. For example, if you were in orbit
watching the earth below you might see two train wrecks, one in Sweden Argentina
This is because the observation of events is relative to the
distances and motion involved and thusly the question of when they happened is
also relative. One person believes the events were simultaneous because she
observed them to be, and the other does not because he observed them and saw
something different. There is no such thing as an absolute frame of reference.
This whole idea gets even stranger when you dig into
philosophy. If the present doesn't exist, and the past is that which already happened,
and the future is that which has not yet happened, then where exactly are we? If
you've watched my video "Is the universe real? Or is it a computer
simulation", you'll know that the universe essentially doesn't exist if
you aren't looking at it. If you remove intuitive notions of time and space, that
idea gets even more murky. There is no when, and there is no is, there is only
consciousness observing changes in space. That constitutes everything we
experience from our birth to our death. But let's take it a step further.
There is actually no way to prove that anything exists
outside your own mind. The only thing you can prove to yourself is that you
exist, everything else could be an illusion. And when you alter perception just
slightly, this becomes readily apparent. Mind altering substances alter the
brain's perceptions and thusly things that do not exist for you and I, do exist
for the person under the influence. Someone on LSD may see a giant blue coyote doling
out words of wisdom and completely believe that it's there, whereas the
onlooker sees nothing. The person tripping can't prove that the coyote exists,
but he certainly thinks it does -- at least until the effects of the drug wear
off.
But, that's a two-sided coin. A sober person also can't
prove that what they are seeing is real to anyone else. This is because every
piece of information you get comes from your senses. Senses can be fooled by
fooling the brain, or making it malfunction. This means that to get anywhere in
life, you must assume that what you are seeing is real. And likewise, the rest
of us have to assume the same thing. This means that existence itself is based
fundamentally on an assumption.
So that brings us back to the present. If the present isn't
real, and the past is already gone and the future isn't here yet, and
perception is different for everyone . . . how does all of this manage to work?
I have no idea. As Einstein said, "People like us, who believe in physics, know that the distinction
between past, present, and future is only a stubbornly persistent
illusion".[
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