List of Rasa'il in The Encyclopedia of The Brethren of Purity - Psychological and Rational Sciences

Psychological and Rational Sciences

1. A Pythagorean explanation of creation, a defense that the universe was indeed created in a way deeply concerned with numbers at some point, and that the decimal system- then a still fairly recent innovative introduction from the Hindus - described the universe.
2. "On the origins of the logos (i.e. intellect considered as a substance and not as a faculty)." Eric van Reijn glosses this epistle as concerning the "Spiritual Creation (according to the Sincere Brethren)."
3. "Man as Macrocosm." Further discussion of a macrocosmic correlation with a microcosm of man's body.
4. "On intellect (as a faculty of the mind), and the object of intellect."
5. "On the revolutions and orbits of the stars. The authors enter at some length on the sidereal period, or Yugas of the Hindus, which became known to the Arabs by a translation of the Siddhanta."
6. Love of the soul for the Creator.
7. Resurrection and immortality of the soul; this risala has especial emphasis on the ascension of the soul, and Davidson says: "In this the whole system laid down in the Cyclopaedia culminates."
8. On motion, and on the Cosmological argument
9. On cause and effect
10. "On the nature of simple and compound bodies." (Or possibly "On definitions and descriptions", which is followed by van Reijn's translation as "Definitions and Classifications"; Davidson: "...treats of Definitions and Determinations, and tries to show the ideal essence of things, simple and compound.")