kind of motivating

why it is what we're doing and why we will be doing it in a particular way. This also holds for physics and for geoscience, whatever kind of natural science we're dealing with; same kind of methods,

same kind of history

so I like this picture- a lot of things are beautiful

and that you might have gotten those moments- I think we all have- where you look up at the sky or something else around you wonder, you know, how can all of this be? Why is it so beautiful and amazing?

One way to address that

and try to get a grip on all these

beauties around us is to kind of, you know, give a scientific description.

or put some elements in place.

and that is more easily said than done. And it's always

fun to realize

put yourself in this situation thousands of years ago. Say you're one of those

greek thinkers, and you lie on your back, and you look at the starry night, and you wonder, what is that light

in the far distance. What is that?

right now we know it's a star. Our sun

is a star, too. We know that.

back in the day, of course, they did not know. How do you actually come to such a conclusion? That is not trivial.

Right now in our lifetime we know so much

we take a lot of knowledge for granted. Knowledge has accumulated over the years.

But this is not trivial stuff. All of this knowledge took time to build up.

So it's fun to realize that sometimes it's actually

not trivial

to come to a certain conclusion.

So these people live in those

ages where not a lot of things were known.

And they were starting to think about

what is matter? I mean, how should we

think about matter? Can we give proper descriptions of matter?

So this person, Thales,

he says everything is made out of water

Okay? So he is trying to understand why do certain materials have certain properties, and his way of thinking about it had to do with, maybe it contains different amounts of water

Maybe water acts in a particular

way in different materials.

Democritus says, "well, I don't think that's the case." He says,

"I think materials are based on an accumulation of

many many many many tiny little particles

altogether

that are, in turn, indivisible ones.

stopped the most fundamental level there is a type of

pull that bring particles together

and they form the material on a larger scale

is the atomistic theory

that we know now is the best way to think about materials. But in those days, they did not know.

So Democritus is actually

a person that lived at a later time

than Thales,

however

Aristotle, you may know him,

was a person that lived at a later time than Democritus and

he did not believe this assertion

of Democritus

he said

he said something...about... (laughter)... the computer stopped.

he says speak the materials are not made out of indivisible particles, but they are composed of different amounts

of fire, earth, water,

air, and aether.

So it's a very different way of thinking about materials.

Now all these things, they can be true, I mean,

how do you know? I mean, at some

level you can say anything you want.

So how are you going to discriminate

between different

world views, if you want.

So how can we be sure that

if we know know Democritus is probably

the person that gave the best description but how do we know that?

Well, it turns out that if you actually start to do experiments and test things

over and over and over again, if you at some point can arrive at conclusions that make more

sense, more sense than other conclusions,

and then at some point you may be able to rule out

some hypotheses and confirm

others.

So basically, you take materials, you start to

look at them very carefully, manipulating them, do experiments on them,

a whole series, and

based on the logical kind of deduction, you can

arrive at certain conclusions.

So this is something people started to do

very early on, but really

they were ramping up

in medieval times

and accumulated

into kind of the method

that we now call the scientific method.

So this is kind of like the early days, and in terms of chemistry those were the alchemists

and they were really fascinated of course by

turning everything in to gold. Everybody wanted to be rich,

and if you're a poor person,

of course what you want is more money

and the way to get that is to have more gold.

If you can turn

dust to gold, then you are golden.

but you have to be able to do that, and so in order to

do that, motivated by this, say, pressure for economic

welfare, you start to experiment, sort of manipulate, and you actually

discover a whole bunch of properties of matter that you have not encountered before.

and here is a person that was also in that tradition

one of the later ones, okay? So this is

almost leaving the medieval times here

and he says

'why don't you just like, forget about

making gold but instead use the

methods that we've been

working with to do something good?"

For instance, finding medicines.

He is a person who was very

motivated by helping other

folks, other people, medically.

he said, 'the best way I can do that is by

actually using these methods like observing, experimenting, trying to understand

how the human body works, and then try to help this person.

This may seem very trivial, but this was not trivial because most

medical practices were based on mystic beliefs that did not necessarily have anything to do with a logical deduction of observations. Where you use the observations.

Okay, so he actually

used observation and

logical deduction

and did something good. For instance, he says

infection comes from outside the body, okay? Which is something that people did not know.

People thought that if you got an infection, it comes from you,

because you did something bad. Now we know it's a little microorganism that attacks you and sits there and causes problems.

He did through observing that, you take those states out of people in situations,

you actually have less infection.

He was still like a person of his time. For instance,

he still believed in bloodletting.

Cleansing through bloodletting. That was something disproven, but this

because the belief was so strong

we still thought it was a good practice.

Okay. So that leads us here

basically we have this method of trying to get closer to, um, I wouldn't say the

truth, necessarily, but to a better description of what matter is.

And so I want to make the distinction here that that method is

very different from

an opinion.

Scientific inquisition is not

coming up with better opinions.

So for instance, if this person says

"that's how it is"

he may say, "it's not."

he will say, "yes it is," he will say, "njet!" Okay? So these people have different opinions, and they will

never agree on anything.

But it's very hard to make sense of this.

Okay, so opinions are great

for a whole bunch of purposes, the driving force within our society, it does a lot of good, but then it comes to

finding the proper descriptions of nature, this is not a good

way to go about it.

Scientific inquisition is very different

and, you know, this is kind of like a very

short explanation of how the method works: you have a

clear observation of an event,

you give a very

proper description

of that event, which is frank.

Which is as frank as you can be.

Not biased

by what you want it to be

okay? This is really the difference between

opinion and scientific inquisition. You have to leave everything that you believe out of your system and just let the observation do its work. This is really hard for people, but that's really important. So,

a detailed description

of the phenomenon by frank observation

try not to be biased, or colored,

in your observation.

Then, you come to the interpretation. For instance,

This is Newton

you all know the example

apple falls, he gives a very detailed description

of what he saw,

the apple was sitting there, it was coming loose,

fell to the ground very close to him,

he gave a very detailed description, and then he says, well I can explain that if i come up

with this formula, of course the story is much longer than that,

but he has a formula and then -- very important,

you take that

interpretation

and you test it again

is this interpretation true under all circumstances?

it means that if an apple falls from this

tree,

is this also true for

another apple from a different tree?

Or from a different object? For instance, if I go and launch it from a building, Does it also obey this law?

If given,

It this law describes the falling of objects

throughout, then

you can give this a certain amount of credit, so to speak, in the sense that

this is a good description

of falling materials.

This is not an opinion. At all.

This is scientific inquisition.

Okay. So this of course is also the method that we

follow in chemistry

so let's say we have a beaker with chemicals, we do an experiment,

something changes.

you provide detailed descriptions of these

changes

of these phenomena

then we come up with an interpretation

For instance, this substance

must be a reducing agent. Okay? That is an interpretation, and with a hypothesis, you have to test it. Okay? We go back

change something,

for instance, say, if this were a reducing agent,

if I put a lot of, you know,

oxidizing agents in there,

the reaction must be different

and so you do that, and indeed if it is different,

then you actually strengthen your hypothesis.

okay, several times, until

you've exhausted all possibilities, and then you can

conclude that this must be an actual description of this

situation here.

again, this is not an opinion.

You cannot just say, 'oh, I think this is a reducing agent. It must be so.' No,

you actually investigate that scientifically.

All right, here's a couple of people,

so after medieval times people started to use that method

consistently

Robert Boyle is one of these people,

and he, through that method, that scientific method,

actually uncovered a lot of different kinds of

laws that are enveloped into chemistry. For instance, the gas law

and the differences between

compounds and mixtures. That was one of Boyle's contributions.

also the preposterous theory of matter

was reaffirmed

he brought back this idea

from Democritus

long forgotten because Aristotle had dominated the way people thought about matter. He said, 'hold on a second

my experiments indicate that

if you assume that

materials are made out of indivisible particles, I can explain all my observations.' Therefore,

this must be

a better description

than the description based on, for instance,

earth, fire,

air,

and aether. Right? So,

based on that,

he could throw out Aristotle's description as

not being a good description

no hard feelings, just not a good description.