"Hitherto we have regarded physical laws only from the point of view of _Causality_, inasmuch as we always start from a condition known at a definite cross-section of time, that is, by taking a time-section of phenomena in the universe, as, for example, a section corresponding to the present moment. But, I believe," he added, with earnest emphasis, "that the laws of Nature, the processes of Nature, exhibit a much higher degree of uniformity of connexion than is contained in our time-causality! This possibility suggests itself to me particularly as the result of certain reflections concerning Planck's Quantum Theory. The following may be conceived: What belongs to a definite cross-section of time may in itself be entirely devoid of structure, that is, it might contain everything that is physically conceivable, even such things (so I understood him to say) as, in our ordinary physical thought, we consider impossible of realization, for example, electrons of arbitrary size, and having an arbitrary charge, iron of any specific gravity, etc. By our causality we have adjusted our thought to a lower order of structural limitations than seems realized in Nature. Real Nature is much more limited than our laws imply. To use an allegory, if we regard Nature as a poem, we are like children who discover the rhyme but not the prosody and the rhythm." I interpret this as meaning that children do not suspect the restrictions to which the form of the poem is subject, and just as little do we, with our causality, divine the restrictions which Nature imposes on occurrences and conditions even when we regard them as governed by the natural laws we have found. Thus a leading problem of science in the future will be to discover the restrictions of Nature as compared with the apparent causality implied in physical laws. We have in this an example of the transcendental perspectives that are opened up when we accompany Einstein on one of his excursions of thought. In this case it is actually a question of ultimate things, of a region of discovery of which we cannot yet form a conception, and it appears doubtful whether the problems latent in it are to be treated by making investigations into physical nature, or whether they are to be allotted to speculative philosophy. In the first place, Einstein's remark seems to aim at nothing less than a revision of the conception of causality. However much has been done to purify this conception and to make it clear, we have here, perhaps, a new possibility of refining it by making a synthesis of scientific and abstract philosophical views. We shall just touch very lightly and superficially on the possibility of a synthesis giving us an avenue to truth. Whoever has heard these words of Einstein, feels the need of getting on to firm ground to rescue himself out of the turmoil of ideas into which he has been plunged.