=The Association of Causation: Hume’s Attack on Science.= Among the many traditional conceptions upon which Hume turned his critical examination, that of causation occupies the most of his attention. He discusses it both in the _Treatise_ and in the _Enquiry_. He is the first philosopher since Aristotle to give it comprehensive treatment. He saw that all philosophical, theological, and indeed scientific knowledge rests upon this conception of causation. It was accepted without question by the Scholastics of the Middle Ages, the Rationalists of the Renaissance, and the scientists of his own time. If the conception is valid, Hume’s criticism goes for naught; for “by means of that relation we can go beyond the evidence of our memory and senses.” In that case what becomes of Hume’s psychological analysis that all knowledge consists of impressions and ideas? And if Hume’s psychology falls, all his criticism of the spiritual and the material substance falls also. Upon the validity of the concept of cause depend many of the scholastic arguments for the existence of God, whose existence we can demonstrate although He is not an object of sense impression. Imagination can then go on unrestricted; for God is accepted not only as cause, but as first or uncaused cause. Descartes, Leibnitz, and even Berkeley and Locke had accepted the causal argument for the existence of God, although the latter two had pretended to restrict knowledge to sense-perceptions and ideas. Again, the causal concept has been the foundation for the belief in a functioning soul behind the mental and physical activities of a human being; and on the same causal concept man has argued from sensations to their material substrate. All this is unwarranted and unrestricted knowledge because it “goes beyond the memory and senses.” Not only theology, but science itself has gone “beyond the memory and senses.” Hume dares to doubt the certainty of the causal principle even in scientific knowledge. Is there any necessary connection among events so that with certainty we can predict the occurrence of one event if another is given? Is there in nature and history any causal law so binding that every event is a necessary result of what has gone before and a necessary cause of what will come? The question of cause is, therefore, paramount with Hume. If he is successful in impeaching cause as he has been in the case of substance, scientific theory must fall with theological dogma.