Die philosophischen Abhandlungen des al-Kindi (1897) - Page 13

Risalatuhu fi mahiyat al-‘aql wa-l-ibana ‘anhu Letter/Treatise on the essence of the intellect and its exposition; that of the treatise "de somno et uisione": 1

Risala fi ‘illat al-nawm wa-l-ru’ya wa ma yurmaz bihi al-nafs Treatise on the cause of sleep and dream and [about] what the soul signals in it (literally: gives a wink with the eyes).

Second, the list of books translated from Arabic by Gerard of Cremona explicitly mentions a Liber iacob alkindi de sopno Book of Jacob Al-Kindi on sleep (for: somno) et uisione — along with the Liber alkindi de quinque essentiis Book of Al-Kindi on the five essences. 2

Third, the headings of the oldest surviving Latin manuscripts agree perfectly with the Arabic titles. (Compare pp. XV, XXII.)

Fourth, regarding internal evidence, it is undeniable that the essays in question bear all the characteristic marks that we expect from the time and place of their alleged origin.

The situation is more difficult regarding the two remaining treatises.

In the registers of Al-Kindi's works, we find the title: 3

Kitab risalatuhu fi al-aswat al-khamsa The book of his treatise on the five words/sounds, which [states] what it is. Hammer, Literaturgeschichte History of Literature, B. III, p. 243: The book on the essence of reason and its exposition. A duplicate is the abbreviated title no. 216: Kitab risalatuhu fi khabar al-‘aql The book of his treatise on the account of the intellect (Al-Nadīm no. 181, Qifṭī no. 156, I. a. Uṣaibi‘a no. 207). Flügel, p. 31: Treatise on the essence of the "Vorstand" understanding (read: Verstandes intellect/reason). Hammer, p. 248: Treatise on reason. Casiri, p. 356, col. 1: de intellectu.

1) Sulle opere di Ja‘qūb ben Isḥāq al-Kindī p. 14, no. 202 (Fihrist no. 169, Qifṭī no. 143, I. a. Uṣaibi‘a no. 194). Flügel, p. 31 no. 188: Treatise on the cause of sleep and the dream and on that which the soul mysteriously indicates. Hammer, p. 248 no. 172: Treatise on the cause of sleep and dreams. Casiri p. 355 col. 2: De somni et somniorum causa.

2) Boncompagni, Della vita e delle opere di Gherardo Cremonese, Rome, 1851, p. 6.

3) Sulle opere etc. p. 9, no. 33. Fihrist no. 29, Qifṭī no. 23.