Saturday, November 21, 2015

A late night conversation about the nature of thought and sensory perception

joão pestana

This article is not something that I intended to write, but it was the fruit of a late dinner conversation among some friends. We started by discussing physics. As a physicist, I was trying to explain how the world fits together according to the most currently accepted theories. As non-physicists, my friends were always "but why?" and "how does that happen?" At a certain point, I had to realize and admit "well... that's what every physicist wants to find out as well!" I want to continue with this topic in a different article on when or if we should ever stop looking for answers. There will always be questions, but answers are harder to come by.

At a certain point, we started discussing vacuum chambers. Innocently enough, they asked me the question "what does it remain when you remove all the air?" For a vacuum chamber on earth, I argued, if it has a window and you can peek inside and see something, then you can be sure that radiation remains. The removal of air it's relatively easy and straightforward, just think vacuum cleaners. You might feel tempted to think that it's impossible, but imagine the following situation.

You're on a submarine going deep and deeper into the depths of the ocean. So long as the structure holds strong, it won't collapse over the immense pressure from the layers of water above. If there was water inside, it would be alright, but there isn't. The same things happens when you remove air from a chamber — all you need is a structure that can withstand the pressure from the layers of air above.

Now for the removal of radiation it's not as easy and that would require complete electromagnetic shielding in all possible wavelengths. If you know what a Faraday cage is, it would be something similar. And that's just to prevent the entry of new radiation, we still need to remove what remains already inside.

Driven by the arrow of conversation, another interesting question — so much I decided to write this article around it — came up. I will not disclosure what it is yet, but will create the context and let the question flow naturally as it did during our evening. As good inquisitors, my friends would not conform with the answers I gave them. I based them on the most accepted theories that are — despite the uncountable experimental evidence — and always will be theories.

Just as we've never seen an apple fall up, we take it for granted that if it falls it falls down towards the center of the Earth. Imagine thought that one day, one apple does fall up towards the sky accelerating away from the center of the Earth. Such a single event would suffice to invalidate many of our theories about how the gears of the universe roll. We can never say that an apple will always fall down. What we do say is that under certain circumstances, given all of our experimental data, we infer that it must fall down.

In the end, the universe is what each one of us perceives through our senses. They allow us to read the energy of electromagnetic radiation in which each different wavelength is associated with a different perceived color. Blue is more energetic than green and green is more energetic than red. Our brains interpret these differences in energy as what we call colors. You and I might perceive colors very differently, but so long as we agree on the names, there'll be no confusion.

Something similar happens for the air pressure differences we interpret as sounds or the specific molecules that trigger our noses to send a signal to the brain which interprets it as either a good or bad smell. Air itself has no proper smell — our brains ignore it — so we can know when particles that are not so common come up.

I see the brain as a processor of information that constantly arrives through our senses — and we do have more than the classic five. We don't have a temperature sensor. Instead, what we actually perceive as cold or hot is the rate at which our bodies lose or gain heat energy. The higher that rate is, the higher is our perceived sense of cold or hot. You can do a simple experiment to prove this at home as follows.
Place a cotton napkin or towel and a spoon in the freezer for an hour. After the time has passed, pick them up. You can even use a thermometer, but you shouldn't need that to believe that they're at the same temperature. Now place each hand to the corresponding object and try to comprehend how you feel that one is colder than the other even though they're at the same temperature.
You've probably figured this out already. The metal in the spoon is a much better heat conductor than cotton which is actually a pretty good heat insulator — the reason we use it to make warm sweaters for the winter! That means that the rate at which your body loses heat to warm up the spoon is much higher that the rate for the cotton. Your body does not want to lose heat and so it gives you a warning that it feels really cold and you should take out your hand immediately.

What if somehow you lose all of the inputs? Imagine that all of your senses — not just the classic five — suddenly stop and you're left in the dark and cannot even feel pain. What happens to your brain? Does it keep working? Now this is the question that came up that night. I tried to argue that it's impossible for a brain to stop working, because there is always some input either as immediate or as a memory. Similarly, it's impossible to conceive a being with a brain — a cognitive processor — which never received a single input. The simple action of waking the brain is an input!

The problem here is that we've created an unnatural concept — that of absolute temperature. This is nothing more that the total energy a given group of particles has at a very specific moment in time. What would be more natural, as far as our body is concerned, would be the rate of change in temperature — how fast does the group of particles lose energy. They're moving fast, but slowing down.

I'll try to make my argument clearer by using an analogy with a Turing machine — that is, a computer. Imagine a processor without memory and accessories. That is much like a brain which never learned a single thing and has received no information from senses. Does it work? Unless you power it up, it doesn't, but powering it up is sending an electric signal (for a digital computer, that is). That constitutes information being entered and the processor might do something if it has any given set of instructions to perform when it powers up.

Our brains are hardwired to perform basic life supporting activities which need not to be learned. We have an innate ability to breathe and pump blood through our cardiovascular system. Everything else about the world around us must be learned through sensory information. We do need that first input — that kick off — nevertheless. If an input never happens, then nothing will work.

Even if we could build a loop that just goes on forever and somehow was built already performing that loop — that is, without an initial start input — there must be an equivalent information within the system that somehow says "go on." My point is this: without senses, nothing works and the coming alive is in itself an input. It may be an endless senseless loop, but it does need that startup instruction or something equivalent. If there exists a set of instructions that never gets that initial input, they're dead — an inanimate object no different from random clumps of matter. I think I finally understand what René Descartes really meant when he said cogito ergo sum — I think, therefore I am.

This was my conclusion from that very interesting late night conversation. These are my thoughts and the theory I've constructed in my head describing how the world I perceive through my senses works. What we all agree upon might be considered fact, but what we don't agree on might be called eccentric or mental illness. Who's to say what's correct? Our senses elude us all of the time and the concepts we create like absolute temperature add to that confusion.