In pursuing these considerations about the universe, we arrived at things which, in ordinary language, are usually called "occult." In connexion with this, these remarks ensued: "I am, of course, far from trying to trace out a connexion between the four-dimensionality that you establish, Professor, and the four-dimensionality of certain spiritistic pseudo-philosophers, yet it suggests itself to me that in such occult circles efforts will be made to derive advantage from the fact that the same word is used in both cases. This is more than a conjecture, indeed, for there are no misgivings among the ignorant, and so we actually find the name Einstein quoted in connexion with mediumistic experiments that are flavoured with four-dimensionality." "It will not be expected of me," said Einstein, "to enter into discussion with ignoramuses and misinterpreted. Discarding them, then, let us confine ourselves to a brief consideration of the conception 'occult,' as this has played a part in serious science. The chief example of this in history is gravitation. Huyghens and Leibniz refused to accept gravitation, for, so they said, according to Newton's view, it is an action at a distance and hence belongs to the realm of the occult. Like everything occult, it contradicts the causal order in Nature. We must not regard Huyghens' and Leibniz's contradiction as being due to lack of perspicacity; rather, they objected on grounds which, as investigators, they had every right to uphold. For, as far as our everyday experience is concerned, every mutual influence of things in Nature occurs only by direct contact, as by pressure or impact, or by chemical action, as when a flame is lit. The fact that sound and light apparently form exceptions is not usually felt as a contradiction to the postulate of contact. The case of a magnet appears much more striking because its effect asserts itself as a direct manifestation of force. I must mention that when I, as a child, made my first acquaintance with a compass--and this was before I had ever seen a magnet--it created a sensation in me, which I consider to have been a dominant factor in my life up to the very present. There is, indeed, a fundamental difference between pressure and impact on the one hand, and what we hear and see on the other, even in everyday experience. In the case of light and sound, something must be 'happening' continually, if the effect is to occur and continue...." "Yet another difference seems to enter here," I interposed. "Is it possible to give a full explanation of gravitation by using only the conceptions pressure and impact? Perhaps 'pressure at a distance' would not have seemed to contemporaries of Newton as unintelligible as a 'tension or pull at a distance.' It seems to me that it is particularly difficult to imagine a pull or an attraction towards a distant object."