Alchemy and its false presumptions must be distinguished from scientific knowledge, such as mathematics, mineralogy, chemistry, zoology, and botany. Proof of this is that the Ancients never spoke of it: Pythagoras has not devoted a treatise to it, Plato and Aristotle never speak of it, and thus neither do the Greek commentators after them. There is not a single word on alchemy in all of Galen’s voluminous works, nor in that of John Philoponus. In the Islamic age al-Jahiz, Hunayn ibn Ishaq, his son Ishaq, his grandson Hunayn, Abu Bishr Matta, and Abu al-Faraj ibn al-Tayyib keep all silent on the subject. The father of this false science would seem to have been Jabir ibn Hayyan who has turned generations of students after him astray. Al-Farabi, the greatest Islamic philosopher, mentions elixirs (al-iksir) in a highly negative way only once. Even Avicenna, in his treatise on alchemy does not give this art a rational basis. Alchemy is guilty of having waylaid generations of scholars.