On the General Science of Mathematics is the third of four surviving works out of ten by Iamblichus (c. 245 CE–early 320s) on the Pythagoreans. He thought the Pythagoreans had treated mathematics as essential for drawing the human soul upwards to higher realms described by Plato, and downwards to understand the physical cosmos, the products of arts and crafts and the order required for an ethical life.

His Pythagorean treatises use edited quotation to re-tell the history of philosophy, presenting Plato and Aristotle as passing on the ideas invented by Pythagoras and his early followers. Although his quotations tend to come instead from Plato and later Pythagoreanising Platonists, this re-interpretation had a huge impact on the Neoplatonist commentators in Athens. Iamblichus' cleverness, if not to the same extent his re-interpretation, was appreciated by the commentators in Alexandria.

John Dillon is Emeritus Regius Professor of Greek at Trinity College Dublin, Ireland.

J.O. Urmson was Tutor in Philosophy at Corpus Christi College, University of Oxford, UK, and Henry Waldgrave Stuart Professor of Philosophy, Emeritus, at Stanford University, USA.