Empirically

Philosophy is a science, and as such has no articles of faith; accordingly, in it nothing can be assumed as existing except what is either positively given empirically, or demonstrated through indubitable conclusions.

Sex is empirically non-binary.

"A child can't be transgender." "Medically and empirically speaking, that statement is false."

"You don't have PTSD unless you were in a warzone." "Medically and empirically speaking, that statement is false."

Is there a list of permissible chemicals allowed in veterinary vaccines (and their concentrations) or do we have to determine this empirically through safety studies?

I have no idea why this works, but empirically, it works.

We need to test this idea empirically instead of just speculating about it.