William Osler Quote

Surrounded by people who demand certainty, — and not philosopher enough to agree with Locke that "Probability supplies the defect of our knowledge and guides us when that fails, and is always conversant about things of which we have no certainty," the practitioner too often gets into a habit of mind which resents the thought that opinion, not full knowledge, must be his stay and prop. There is no discredit, though there is at times much discomfort, in this everlasting perhaps with which we have to preface so much connected with the practice of our art. It is, as I said, inherent in the subject.

On the Educational Value of the Medical Society (1903)