Monday, November 17, 2008

Logical Conclusions

Following up on last week’s post, there is more to say with the “scientific method”. The last step – drawing a conclusion - is the linchpin where you and your experiment will succeed or fail.

Unfortunately, I am not aware of any ironclad method to draw good conclusions. Even Nobel-winning scientists have made boneheaded conclusions. Possible logical failures are immense.

If there is ever a controversy in science, it is because of the conclusions that people have drawn. As I stated last week, drawing a conclusion is where failing humans really stick themselves in the middle of the picture.

I’ve seen a ton of erroneous conclusions over the years, (including my own), but the most common ones that are more difficult to see are these:

1) Reaching one conclusion and stopping. This is especially true if the conclusion was what was desired or predicted.

2) Reaching the conclusion based on a single piece of evidence. Sometimes 1 piece is all you can get, but that is honestly very seldom the case. Additional evidence from different perspectives makes it more unlikely that the conclusion is wrong.

3) Believing that repeatability of the experiment is additional evidence of the conclusion. All that repeatability shows is that the result is repeatable and that someone should be able to reproduce your result. It doesn’t mean that someone else will reproduce your conclusion. You see this in the drug tests on professional athletes. Their initial urine is divided into an A and B sample. If the A tests positive, the same lab, using the same procedure, retests the B sample. Is it ever surprising that the B test comes back positive as well?

Maybe it’s summed up best by Richard Feynman: “The first principle is that you must not fool yourself -- and you are the easiest person to fool.”

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