Just as little does the term reasonable as used in law permit a purely intellectualistic view of the process or an _a priori_ standard. The question as to what is reasonable care or a reasonable price is often declared to be a matter not for the court but for the jury to decide, i.e., it is not to be deduced from any settled principle but is a question of what the average thoughtful man, who considers other people as well as himself, would do under the circumstances. A glance at some of the judicial definitions of such phrases as "reasonable care," "reasonable doubt," "reasonable law," as brought together in _Words and Phrases Judicially Defined_, illustrates this view. We get a picture not of any definite standard but of such a process as we have described in our analysis, namely, a process into which the existing social tradition, the mutual adjustments of a changing society and the intelligent consideration of all facts, enter. The courts have variously defined the reasonable (1) as the customary, or ordinary, or legal, or (2) as according with the existing state of knowledge in some special field, or (3) as proceeding on due consideration of all the facts, or (4) as offering sufficient basis for action. For example, (1) reasonable care means "according to the usages, habits, and ordinary risks of the business," (2) "surgeons should keep up with the latest advances in medical science," (3) a reasonable price "is such a price as the jury would under all the circumstances decide to be reasonable." "If, after an impartial comparison and consideration the jury can say candidly they are not satisfied with the defendant's guilt they have a reasonable doubt." Under (4) falls one of various definitions of "beyond reasonable doubt." "The evidence must be such as to produce in the minds of prudent men such certainty that they would act without hesitation in their own most important affairs." There is evidently ground for the statement of one judge that "reasonable" (he was speaking the phrase "reasonable care," but his words would seem to apply to other cases) "cannot be measured by any fixed or inflexible standard." Professor Freund characterizes "reasonable" as "the negation of precision." In the development of judicial interpretation as applied to the Sherman Law the tendency is to hold that the "rule of reason" will regard as forbidden by the statute (_a_) such combinations as have historically been prohibited and (_b_) such as seem to work some definite injury.