(3) Why is Nature as she is and not otherwise? = Why is it that facts constituting Nature have a certain uniformity (order) continuity and unity in spite of changes that take place continuously? (Reason of Nature).
Broadly speaking, I may say that Science (with its various departments called "Sciences") tries to answer the first question what, the question as to facts of Nature. Philosophy tries to answer the second question how, the question as to the explanation of Nature. Religion or Theology (which includes highest Poetry) tries to answer the third and last question why, the question as to the reason of Nature. You may thus clearly remember the respective provinces of Science, Philosophy and Religion by remembering three words What, How and Why. When you read a book which treats of facts or the what of Nature; or of the explanation or the how of her; or of the reason or the why of her; you may be sure it is Science, Philosophy or Religion respectively that you are reading, whatever be the name of the book itself.
I have said that Science, Philosophy or Religion "tries to answer" and not "answers", because the answer of any of them can never be final or immutable. None of them can ever reach finality. As the experience of mankind grows continuously, new facts or new phases of old facts are discovered in the course of time. Just as men have to adapt or adjust themselves to new facts (or to changes in old facts) or else die; so men's Science, Philosophy and Theology have to adjust themselves to new facts or else become empty nothings.[85]
II.
I have often said that I believe Islam to be the best religion because (so far as I know) it accords best with the current ideas of Science. If you accept my view of the respective provinces of Science, Philosophy, and Religion, you can easily comprehend that a Religion like Islam which purports to expound the reason why of Nature must needs correspond with the what (Science) as well as with the how (Philosophy) of Nature. The three great divisions of Human Thought—I mean, Science, Philosophy and Religion—are necessarily connected with one another, as otherwise they cannot make up the whole Universe of Human Thought and cannot satisfy men's craving for complete and consistent knowledge.
III.
The Law of Evolution which I mentioned in the previous Note is but a Theory of Creation, an explanation of how Nature has come to be what she is. New facts which future ages may discover may prove the theory to be either right or wrong. At present it is the best hypothesis—the best guess—because it accords best with known facts. It acts as a guide to knowable facts as well. It has shown that men cannot progress, indeed cannot long survive, if they fail to adapt themselves to the circumstances of their position, if they fail to fit into their environment which surrounds them like an envelope. Ceaseless change is the order of Nature. Continuous adaptation is the law of life. Adaptability is therefore the sine qua non of men's life and existence. The religion which suits them must also have the quality of adaptability. I hold Islam has this quality in an eminent degree and is therefore the most suitable religion.
Please remember that I speak of Islam as taught by the Qur'an itself and not "Muhammadanism" as professed by some so-called followers of the Prophet. You have to interpret the Qur'an[86] quite naturally as any other book or historic document, but not in the way in which some Muhammadans do it with the aid of marvellous fictions and miraculous traditions. Islam has to resist (to use a big word) the anthropomorphic tendency of the human mind, viz., the tendency to view abstract qualities or agencies as persons having a separate existence as individual beings.
IV.
I have said that there is no inherent antagonism between Christianity and Islam if and when the sayings and doings of the founders of each are rightly viewed and understood in a simple and natural manner. Muhammad never ceased saying that he had come to attest and complete the mission of Jesus and his predecessors, who were God's messengers like himself.[87] The greatest and the best rule of human conduct which Jesus laid down was: "Love thy neighbour as thyself".