Hi, Straggler.
I have just a minor contribution to the sub-thread about common sense hypotheses:
Straggler writes:
As long as the common sense notion is treated as a genuine hypothesis (i.e. something that needs to be tested and verified) and not a fact (as was the case with the example you cite) I still think common sense notions will provide an inevitable and valid starting point for investigation.
I think "common sense" is most effectively used as a
null hypothesis in scientific studies.
For example, the per capita rates of influence of spiders and other arthropod predators on populations of agricultural pests have been recorded in many entomological publications. The "common sense" prediction is that, in a system including multiple predator species, each species would still exhibit the same per capita effect on the prey population.
As it turns out, this isn't the case: individuals in multiple-predator systems often display a
greater per capita rate than individuals in single-predator systems. This is often because individuals are more likely to interact and compete with individuals of their own species than individuals of other species. Thus, competitive interactions are decreased as conspecific (same-species) predators are replaced with heterospecific (different-species) predators.
But, once this was discovered, it seemed so obvious that we thought we should have considered it common sense all along. So, now we have a new "common sense" null hypothesis to use in our next round of studies.
-Bluejay
Darwin loves you.
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