I think also that an experiment is the human attempt to make sense
out of the chaotic world:
the method is you assume chaos, H0 and then disprove it..
so you don't need controls because the experiment can be run to
prove maybe that the equation for velocity is valid..
(validation experiment).. (ie you can disprove the null hypothesis,
chaos by showing that somehthing always occurs)..
I had an argument with a collegue: I said that B may not cause
disease because there was no proof. They said that B did cause
disease because there was no proof against it. Basically I think
I'm write in that you always start with assuming chaos and no relation
between disease and exposure and then you do your experiment..
no controls are needed, i think because sometimes you are just
describing, as Jay pointed out.. like with testing the velocity
equation, or discovering another relationship (equation etc.)
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