Science may be designated as the search for the understanding of phenomena apprehended by one or more of the senses in terms of theoretically postulated entities and the interrelationships between them in such a manner that the apprehended phenomena may be deducible from them along with others for which it was not postulated and with respect to which its truth and falsity, or rather fecundity or sterility, could be judged. This continuous interplay between the theoretically postulated and the sensuously apprehended, initially in terms of that which is first sought to be understood but more essentially in terms of that which has not yet been apprehended but which can be apprehended if the theoretical postulation is true, is the heart of the scientific enterprise as we have come to practice it today. The theoretical postulation thus links the past with the future, and thus makes the seeking for knowledge connected in an essential manner with what can only be called its relation to the future.