The usual heroic story is of Pasteur vs. Pouchet. It is a story in which Pasteur proves that there is no such thing as spontaneous generation of life, an old superstitious belief he finally overcame.

Pasteur was a hired gun who needed to figure out how to prevent life from appearing in wine. If there is spontaneous generation, then that is hopeless. He discovered, and everyone agreed, that if you boil something and then seal it, nothing grows. But there is no air.

The dispute is whether nothing grows because

• air is required for spontaneous generation
• when you let in air, you let in germs

Letting air in without letting in germs is what we now call sterile technique, and it has changed our lives.

How can you test whether a technique is sterile? You try it, and see if anything grows. But that method assumes that there is no spontaneous generation. It was, pretty much, Pasteur's attitude.

On the other side, people knew you could denature things by treating them too harshly. (That is, you can render them unfit to support life.) Therefore, proponents of spontaneous generation could define away "sterile technique" as denaturing.

Science in France was centralized at the time, there were committees appointed to settle scientific questions. The committees in this case were all stacked in Pasteur's favor so much that Pouchet kept withdrawing in protest. The issue was "decided" before the experiments, and in part because the committees thought that evolution required spontaneous generation and they were opposed to evolution.

The Moral Some experiments look completely different when described in the language of one perspective from the way they look when described in the language of another. There is no way of describing experiments that is neutral, and so, depending on what you already believe or want to believe, experiments can seem to show different, even opposite, things.

-- ShaughanLavine - 21 Nov 2005 - 19 Nov 2007