Comment by thaumasiotes

> The bitch about scientific studies is you can’t find what you don’t know to look for.

This is only true if you assume that all effects are too small to notice. If you run an experiment on adding fluoride to water, declare an interest in enamel thickness, and then observe that 30% of the experimental group died within six months, you just made a finding that you didn't know you should have been looking for.