The next topic in science that we need to
talk about is a theory.
You’ll notice that I don’t have a step
number next to this and this is because a
theory is not step 7 in the scientific method.
A theory is a scientifically accepted principle
is supported by a large body of evidence and
it comes from testing many, many different
hypotheses.
These are much more general ideas and not
every hypothesis leads to a theory.
So, let’s look at a couple of examples:
The Cell Theory – the cell theory is very
simple.
It just says that all living things are made
of cells.
You can imagine many different hypotheses
tests where you could find a new living thing
and examine “is it made of cells?” or
find something that is not living and see
that it’s not made of cells.
The Theory of Evolution by Natural Selection
– that will be one of our next topics.
Again, this is a theory – it is an accepted
principle based on large body of evidence.
We will talk about some of that evidence coming
up.
There is often a lot of confusion around the
word theory and this comes from the fact that
our common use of the word theory and the
scientific meaning of the word theory are
different.
So, when we use the word in common language,
the theory is just a guess.
You might have – “my theory is that the
Giants are going to do well this season in
baseball.”
That’s just a guess, I don’t have any
particular knowledge in baseball other than
being a fan.
That’s something we use in everyday language.
This is really more like a hypothesis, right?
You are making a guess based on your previous
experience or knowledge, but it’s not based
on any data yet.
The scientific meaning of a theory is the
best testable explanation, that’s got a
lot of data behind it.
So one of my pet peeves is when someone says
“Oh, well that’s just a theory...”
Well, something can’t “just” be a theory
because, by definition, if it is a scientific
theory, it has lots of data to support that
particular explanation of what we are seeing
in the natural world.
Another concern people sometimes bring up
about science, or an issue they think of with
science, is that it is not creative – that
you have art and music and that is creative
and science could basically be done by robots
because it doesn’t have any room for creativity.
That’s actually not the case at all.
There’s a lot of creativity in how we make
observations.
Different people can look at a plate of bacteria
or a microscope slide or a group of geese
and see very different things.
So there is a lot of creativity there.
There is creativity in forming hypotheses.
Are there different possible explanations
to something you’re seeing?
Designing experiments – there’s a lot
of creativity in designing experiments and
I think some of the best biologists of the
20th century are the people who figured out
novel ways to answer questions and design
interesting experiments.
And then even interpreting the data
– taking a data set that everyone sees in
one way and looking at it from a different
view –can really be important to moving
science forward.
We also want to remember what the limitations
of science are, and we sort of talked about
this at the very beginning of this lecture.
Science is not absolute proof.
One of the tenants of the scientific method
is that you can support a hypothesis or you
can disprove it, but you cannot absolutely
prove it.
To give you the reason for this, let me give
you a quick example.
Let’s say that I have the hypothesis that
all swans are white.
And I spend the next 50 years writing down
the color of every swan I see, and I see a
million swans and they are all white and I
continue to support my hypothesis.
That’s great.
Then, I’m 99, I get off an airplane in Russia
and I see a black swan.
That one black swan has refuted my hypothesis,
even though I have a million data points that
say swans are white.
So, scientists feel like we can never absolutely
say that we’ve gotten every piece of data.
You will hear scientist say “to the best
of our knowledge,” “to the best of our
understanding,” “the data suggests that
this is what’s happening.”
They are not saying that because they don’t
know what they are doing, they are saying
it because the scientific method says we cannot
absolutely prove things.
The only people that get to prove things are
physicists, and that’s because they have
laws.
Biology, we have theories, lots of data to
support those...
Laws are something you can actually write
mathematical formulas for and we just don’t
have those in biology, so we can’t have
absolute proof.
Anecdotal observations – stories about things
– I saw a bear eat a blueberry once
– that is an interesting observation and
can be the starting point of science, but
it is not the endpoint.
It is not the results or the conclusions of
science.
Data that’s false – could be accidental,
because you measured something wrong.
It can also be manipulated.
There are, scientists are human beings and
some lie and put false information for ego
reasons or monetary gain.
And generally, that is fixed or caught by
the public nature of science.
But data that is false is not science/scientific.
Science is not the truth.
There are people who seem to make science
their religion and that’s not the point
here.
The point again is to understand the natural
world.
So in this class, we will learn a ton about
the different components of life and how they
work but we will not be covering the meaning
of life.
You are going to have to go to your English
and psychology and philosophy classes to learn
that part.
So again, remember, we’re sticking to how
do we explain and understand the natural world
and how do we help solve problems.
And that’s the scientific method.
