Thus it is clear that if there were not in man a power different from any of those of the animals, the latter would be superior to man in inventions and the comprehension of realities. Therefore it is evident that man has a gift which the animal does not possess. Now, the animal perceives sensible things, but does not perceive intellectual realities. For example, that which is within the range of its vision the animal sees, but that which is beyond the range of sight it is not possible for it to perceive, and it cannot imagine it. So it is not possible for the animal to understand that the earth has the form of a globe. But man from known things proves unknown things, and discovers unknown truths. For example, man sees the curve of the horizon, and from this he infers the roundness of the earth. The Pole Star at Akká, for instance, is at 33x, that is to say, it is 33x above the horizon. When a man goes towards the North Pole, the Pole Star rises one degree above the horizon for each degree of distance that he travels, that is to say, the altitude of the Pole Star will be 34x, then 40x, then 50x, then 60x, then 70x. If he reaches the North Pole the altitude of the Pole Star will be 90x or have attained the zenith, that is to say, will be directly overhead. This Pole Star and its ascension are sensible things. The farther one goes towards the Pole, the higher the Pole Star rises; from these two known truths an unknown thing has been discovered, that is, that the horizon is curved: meaning that the horizon of each degree of the earth is a different horizon from that of another degree. Man perceives this, and proves from it an invisible thing which is the roundness of the earth. This it is impossible for the animal to perceive. In the same way it cannot understand that the sun is the center and that the earth revolves around it. The animal is the captive of the senses and bound by them; all that is beyond the senses, the things that they do not control, the animal can never understand; although in the outer senses it is greater than man. Hence it is proved and verified that in man there is a power of discovery by which he is distinguished from the animals, and this is the spirit of man. Praise be to God! man is always turned towards the heights, and his aspiration is lofty; he always desires to reach a greater world than the world in which he is, and to mount to a higher sphere than that in which he is. The love of exaltation is one of the characteristics of man. I am astonished that certain philosophers of America and Europe are content to gradually approach the animal world, and so to go backwards; for the tendency of existence must be towards exaltation. Nevertheless, if you said to one of them, You are an animal—he would be extremely hurt and angry.