purely platonic

From Plato's Divine Dialogs:

" ...that the simplest and purest way of examining things, is to pursue every particular by thought alone, without offering to support our meditation by seeing or backing our reasonings by any other corporal sense."

And the opposite view, from T. H. Huxley, Physiography 1878:

" ...the attempt to convey scientific conceptions without the appeal to observation, which can alone give such conceptions firmness and reality, appears to me to be in direct antagonism to the fundamental principles of scientific education."