…the animal perceives sensible things but cannot perceive conceptual realities. For example, the animal sees that which is within the range of its vision but cannot comprehend or conceive that which lies beyond it. Thus it is not possible for the animal to comprehend that the earth has a spherical shape. But man can deduce the unknown from the known and discover hidden realities. So, for example, from observing the inclination of the heavens man infers the curvature of the earth. The Pole Star at ‘Akká, for instance, is at 33 degrees; that is, it is inclined 33 degrees above the horizon. When one goes towards the North Pole, the Pole Star rises one degree above the horizon for every degree of distance travelled; that is, the inclination of the Pole Star will reach 34 degrees, then 40, 50, 60, and 70 degrees. When one reaches the North Pole, the inclination of the Pole Star will be 90 degrees and the star will be seen at the zenith, that is, directly overhead.
Now, the Pole Star is a sensible reality, and so too is its ascension, that is, the fact that the closer one goes to the Pole, the higher the Pole Star rises. And from these two known realities an unknown reality is discovered, namely, that the heavens are inclined, meaning that the sky above the horizon at each latitude is different from that at another latitude. Man comprehends this relation and reasons from it a previously unknown thing, namely, the curvature of the earth. But this comprehension is impossible for the animal. It is likewise impossible for the animal to comprehend that the sun is the centre and that the earth revolves around it. The animal is a prisoner of the senses and is circumscribed by them: It cannot comprehend anything that lies beyond the reach or control of the senses, even though it excels man in the outward powers and senses. It is therefore clearly established that man is endowed with a power of discovery that distinguishes him from the animal, and this power is none but the human spirit.
- ‘Abdu’l-Baha (Table talks in Akka, authenticated by ‘Abdu’l-Baha; ‘Some Answered Questions’ – 2014 revised translation by the Baha’i World Centre)
