by Jochen Szangolies

The only thing worse than a good argument contrary to a conviction you hold is a bad argument in its favor. Overcoming a good argument can strengthen your position, while failing to may prompt you to reevaluate it. In either case, you’ve learned something—if perhaps at the expense of a cherished belief.

But with a bad argument, you’re put in an awkward situation. Since you agree with its conclusion, to the extent that you’re interested in spreading belief in this position, engaging it would not seem to be in your best interest. On the other hand, such arguments always carry the necessary raw materials for the construction of future strawmen within them: bundled together, they only need to then be knocked down with great aplomb to try and dissuade belief in the conclusion they purport to further. Hence, I call such arguments ‘straw arguments’.

Take the case of Ernst Haeckel’s supposed ‘biogenetic law’, which posits that the creation of the individual retraces the evolutionary history of the entire species—‘ontogeny recapitulates phylogeny’. Thus, that evolutionary history is manifest in the developmental stages of an individual history, giving direct evidence (of a sort) of this history. The only trouble is, it’s wrong; individual stages of embryonic development do not resemble adult stages of phylogenetic ancestors. Read more »