Science Borealis

Science Borealis
Science Borealis

Tuesday, 29 April 2014

Being Philosophical, Doctor ?

I finally made it.
After 6 years in the works I finally graduated and am now a Doctor of Philosophy.
And what better way to celebrate than being a bit (or maybe more than a bit) philosophical about science.

As a chemist, quantum mechanics is a fundamental building block, and as such Schrödinger's name comes up quite often. But many people who did not study quantum mechanics have still heard the name Schrödinger thanks to a thought experiment which includes a box, radioactive material, a bit of poison and one unsuspecting cat. This humble feline became to be known as Schrödinger's cat.
The idea behind the thought experiment is to explain how quantum mechanics works. I won't go into the thought process in depth (that can be found here) but rather I want to touch on the bottom line of what it tells us. That is - we need to 'change' our system in order to 'observe' what is happening.
In the experiment, the box is closed and we can't tell what is happening inside. To know the fate of the cat, we need to open the lid, thereby changing our system from a 'closed' box to an 'open' box.
This change may seem subtle to most of us. What's the big deal? I "just" opened the lid. (you might say). But in fact, the key point I wish to convey is that the reality of the cat changes once we become part of the system. The cat's probabilistic state (being described by a statistical function of both dead state and living state) is transformed into a single definitive state which is strictly living or (the more unfortunate and bordering animal cruelty) a strictly dead state.

The idea that reality is altered by our presence, or lack of, is not a new concept. Every child starts live accepting reality as only the things which are within their sensory reach. Only at a later state, a child acquires Object permanence which means they know things exists even if they cannot be seen/heard/felt/etc. This means that before reaching this development stage, we accept the fact (and sometimes are not happy about it which makes us cry) that things cease to exist once they are walking out of the room.

Now lets take it one step forward (or backwards, depending on your perspective).

What is the sound of a tree falling in the woods when no one is around?

This is a very old question , for which most people would just assume that the falling tree would sound the same whether there is someone to hear it or not. But is it so? (caution: going on a philosophical rant again)
Let us break down our system. What is sound? a disturbance in the air, propagating in space from its source until it reaches the ear drum. So if that is the case, when there is no ear drum around, all we are left with is a disturbance. It can potentially transform into sound if an ear drum was available, but without one, it is merely a potential sound. 
But, you might say, I can put a microphone and record the sound. So there you go. Sound exists even without the ear being around. However, a microphone is just a "middle-man". The microphone doesn't know its sound. The microphone senses the disturbance and translates it into electricity, storing it temporarily. Only when the recording is played through a speaker, does the electrical information (or magnetic if you want to be nostalgic and use audio cassettes) is transformed into a new air disturbance which reaches the ear. So in effect, the microphone only enables you to store the existence of the disturbance, only to be reenacted at a later time, and most likely in a different place.
The bottom line - no ear to hear - no sound - merely disturbance.

This is parallel to the cat story. Isn't it? Our presence in the system is required to "observe" the existence of a phenomena.

How about vision? Clearly light exist without us being around to see it. Right?

Not so sure.

Let me start by asking a question similar to that of the tree, but this time using vision.

What is the colour of a red chair in dark room?

Did you say without a moment to pause "of course its still red"?
How do you know? What is 'red' anyways?

This is a good point to note that this whole blog has been floating in my mind for the past few months ever since I considered applying for the Flame Challenge, whose current question is "What is Color?" (note the American spelling. Yes, this is an American initiative which I think is absolutely fascinating). When I started looking into what is colour, my first point of reference was that of my chemist training - colour is a wavelength of electromagnetic radiation. 
But electromagnetic radiation doesn't know its red, green, blue or pink. Its just an oscillating field (two fields for that matter, an electric field and a magnetic field). So where does the colour come from? In order to understand colour, we need to consider the entire system.
We have a light source which emits electromagnetic radiation. That radiation hits objects, which then interact with the radiation. The two obvious options for interactions are: absorbing and reflecting (there are more, but lets keep it simple). So, some radiation is absorbed, and will never be seen again. Some is reflected, and if chance would have it, and our eyes are not too far away, then the reflected radiation will hit our eyes. Once inside our eyes, the electromagnetic radiation stimulated our visual nerve system which sends a signals to the brain, which interprets them as colours.

Let me sum it up with less words so the message is clear - Colour is all in our heads!
Same as sound (where the disturbance hits our ear drum, sending signals to the brain which are interpreted as sound), vision and colour is the INTERPRETATION of our brain.

If that is the case, the answer is clear. If our brain is not around, then colour cannot exist.
If we are not there to "observe", if we are outside the system, then we are only left with a 'potential' colour, or a 'potential' sound.

What does that mean? Does that mean that colour is not "real"?
As for the question of "what is real?", I'll leave that for you to think about.

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