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  • Let's say if we have this many of something, we'll call it "one", and represent it

  • with this symbol. If we have this many, we'll call it "two", and use this this symbol.

  • If there's none. If there's a certain amount of something and that amount is

  • none many, we'll call it zero and use this symbol. This many, call it three. Duh duh

  • duh duh duh. If there's this many, we'll call it ten. And we're all out of symbols.

  • So we'll just start reusing symbols. And so on. This is a way, we can represent quantities

  • with words and symbols. And we represent lots of properties with words.

  • Like redness. They can have shapes. Things can be cold. Scattered or patterned. They can

  • be wooden or wet. Even though 2 things are shaped differently

  • and are made of different materials we may still call them by the same name because of

  • other characteristics. Things can have movements or behaviours. And

  • we can have descriptions that only come when we're comparing or looking at multiple things.

  • Any characteristic, property, or concept that we think about something, we always also have

  • a word for it. …I thinkthat might not be right.

  • Try to think of something that exists, in a way that you can't describe with words.

  • If you're not talking... we'll know that idea was wrong.

  • When light bounces off an object, the light can be directed by a lens to form an image.

  • A lens in the eye does this and creates an image at the back of the eye where we have

  • an array of neuron cells that detect the light and send the information on the image to the

  • brain. And it's a similar story for your other sensory cells that pick up other stuff.

  • From there your brain tries to make sense of the signals, classifying concepts and trying

  • to build a model of what it's observing. I don't know how that works exactly. How

  • neurons connecting to neurons becomes conscious concepts like white duck jumping.

  • Should probably ask like a brainologist. But for now, let's say our goal is we want

  • the concepts or pictures that we build in our mind to be the same as the world outside.

  • We want to accurately "recreate" the universe (or at least a part of it), into our brains.

  • We don't want to be wrong. How do we do it?

  • Well, observations are the start. If we want to know what the world is like, looking directly

  • at it, is really going to give us the best idea.

  • But at the same time there's a lot of signals that our sensory cells and brains have trouble

  • with. Like certain wavelengths of light and sound. Things that are too small. Or too far

  • away. Or too fast. It can be hard to see an individual part if there's too much stuff

  • going on in the background. If there's too much noise.

  • We can have trouble processing things even when they're right in front of us. Like

  • a face with the eyes and mouth upside down. Goes from "happy birthday Mr.President"

  • to "my sister and mother are the same person". The haphazard way our brains and senses evolved

  • to be wired didn't give us a perfect accuracy, perception or memory.

  • But we can use tools to detect things we can't detect. Microscopes for things that are too

  • small, telescopes for things that are too far away. A tool that detect bits of radiation and

  • plays a fun noise. And instead of trying to remember and communicate

  • properties by feel, we can have this thing we call a centimeter. Just count how many

  • centimeters are the same length as this other thing. And we can use whatever standard of

  • comparison we need. And we can try to always go slowly and systematically.

  • But some people, after they've had the neurons in a part of their brain die, they may no

  • longer perceive faces. They may not be able recognize their friends and family, celebrities,

  • or themselves. They can still see eyes and noses and mouths, and describe their layout.

  • The signal about the light is still coming in. But the brain no longer classifies this

  • arrangement we call a face. In the end there may be a lot of things like

  • thisuseful classifications about the universe, that all of our brains can't conceptualize.

  • But the point is because those signals coming into the brain from the sensory cells, are

  • the only way information can get into the brain. Observations are the only way of really

  • knowing what the universe is like. But we can also, come to new ideas by playing

  • around with old ones. For example we call this many six, and this

  • many four. But we can also frame them together. Then what do we get? Well we already have

  • a word for that amount, we call that ten. Split it in half, how do we describe that?

  • Make a sort of square array out of it, can we describe that quantity?

  • OK, "five times five equals twenty five", isn't an "observation". It's more a play on our

  • "definitions". Its 'a statement that: according to our naming scheme, five times five, and

  • twenty five, refer to the same thing. Or let's say we notice that a parallelogram

  • always has the same area as a square. If the parallelogram always has the same base length.

  • And height. Then we can look at the squares and play around.

  • Go bushoomp, bushoomp, bushoomp... OK, taking what we knew (about the parallelogram and the square) we can come to a new

  • useful model without having "observed" it first. I don't think this is how they actually

  • found this equation but they could have. We can do something like: if everything that

  • we call a Flaggle is blue. And everything that we call a Beener is a Flaggle. If that's

  • the information that we know, then we should also be able to know that every Beener is

  • blue. Even when they (Flaggle and Beener) are nonsense words, the new ideas we come to make sense. Because

  • it's creating a world in our mind and seeing what we would absolutely have to observe in

  • that world, because of the rules that we set. So if we build our rules and definitions and

  • ideas based on observations, we can form new ideas and models that actually describe and

  • match the real world. OK this is deduction. But we can't always describe the world with

  • this much certainty. For example, if we start rolling this dice

  • and we put it in with our eyes closed or something. There's no way we could ever know, ahead

  • of time, what face will turn up when we stop rolling it. What do we know?

  • There are 6 sides, Only 6 possibilities for what will be turned up. Perfectly cubed, perfectly

  • balanced. (Considering these factors) we don't have any reason to think one of the sides is going to turn up more

  • or less than the others. Let's represent the likelihood of each event

  • occurring as being a certain proportion of all the possibilities. Added together they

  • will equal 100%. In this case we think each one has an equal probability of occurring

  • so they're just one sixth of one hundred percent.

  • So we might say, rolling a 3 has a probability of decimal one six seven. Or of all the things

  • that could happen, rolling a 3 is 16.7% of those possibilities. Or we would expect to

  • see a 3 about one sixth of the time. This is all we can do, we don't know what's

  • going to happen so we describe the possibilities. What are the odds of rolling a total of 3

  • when rolling 2 dice? Each dice has the six possibilities, their outcome is independent

  • of one another and we can get any combination between them. Each combination having an equal

  • probability of occurring. These are all the possible mutually exclusive dice rolls. So,

  • we've got these 2 ways of rolling a 3, of 36 possible rolls. There is a 5.6% chance

  • of rolling a 3. Anyways. We've got observation and deduction

  • to form an idea about the world. And they're good, you know they're pretty good. But

  • this other way we can form an idea, is by guessing. Just imagine the way the world is (with all its possibilities, and perhaps you will understand why guessing is a useful method for forming ideas)

  • Great! Why would we do that? I mean there's a lot of possibilities for

  • things that could be in this mystery box, only one of those possibilities actually is.

  • So why don't we just look? (If we just open and look) we can verify the thing thats in there, and falsify all

  • the other possibilities. It's because sometimes it's useful not to wait for an observation.

  • Hear thunder? The last time we heard thunder it rained. (We then guess:) maybe thunder always comes before

  • rain and it's going to rain. We better put away any horse meat we don't want to get

  • wet. We just saw Frank eat these mushrooms, and

  • now he's bleeding out the eyes. (So we guess:) these mushrooms must cause bleeding out the eyes. Let's

  • stay away from them. We do it because seems faster and safer. Our

  • guesses aren't always accurate, in fact you could say they're often not accurate.

  • For example the idea that: the stars and the sun circle the Earth, while the earth remained

  • stationary (AKA the Geocentric Model). Sure it looks like they're swirling around us and it doesn't feel like we're

  • "moving". But at the time I think a lot of people were very opposed to other ways of modelling

  • the system. Or the idea that you can sweat out toxins

  • through your sweat. I don't know the observation that led to this idea, maybe that you smell

  • after eating certain foods. But it doesn't matter the substance, cyanide, sugar or water,

  • you can take a certain amount and it's not going to hurt you. It's when you take too

  • much that it starts to cause damage. If we define "toxin" as a substance that hurts

  • you then, "toxin" isn't a class of chemical. A toxin is any substance you have too much

  • of. So "detoxification" would be sort of the recognition when there's too much of something

  • happen to leak out with the sweat, but unlike urine and stool, sweat doesn't have a lot (of these certain substances)

  • in it. It's almost entirely water. And there's no specializing cells at the skin "sorting

  • chemical" or making things easier to excrete (bodily wastes through the skin). Skin cells function mostly as a barrier.

  • How about the idea that there's this God named Thor behind those loud lights in the

  • sky? So scary. We better sacrifice another horse.

  • Frank? Frank eats everything he sees. It may very well have been something else he ate

  • when we weren't watching. OK, guessing is fine, It's us wondering

  • about the world. It's not the problem. The problem is assuming that we know (the truth). Not recognizing

  • that we're guessing. We'll often take the first idea that pops into our head and

  • treat it as though it were true. Or treat an idea as true because someone told it to

  • us. We all tend to do it. We all have trouble saying "I don't know". Me, I'm no

  • exception. I'm pretty sure I'm wrong more than I'm right. I'm probably wrong

  • in this video. But let's see what we can do.

  • Let's call a guess or hypothetical idea about the world: a hypothesis. It will either

  • match the world outside, or not match the world outside.

  • For us to know whether an idea is true, for us to verify it, we have to observe it directly

  • out there. Turn the made up idea into an observation. For us to know that it's false, to falsify

  • it, we have to distinctly see the real world being inconsistent with the hypothesis.

  • But just because we can imagine something, doesn't mean we can see it. Some ideas are

  • unverifiable. For example, the idea that: "every time

  • we drop this pen, it will fall". It's falsifiable, if we see the pen float or go

  • up or something, just one time. We'll see that no, the pen doesn't always fall. And

  • the hypothesis is wrong. But it's not verifiable. That is there's

  • nothing we can see that will let us know that this idea is true. Even if every time we've

  • ever seen the pen dropped, it fell. The hypothesis wasn't "every time we've seen it",

  • the hypothesis was "every time". Every time will always include, the next time, in

  • the future where we can't observe it. So this specific idea will never be able to be

  • an observation in our mind. Seems like it's stupid overly strict semantics.

  • But the point of it is we never want to confuse the feeling that we're right, with making

  • the observations to actually know something. If the hypothesis was different. Every time

  • we drop this pen in this room today, it will fall. The boundaries of the idea have been

  • set and we can see within those boundaries. But a universal idea about the way the world

  • is has no boundaries. And we can never see it entirely.

  • But at the same time, the pen falling seems to be very consistent. And we've never seen

  • something else happen. Maybe we treat it as though it were true, since it's so universally

  • predictive. But remembering in the back of our mind, observations are the way that we

  • know stuff. And we can't literally see all of this idea.

  • Along these same lines an idea can be unfalsifiable. For example the idea, a squirrel that looks

  • exactly like this, exists somewhere. Somewhere on Earth let's say. It's verifiable. What

  • would we have to see to know it? Just have to see the squirrel. We'll know it exists.

  • But it's hard to falsify. We would have to see every inch of the planet, simultaneously

  • in case it moves around, and see no squirrel in all those places to be able to have observed

  • the absence of the animal. Which let's say is possible. Although maybe this is a bad

  • example. If we've never seen one, and we've never seen any signs of it. And we know that

  • animals almost never have 2 tails. You know the squirrel is mostly just a made up idea

  • We can talk about the low probability of its existence and ignore the idea until there's

  • some sort of observational basis for itand we probably should. But it's just, this

  • isn't entirely falsifying the idea. We haven't truly observed the squirrel's absence.

  • Unfalsifiable ideas can be tricky. Even if an idea is unverifiable, if it's falsifiable

  • you can at least eliminate stuff as you make observations and the hypotheses that are left,

  • are maybe left because they're true. Maybe. With unfalsifiable ideas we can't eliminate

  • stuff. And the idea can stick around with little to no observational basis.

  • An idea isn't automatically right or automatically wrong just because we can't see it. Saying

  • it's unverifiable or unfalsifiable is about the disconnect between being

  • able to imagine something, and being able to observe it.

  • OK, some ideas are both, unverifiable and unfalsifiable. There's nothing we can see

  • to know that they're true and there's nothing we can see to know that they're

  • false. For example, since your experience of the world is all controlled by your brain,

  • it's possible your brain is really attached by wires to a computer or something and all

  • the reality you perceive is fake. Verifiable? Nope. You could even wake up, in your vat,

  • wires coming out of your nips. But that could still just be a part of the simulation. Falsifiable?

  • Nope. If it's not true, everything would look exactly the same.

  • OK, it's like a hypothesis about a that squirrel we had no observational basis for,

  • except we think the squirrel is also invisible. It's like a hypothesis about a God who has

  • the supreme power who could manipulate the world and our lives. But it's only exerting

  • its will in mysterious ways that are indistinguishable from regular ways.

  • Or a hypothesis that the universe popped into existence 10 seconds ago and the only reason

  • we didn't notice was because all the atoms and light and our neurons and memory and everything

  • came to be in the exact shape and position they are now. It also may have happened a

  • year ago, or 6 thousands years ago. Again, not automatically right or wrong it's

  • just we can't see it entirely. Our bodies may be being harvested for energy, while we're

  • kept subservient within a simulation. But at least there's pie.

  • To summarize so far we're wrong a lotand learning is real hard.

  • OK. Let's say there's this new disease, you get a big lump. But people have been saying

  • that eating carrots can make them smaller. And we want to know if it's true or not

  • true. Basically we've got two incompatible hypothesis

  • and we want to know which one matches the world. You know if we're in a world where

  • carrots do shrink lumps, how would that world look? What observations could we expect to

  • make. The problem with these are they are hard to

  • verify or falsify even on an individual level, because of the noise. Kind of like with Frank.

  • Just because we observed them eating carrots, and then observed some change in their lumps,

  • doesn't mean the carrots are causing it. Could be something else they're eating or

  • something else going on in their life that's causing this.

  • Even comparing them against somebody who didn't eat carrots might not be much more help. Because

  • again we don't know what else is important and if carrots only had a small effect it

  • may be lost among the noise. So what else? While we don't know how important

  • the other factors are. Maybe if we sample lots and lots of people and put them into

  • two different groups, only feeding carrots to one of the groups, maybe all this other

  • stuff will average out? And then if we see a difference in the average lump size between

  • the groups, maybe we can attribute it to the main difference between them. The carrots.

  • Would be nice if we record or survey these other factors so we can check to see if there's

  • a relationship between these other stuff and lump size. And check to see if there's any

  • interactions. You know maybe carrots only shrink lumps when the person also eats broccoli.

  • Or something. Or better yet, have both groups eat the same things, have the same lifestyles

  • and be genetically identical clones so that we can be very sure that any changes we see,

  • are from the carrots. Although that could be really hard.

  • OK, two groups, measure lumps sizes before, measure again after some amount of time, feeding

  • carrots to one group the whole time but not the other. Let's say these are how much

  • each person's lumps have changed in size over the course of the experiment. And these

  • are the average lump size changes of the groups. On average, the carrots eaters lumps shrunk

  • more or grew by less. So carrots shrink the lumps? Carrots can help?

  • MaybeBut it could also be the noise from all the other stuff. Maybe carrots did