iii. The argument is therefore _a fortiori_. The disciple is not above his master, or the servant above his lord. All these subordinate manifestations, though we have in some ways better evidence for them, do but point back to the one supreme manifestation, the Incarnation of our Lord Jesus Christ. We must never forget that behind the alleged miracles of the Gospels we have the absolutely greatest spiritual force that the world has ever known. If our knowledge is as yet very imperfect of the influence of spirit upon matter in general, it is inevitably still more imperfect of this crowning instance of the spirit-world in contact with the material. When we argue upwards from the analogy of the known to the unknown, we must always leave a large margin for the interval between the point at which our common experience, and even higher extraordinary experience, ends, and the point at which this highest of all human experiences begins. Even a strictly scientific method should be conscious of its own limitations; when it has done all that it can do, it should be aware that its ladders are still too short to scale the height that has to be scaled; it must leave room for a venture of faith beyond the furthest horizon of sight. iv. We are not called upon to believe that anything is really contrary to, or in violation of, nature St. Augustine laid down, some fifteen centuries ago: ‘Portentum ergo fit non contra naturam sed contra quam est nota natura’ (_De Civitate Dei_, xxi. 8). We can always exercise an act of faith, that if we really knew what had taken place, and if we really knew the highest laws of the universe, there would not be any contradiction between them. As it is, there is a double margin of error: it is difficult, and in many cases impossible, for us so to translate the language of the distant past into the idiom of the present as to be sure that we can realize what are the facts that we have to deal with; and, even if we had got the facts, we should still have but a very imperfect knowledge of the causes by which they were determined.