Appendix VI. De substantia orbis (inauthentic)

Expositio et questiones in Averrois librum De substantia orbis

(Repert. p. 94; MacClintock, pp. 124-125; Schmugge, p. 130)


Inc. (text) In hoc tractatu intendimus perscrutari de rebus ex quibus componitur corpus celeste … (exp.) Liber iste qui intitulatur De substantia orbis dividitur in proemium et executionem, que incipit ibi : Principium autem. Circa proemium sic procedit … (prol.) Sicut dicit Philosophus secundo Metaphysice, philosophiam veritatis scientiam vocari recte se habet et ratio est quia illa scientia debet merito … (quest.) utrum celum sit compositum ex materia et forma …


This commentary on the treatise of Averroes has been preserved in eight manuscripts and several early editions. I have consulted the edition Venetiis 1552.

The authenticity of the commentary had been questioned before and has now been proved false[1]. Lukasz Tomanek has convincingly argued that it really is the work of Ferrandus Hispanus. In this context it should be noted that among the questions on the Metaphysics attributed to John of Jandun the questions 12-13 of Book XII heavily depend on a collection of questions on the De substantia orbis of Averroes, transmitted in the manuscript Firenze, BN, Conv. Soppr. I.III.6, f. 89ra-108va and probably by Maino de’ Maineri[2].

As indicated by MacClintock, the presentation of the text in the early editions differs from that in the manuscripts; for instance, in Vat. lat. 845 the exposition with interspersed questions is followed by the text of Averroes, whereas in the editions the whole is reorganised: Averroes’s text, with interpolated exposition, is presented first, and the questions come only afterwards (in the edition Venice 1552 the text and exposition cover f. 33ra-50va, the questions f. 50va-63vb). The editions sometimes have additional questions at the end (see MacClintock, p. 125).

John mentioned the De substantia orbis as a work by Averroes in the prologue to his commentary on the Physics: “Considerandum est quod libris prenotatis, in quibus traduntur partes scientie naturalis, annexi sunt quidam alii libelli Aristotelis et Averrois […] liber autem Averrois De substantia orbis annexus est quodammodo libro Celi et mundi quantum ad primum et secundum <libros> et aliqualiter octavo Physicorum”[3]. However, no commentary on this text from his hand has so far been discovered.



[1] In some bibliographical publications, the following reference is erroneously given under the name of John of Jandun: G.J. Etzkorn, John Reading on the Existence and Unicity of God, Efficient and Final Causality, in Franciscan Studies 41 (1981) pp. 120-221 (121-122). In fact, Etzkorn here compares a commentary of Ferrandus Hispanus to a passage of the Sentences commentary by John Reading. And in fact, Ferrandus Hispanus is the real author of this commentary: cf. L. Tomanek, “Natural Reason and God’s Infinite Power: Diversity of Approaches in the Late 13th and 14th Century Commentaries on Averroes’s De substantia orbis”, in Analiza I Egzystencja 54 (2021) pp. 181-215; id., “Fernand of Spain on Prime Matter and Indeterminate Dimensions”, in I. Zavattero (ed.), Issues of Medicine and Metaphysics at the Faculties of Arts between Bologna and Paris, (forthcoming).

[2] Cf. Lambertini & Tabarroni, “Le Questiones super Metaphysicam », p. 53 and n. 20. They quote as their source Ch.J. Ermatinger, “John of Jandun in his Relations with Arts Masters and Theologians”,  in Arts libéraux et Philosophie au Moyen Age, éd. Ch. Wenin, Montréal/Paris 1969 pp. 1173-1184 (1177).

[3] See above Chapter 2 and Appendix I.


Pour fermer la page, cliquez sur l’icône en forme de croix situé en haut à droite.