What is science? What is this course about?

Key points: The goal of science is to render our universe understandable -- to discover the underlying principles that govern how things (ultimately everything) behave. It is much more important to understand the concepts and principles than just the facts to a scientist. The reward for gaining this understanding is the ability to predict things in completely new circumstances.

For example:
By studying how objects fall to the ground, Newton was able to develop a theory of gravitation that we can use to guide a trip to the moon, or to Mars, or to anywhere in the Universe.

Consider this more complex example:

Some years ago planetary scientists announced that they had evidence for fossil life on Mars based in part on pictures like this one: (see Biology Daily http://www.biologydaily.com/biology/Nanobacterium)

How do other scientists go about assessing an assertion such as "Life once existed on Mars?"

By examining all of the evidence and arguments and then checking against new data taken for the purpose of testing the assertion (usually called a hypothesis).

In the case of the Mars meteorite, some facts were not in dispute:

  • that the rock came from Mars
  • that the rock contains a certain collection of chemical compounds
  • that the rock is very old
    BUT
  • although the structures seen in the pictures look a lot like Earth bacteria, the Martian structures are ~100-1000x smaller
  • the possibility that the structures and combination of chemical compounds arose through geologic processes could not be ruled out
 marslife.jpg (41266 bytes)

Later, another team of scientists did experiments on making similar structures just by chemical reactions in their lab.
They stated "After one day of reaction, all of the experiments yielded rhombic-shaped crystals of calcite, and rounded calcite grains (20-50 nm across) which looked like nanobacteria." That is, they made structures of the same size and nearly same shape as the Mars "life". (Kirkland et al. 1999, Geology, 27, 347)

So what should we believe?

The essentials of the scientific method:
1) Examine something or observe some process.
2) Develop a hypothesis to explain what is seen.
3) Apply the hypothesis to new data or a new situation and
see if it continues to explain what happens -- better yet,
make a prediction of what should be observed, and then go
make the observation as a test.

Try this with the "life on Mars."

1) A meteorite that can be traced to Mars has curious elongated 'worms'

2) From their similarity to primitive life forms on Earth, the hypothesis is put forward that they are fossilized early Martian life forms

3) It is predicted that similar structures can only be made by life processes, but other scientists succeed in making roughly similar ones chemically

4) Therefore, we should be skeptical about the hypothesis that they are fossilized life.

 

The key to doing "science" is to test ideas against observed facts.

If the facts as they are known at a particular time do not support an idea, then the scientist will reject that idea. As more knowledge is gained and/or more accurate measurements are made, a formerly rejected hypothesis may be resurrected to explain what is seen. This all sounds rather formal, but it is a perfectly normal process we use all the time in other areas of our lives buttonex.jpg (1228 bytes)

In fact, it sounds very reasonable and boringly unemotional. Trust us, scientists are human and the process is often as messy as any other difficult human enterpriselink to an extra topic. We might more honestly restate the above:

"If the facts do not support an idea, then the scientist will try harder to improve the idea to fit the facts. Often he/she succeeds, and then other scientists' ideas will come into question, causing them to redouble efforts to defend their ideas. Although we like to think that this competition is friendly, occasionally it is adversarial and bitter. However, in any case only ideas that survive all the tests scientists can apply are accepted and carried forward as the foundation for new studies."
It is a capital mistake to theorize before one has the data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts.
-- Sir Arthur Conan Doyle
It is also a good rule not to put too much confidence in experimental results until they have been confirmed by theory.
-- Sir Arthur Eddington
First get your facts; then you can distort them at your leisure.
-- Mark Twain

For example, the argument continues among scientists about whether we have really found fossils of tiny bacteria from Mars. See http://www.biologydaily.com/biology/Nanobacterium for more on the controversy.

In view of what we have just discussed, do you think science can be considered a collection of facts that you memorizelink to a key question

The goal of this course is to apply the scientific method to the questions of why we are here, and of how we got to the point of even asking the question!

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Entrance to the Sun Temple, Machu Picchu, from Windows to the Universe, http://www.windows.ucar.edu/

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