"The Earth is spherical despite what is popularly believed … the proof is that the Sun is always vertical to a particular spot on Earth."

“Whosoever rises above things of this world, in front of which you kneel is much stronger than you.”

“We know with certainty that never could man have acquired the sciences and arts by himself guided only by his natural abilities and without the benefit of instruction. medicine, the knowledge of the physiological temperaments, the diseases and their causes, in all their numerous varieties, and the invention of adequate treatment and cure of each of them by drugs or preparations, which could never have been actually tried out. For how could anyone test every prescription on every disease since this would take tens of thousands of years and necessitate the examination of every sick person in the world?”

“I have seen men who had studied the sciences, who knew the messages of the Prophets, the recommendations of the wise, and yet who surpassed the most evil men in their worse deeds, and their depravation. This is very frequent, and so I have understood that these two moral attitudes were favours granted or denied by the Most High.”

“There are mobile objects and stationary objects, but there is neither motion nor staticness.”

“Ask questions stubbornly, very proud men who seeing themselves right without knowing anything about the matter. This shows lack of piety, a tendency to ranting, a weak mind, and excessive vanity. If you hear, or read writing , do not react with violence until you have proof that what is expressed is wrong. Do not accept that with the enthusiasm of the credulous man either until being wholly convinced of that. In both situations you blind yourself and drift away from truth… Act like a person who has no preconceived views, one ready to know and accept what is right and reject what is wrong.”

“Sciences are like powerful drugs, which suit the strong and exhaust the weak. Likewise, complex sciences enrich a vigorous mind, and keep it off evil, but exhaust the mediocre mind.”