But to meet this mental demand is no part of the business of science. The study of phenomena, their succession and their classification, is the essential work of science. It has no function, and is possessed of no instrument with which to look behind or below the sequence, in quest of some higher relation. The eye and the mind of the experimentalist know only of antecedent and consequent. These fill the whole circle of his research; let him find these, and he has found all. But since a cause is no more a phenomenon, than a thought is a material manifestation, that which fills the whole circumference claimed by science does _not_ fill all the area legitimately held by reason. A prevision of the order, and the methods of the changes of the universe, is the ideal of science. But mind in its entirety refuses to be locked within such limits. It looks deeper than sequences, and farther back than phenomena; it demands, by the very laws of its existence, their cause. A continuity of transformed causes undoubtedly explains a wide, and ever-widening area of sequences. But that cannot annul the demand of reason for causation. It simply drives it farther back, and higher up, and indicates that the modes of action and relation originated by the primal cause are only the more sublimely rhythmic. Count this a lingering survival of ‘mere metaphysics’ who will, it is withal so stalwart, so perennial in our consciousness, amidst all vicissitudes of knowledge and reasoning, that whatever science may do, philosophy must give it audience. The researches of science, then, are physical. The observable, finite contents of space and time are the subjects of its analysis. Existence, not the cause of existence, succession, not the reason of succession, method, not the origin of method, are the subjects of physical research. A primordial cause cannot be the subject of experiment nor the object of demonstration. It must for ever transcend the most delicate physical reaction, the profoundest analysis, and the last link in the keenest logic. Absolute knowledge concerning it can only be the prerogative of itself. But human reason is not only, and wholly, concerned with the brilliant records of physical enquiry: it is conscious of powers within itself that transcend and elude all the processes of physics, and the analyses of mathematics. The activities of the mind are not exhausted, the demands of the mind are not met, the persistent questions of reason are not answered, by all the processes, all the products, and all the possibilities of physical research combined.