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 think … that 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

this… useful 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 it… and 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