Solipsism here they come

I would love to know how otherwise intelligent people can argue as follows: all methods are subject to bias of some type, therefore all methods are equally valid. Another one I don’t get is: If a model is considered useful by a group of people in a workshop then whether it is valid or not is a matter of ideology and of no consequence. I ask these two questions because I am encountering them in a debate at the moment.

The first is an obvious absurdity, there are degrees if bias and their reduction is of considerable importance. A method in which 10,000 people index their own stories has higher objectivity than 20 stories gathered in a workshop where said stories are influenced by the facilitator’s preference (15 minutes on average before they do so in controlled experiments). Inspecting seaweed hung from my back door may on occasion be more accurate than the Met Office computers, but not often!

The second similarly, Ok an invalid model may produce useful output, and a valid model may produce poor output. But that does not justify persisting with a model which is not valid, or failing to engage with a debate as to the validity of said model. Why are people afraid of argument? It can’t be laziness surely, or is it a hostility to science and the very notion of proof?

Both arguments abjure reason, degenerating into relativism at best, solipsism at worst.