If you have a choice between A and B, and can't "prove" (what?) B is better, that doesn't mean you should choose A.

Economists prefer models and policies based on models, based on data.

Of course economic data is usually statistical in nature, so interpretation leaves a pretty wide margin for personal biases to influence model/policy selection, but that doesn't mean economics is not evidence based.

Proving things is only possible withing a model. That's easy. Arguing for and finding the right model is hard.

Most corporations don't pay taxes... it would be simpler to just remove the taxes as a whole and remove incentives around holding onto underutilized and unutilized capital. That would lead to either an expanding economy or payouts to those who then would be paying taxes.