philosopher... I am not a physicist - yet - nor a philosopher, but here I am, little

old me, not only wondering about the nature of time, but also making a first ever Youtube

video about it. My aim is to make you think, to create discussion... And of course, I hope

you enjoy the video!

The answer to what time is may be as simple as "Time is what the ticks of a clock measure"

or "Time is what keeps everything from happening all at once". But let's dig a little bit deeper

and make this video a bit more fun!

Let's start with Newtonian time. Newton's view of reality implied that time was external

and absolute. Newton's time is a kind of container, where events take place in a completely deterministic

way, linearly and independently of the observer.

Then came Einstein. His theory of special relativity, and then general relativity, both

led to the conclusion that time is relative to the observer. Time depends on where you

are and how you move relative to others. There is no such thing as universal time. Space

and time are constrained by c (the velocity of light) in such a way that the "now" of

one observer is not the same as the "now" of another observer. Mass, equally, can also

distort space and time.

Time dilation and length contraction are not just theoretical constructs within an elegant

theory. These effects have been tested again and again without failure; at macroscopic

scales, Einstein's theory has been shown to be a very good model of reality.

Let's talk about time dilation with an example. We have the elementary particles called muons,

which have a half-life of around 1.5 microseconds. That means that if we have, say, 100 muons

in the lab, after 1.5 microsecond has elapsed, we will have, on average, 50 muons left. The

other 50 will have disintegrated. After another 1.5 microsecond, we will have, on average,

25 muons left... And so on.

These particles are produced at the edge of our atmosphere due to incoming cosmic rays

hitting air molecules. They are constantly produced so there is a constant fall of muons

towards the Earth's surface, travelling at nearly the speed of light. What is observed

experimentally is that more muons are detected than one would have expected, when we consider

their average lifetime.

This fact can only be accounted for when we use the model of time and space given by Einstein's

special relativity theory, where time and space are constrained by c, the velocity of

light, and so times and positions are relative to the observer. In this case, from our point

of view, the muon's own time appears dilated. More of them can reach the earth's surface,

from our perspective, because a second of their time lasts longer than a second of our

time.

So we can see that from the very beginning of last century, the concept of absolute time

was shattered, and time was understood as being completely dependent on the observer.

Newton's absolute time is only a good approximation, when speeds are low and when we can effectively

neglect the effects of nearby masses.

Now, let's take a look at the concept of time from a philosophical point of view. We have

what is called the A theory of time and the B theory of time. These were introduced by

the philosopher John McTaggart at the beginning of last century as well.

The A theory of time says that the only "real" time is the present; the past is gone and

the future exists as just a probability distribution, a potentiality of possible things that can

happen. There is no set future - on a kind of imaginary line "laid out there" for us

- just waiting to happen. Therefore, the future is not "real".

On the other hand, the B theory of time says that past, present and future all co-exist,

and are as "real" as each other. The B theory says that the distinction between past, present

and future are just an illusion of consciousness.

One of the consequences drawn by many orthodox physicists as a result of either Newtonian

physics or relativity theory is that determinism is a fact. That the past completely determines

the future, and hence, all what has happened since, say, the big bang, was determined by

the initial conditions, including you and me and our actions, thoughts and feelings.

There is no room for free will, which is seen as just an illusion, when we take this deterministic

point of view.

Hence, it seems that it is the B theory of time, not A, the model of time that most closely

agrees with the classical equations of physics.

So... It appears that common sense agrees with A Theory, but classical physics agrees

with B Theory. Could it be that time is a bit more complicated than what A or B theories

of time suggest? That reality is a mixture of the two ideas? Could it be that a linear

model of time is not a good approximation of reality? We will explore this issue in

a bit when we talk about Quantum Physics.

Now - before going into quantum physics - let's take a little break. How do I personally think

of time? What is my own experience of time?

On a personal level, I intuitively feel that time is not some mysterious external dimension

or construct that flows in the forward direction, that kind of dictates in what order events

can happen, but I feel that it is rather a much much more fundamental concept, even more

so than space.

I see time as a concept that is intricately linked to the individual's perception of change.

I think of time as "the perception of duration, of change and the ordering of events" by a

living entity or, in fact, you could say, by a conscious entity (here I'm defining consciousness

in line with awareness, hence animals and primitive organisms would have their own concept

of time, depending on how they perceive change).

On the other hand, I do not see time as a strict illusion either, nor as a block of

events completely determined beforehand. I see it as a pliable tool which, when used

within this particular universe, it enables our experience of 3D space and the perception

of the ordering of events.

In this way, I often ask myself that, if time can be thought of as the perception of change...

what happens when there is no change and no perception? Imagine you are somehow still

conscious, but confined in a universe where nothing ever happens and you have no perception

of any change whatsoever occurring (this reality would obviously be nothing like our physical

universe).

What are you left with? The first thing that comes to mind is that time does not make sense

in such a universe, it does not exist, unless change can be perceived by some sort of being

or beings that populate it so that some order can be assigned as to what goes first, what

goes after, etc. Maybe time could be thought of as a perpetual "now" under those conditions.

And all these thoughts obviously bring up the idea of universal versus relative or,

we could say, individual time. However, here we are talking of ideas beyond Einstein's

relativity theory. We are not talking about time and space in our physical universe obeying

certain rules, whereby c, the velocity of light, and mass, restrict how space-time behaves...

but in addition to this, we are talking about time being something that is meaningless in

the absence of an entity / a being (or a consciousness, an awareness) who is able to perceive change,

therefore being able to assign a "before" and an "after" to events that occur.

The other idea that I often wonder about, and that I feel is very important too is:

are space and time fundamental? If so, are they equally fundamental? Could it be that

one is more fundamental than the other?

I intuitively see time as more fundamental than space. I can sort of picture a reality,

a state (let's say a state outside of this universe) where space does not exist but time

does, where only patterns of "states" exist and there is a chronological order that can

be perceived between them (this is analogous to, say, my thought space, when I meditate

for instance... and I reach certain states, where there is no feeling or perception of

space, but there is definitely a perception or distinction between different states and

a perception of which one preceded which).

So time can be thought of as a fundamental structure that allows perception of order

between changing states or patterns (that is, order as in before and after).

A property can then be added so that there isn't just order between states, but there

is also a rule that regulates the basic fundamental tick between events, beyond which change can

not be perceived. In our physical universe, this fundamental duration could be the Planck

time. I will expand on the concept of the Planck units in other videos.

On the other hand, I cannot imagine the perception of a 3D physical space, existing independently,

without time. The way we perceive physical space is dependent on the time it takes for

light to reach our eyes. Even if we talk about non-visual perception, all other types of

physical senses are constrained by the velocity at which information within space can be transferred

physically to our senses. So any successful perception of 3D physical space is tied to

the existence of time.

This is of course, my own interpretation of time. But what does current science have to

say about this? Well, recent research carried out by a particular quantum gravity research

team, involving quantum universe simulations, seem to indicate that time is fundamental

(not emergent), that it existed before space, and not only that, but their theory says that

time has no beginning nor has it got an end!

(For references, please see the video links at the bottom, in particular, the talks by

Renate Loll, a professor of theoretical physics).

As computer simulations get better and better with time, it will be fascinating to see what

kind of universes can be created and what we can learn about the nature of our reality.

All these concepts are inevitably linked to the debate of whether the world exists out

there, independently, without needing aware or conscious entities to perceive it. It seems

that my particular interpretation of time, as I have discussed so far, does not make

sense unless some sort of consciousness is involved (be it a consciousness perceiving

our universe from within it or from outside of it).

So, is there an objective reality out there when there are no conscious beings to perceive

it? This is a fascinating subject that quantum mechanics brought to the surface within the

context of science, at the beginning of last century; a subject which was by no means new

and which many religions and philosophers had already debated for thousands of years.

But the fact that this can now be studied within physics is very very exciting.

When it comes to consciousness, unfortunately, many physicists cringe when they hear this

word. However, this debate was NOT started as a kind of new-age idea, but rather, it

started within the context of experimental science (for example, when discussing the

possible interpretations of the double-slit experiment results).

It seems to me, that it is partly due to some new-age ideas that flourished later on, which

use quantum mechanics as a kind of platform to support their theories about reality, that

today many scientists feel uncomfortable when having to consider consciousness as having

a fundamental role in the way the physical universe works (let me clarify, this is independently

of the validity of these new-age ideas! I personally have no problem with any kind of

ideas, as I try not to have any prejudices or pre-conceptions). The important thing to

remember is that these ideas were initially brought to the surface by many of the eminent

scientists who were at the forefront of quantum mechanics at the time.

Einstein, Bohr, Schrodinger, Heisenberg, Wigner, Bohm, Wheeler... The list goes on. These are

not new-age quacks (a word that pseudo-skeptics seem to over use these days, in my opinion)

but the very brilliant minds who laid the foundations of quantum mechanics.

Most of these scientists didn't just shut up and calculate (a very famous quote by Feynman)

but they discussed the philosophical, metaphysical and physical interpretations of quantum mechanics.

Consciousness (or mind), the existence of objective reality, the illusion of time...

These were not new age ideas, but very important ideas about reality that originally came from

the bunch of brilliant scientists who created quantum theory.

I find it very unfortunate that many mainstream scientists today seem to want to distance

themselves from any discussions involving consciousness, because they associate it with

new-age, spiritual or religious ideas of the universe. There are too many links with eastern

philosophy or religion for their taste...

Not to mention the incredible difficulty of introducing something as immaterial as consciousness

into a purely materialistic view of the universe. I find this quite sad, because when science

finds something that challenges the current paradigm, and there is enough evidence, in

my opinion, that maybe we are actually missing a very important part of the equation, we

should strive to think outside of the box to explain it, rather than trying to make

it fit into our existing (materialistic) view of the universe.

Ok, so let's go back to the concept of time, and explore how it can be perceived from the

point of view of quantum physics. I will try to be brief here, as I will make plenty more

videos on quantum physics in the future, including all its different interpretations.

Quantum physics provides a view of the microscopic world which is based on probability distributions.

Particles do not seem to be actual physical particles as we think of them, unless they

are observed. In the meantime, they seem to exist in some sort of probability realm, in

a superposition of states that obeys a particular wave equation, that is, Schrodinger's equation.

When a measurement is made - meaning that information is made available and retrieved

in the macroscopic reality regarding some property of the particle - then the wavefunction

is said to collapse.

The otherwise deterministic probability wave, suddenly jumps from a superposition of possible

states to just one. It seems that the observer has a very fundamental role in the "now" moment

when reality is observed, when a measurement is taken. So reality appears to be a deterministic

flow in probability space, until, voila, somebody decides to look, and one particular state

is picked from this probability cloud (seemingly randomly), and then reality takes a definite

form. Both the "now" moment in time and the observer seem to be crucial in the description