235. But in this latter statement we have transgressed the limits of our inquiry, and are content to be driven back. Suffice it to say that these three gigantic mysteries will persistently hover around the illuminated circle, or, to speak more properly, the illuminated sphere of scientific thought, of which duration, extension, and structural complexity may be regarded as the three independent co-ordinates in terms of each of which the process of development goes on simultaneously as the boundary of the sphere is enlarged. Within this sphere we have only that which can be grasped by Physical Science, but we are not therefore to infer that matter and the laws of matter have a reality and a permanence denied to intelligence. It is rather because they are at the bottom of the list—are in fact the simplest and lowest of the three—that they are capable of being most readily grasped by the finite intelligences of the universe. The following words of Professor Stokes, in his presidential address to the British Association at Exeter, occur to us as very clearly embodying this thought:— ‘Admitting to the full as highly probable, though not completely demonstrated, the applicability to living beings of the laws which have been ascertained with reference to dead matter, I feel constrained at the same time to admit the existence of a mysterious _something_ lying beyond, a something _sui generis_, which I regard, not as balancing and suspending the ordinary physical laws, but as working with them and through them to the attainment of a designed end. What this _something_ which we call life may be is a profound mystery.... When from the phenomena of life we pass on to those of mind, we enter a region still more profoundly mysterious. We can readily imagine that we _may_ here be dealing with phenomena altogether transcending those of mere life, in some such way as those of life transcend, as I have endeavoured to infer, those of chemistry and molecular attractions, or as the laws of chemical affinity in their turn transcend those of mere mechanics. Science can be expected to do but little to aid us here, since the instrument of research is itself the object of investigation. It can but enlighten us as to the depths of our ignorance, and lead us to look to a higher aid for that which most nearly concerns our well-being.’ 236. In fine, the physical properties of matter form the alphabet which is put into our hands by God, the study of which will, if properly conducted, enable us more perfectly to read that Great Book which we call the Universe.