So what's a theory, and what's a scientific theory,
and what's the difference between them,
and does it really matter?
Yes.
Yeah, it matters a lot.
It matters a lot.
A theory, defined, is "a contemplative and rational type
of abstract or generalizing thinking or the results
of such thinking."
A lot of people think of theories as points of view.
I personally have a theory the pineapple
is a magical food that can be added to any other food.
And while it might not make that food better,
it will certainly not make that food worse.
But oftentimes, it will really make that food better.
On the other hand, a scientific theory
is "a well-substantiated explanation of some aspect
of the natural world based on a body of facts
that have been repeatedly confirmed through observation
and experimentation."
To be a scientific theory, a theory needs four things--
rigorous scientific testing, prediction and explanation,
consistency, and parsimonious-ity,
parsimonious-ness.
The essence of being parsimonious.
So let's say I have a theory that when
I let go of this ball, it is going to float upwards.
It's my theory.
I can hold that theory.
So when I subject that theory to rigorous scientific testing--
but let's say that my theory was that within the confines
of Earth's atmosphere and with no special exceptions, when
I release this ball, it would fall downwards.
Now, I can repeat my test over and over and over again
and get the same result every time.
Now, I can never prove to you that when I release this ball,
it's not going to fly upwards.
Science never proves anything, only disproves.
But after rigorous scientific testing,
I can start to form a scientific theory.
Now, scientific theories are predictive and explanatory.
I can predict, based on my scientific theory,
that any object I release is going to fall downwards.
I can also use my theory to start explaining phenomena
in the natural world around me.
I can explain why I'm sitting in my chair, not floating.
I can explain why rain falls.
I can explain why any object I drop will fall
and why the moon revolves around the earth
and how the moon creates waves.
I can use it for a lot of other pieces of science.
Now, we hit consistency, and I'm using that to cover two things.
So first of all, my scientific theory
should logically fit into the scientific body
that already exists.
Now, sometimes it doesn't have to match up perfectly.
Sometimes scientific theories will revolutionize
a field, or other times, they'll just
make them a little bit more accurate.
But my falling ball theory fits in with thousands
of years of apples falling from trees, whereas my ball floating
upwards theory, not so much.
The other way I'm using consistency
is for adaptation and modification.
Guys, if we were in space right now,
this ball would be floating, but that doesn't
mean that gravity is wrong.
You can modify the theory of gravity
to explain how in space things still
are affected by gravitational pulls,
but the different distances make the effect different.
And the final thing you should keep in mind when
formulating your scientific theory
is parsimonious-ness which basically, just means
keep it simple.
I can explain my theory by saying that this ball is being
pulled towards the floor, which is being pulled
towards Earth's crust, which is being pulled towards Earth's
core.
But it's just way simpler to say that the ball is being
pulled towards Earth's core.
And so once you've got a theory, you
can start building other bits of science on it.
Now that we know how things fall,
we can try and overcome that.
We can make spaceships, and we can
make planes that can overcome this falling thing.
Or we can use falling to our ability.
We can use weights and levers and all sorts of things.
Scientific theories let us continue
to expand science and explore our world.
There is the question is, if these things are so rigorously
tested and so scientifically valid,
why are they still called theories?
Why don't we just call them scientific facts?
I mean, we're all pretty cool with the idea of gravity
now, right?
Well, it's because of what I said before.
Science can't prove anything.
It explains and tests and ask questions and builds
and explores the world around us, but it doesn't prove.
So as scientists, we state what we believe to be true.
What our experimentation has shown over and over and over
again in the hopes that we can add a little bit to the greater
scientific puzzle and allow other people to build
on the science that we've done and continue to explore
our world in chemical and biological and physical ways,
but we never prove.
And so in what is one of science's few humilities,
we call it a theory.
But let me be clear, true, tested, scientific theories
are as close to scientific fact as we're ever going to get.
There are a lot of theories in this world,
but scientific theories are something special.
Go forth, do science.