Time is that wherein there is opportunity, and opportunity is that wherein there is no great time. Healing is a matter of time, but it is sometimes also a matter of opportunity. However, knowing this, one must attend in medical practice not primarily to plausible theories,The definition shows that in this passage λογισμός is a generalisation, like the πρόληψις of Epicurus, whose language is borrowed. But whereas πρόληψις corresponds to a general term (e. g. man), λογισμός here seems to mean a general proposition (e. g. man is mortal). Later on it means the use of λογισμοί in making συλλογισμοί, that is, deduction. Theory and theorising are the nearest equivalents I can think of. but to experience combined with reason. For a theory is a composite memory of things apprehended with sense-perception. For the sense-perception, coming first in experience and conveying to the intellect the things subjected to it, is clearly imaged, and the intellect, receiving these things many times, noting the occasion, the time and the manner, stores them up in itself and remembers. Now I approve of theorising also if it lays its foundation in incident, and deduces its conclusions in accordance with phenomena. For if theorising lays its foundation in clear fact, it is found to exist in the domain of intellect, which itself receives from other sources each of its impressions. So we must conceive of our nature as being stirred and instructed under compulsion by the great variety of things; and the intellect, as I have said, taking over from nature the impressions, leads us afterwards into truth. But if it begins, not from a clear impression, but from a plausible fiction,I. e., if the general statement from which we deduce conclusions be a plausible but untrue hypothesis. Conclusions drawn from such hypotheses lead to nowhere. it often induces a grievous and troublesome condition. All who so act are lost in a blind alley. Now no harm would be done if bad practitioners received their due wages. But as it is their innocent patients suffer, for whom the violence of their disorder did not appear sufficient without the addition of their physician’s inexperience. I must now pass on to another subject.

But conclusions which are merely verbal cannot bear fruit, only those do which are based on demonstrated fact. For affirmation and talk are deceptive and treacherous. Wherefore one must hold fast to facts in generalisations also,Or, possibly, even from beginning to end. and occupy oneself with facts persistently, if one is to acquire that ready and infallible habit which we call the art of medicine. For so to do will bestow a very great advantage upon sick folk and medical practitioners. Do not hesitate to inquire of laymen, if thereby there seems likely to result any improvement in treatment. For so I think the whole art has been set forth, by observing some part of the final end in each of many particulars, and then combining all into a single whole. So one must pay attention to generalities in incidents, with help and quietness rather than with professions and the excuses that accompany ill-success.