2. STL: G. de Ockham, Summa Logicae, eds. P. Boehner, G. Gál & S. Brown (Opera Philosophica I: St. Bonaventure, 1974). EL: "The Elementarium Logicae of Ockham," ed. E. Buytaert, Franciscan Studies, 25 (1965), 151-276 and 26 (1966), 66-173. TLM: "Tractatus Logicae Minor of Ockham," ed. E. Buytaert, Franciscan Studies, 24 (1964), 34-100.
4. For example, Pseudo-Scotus defined validity in this way: "A consequence is a hypothetical sentence composed of an antecedent and a consequent, connected by a conditional or inferential connective, which means that it is impossible that, when the antecedent and the consequent are formed simultaneously, the antecedent is true and the consequent false. And then, if it is as this connective says, the consequence is valid; and if not, then the consequence is invalid." Ioannis Duns Scott Opera Omnia, ed. L. Wadding (Paris, 1891), II, 104-5.
7. William of Sherwood, Introductiones in Logicam, ed. M. Grabmann, Sitzungsberichte der Bayerischen Akademie des Wissenschaften, Philosophische Historische Klasse, Jahrgang 1937, Heft 10; Roger Bacon, Sumule Dialectices, ed. R. Steele (Oxford, 1940); Walter Burleigh, De Puritate Artis Logicae Tractatus Longior, ed. P. Boehner (St. Bonaventure, 1955).
9. We can see this transition as similar to that which gave rise to the notion of objective being. In the theory of universale, 'obiective' occurred first as an adverb, but was later reified into an adjective in the phrase 'esse obiectivum.' (See S. Read, "The Objective Being of Ockham's Ficta," Philosophical Quarterly, 27 ). In supposition theory, 'disiunctive' became 'disiunctivum.'
10. Others writing at the same time in the transitional way are John Buridan, Tractatus de Suppositionibus, ed. M. E. Reina, Rivista critica di storia della filosofia, 12 (1957); Pseudo-Campsall, Logica, ed. E. A. Synan, in Nine Medieval Thinkers, ed. J. R. O'Donnell (Toronto, 1955).
11. Paul of Venice, op. cit. (see note 8), p. 94, for example, wrote: "Mobile confused and distributive supposition is the signification of a general term under which it is permissible to make a descent to all its singulars conjunctively with an appropriate middle and conversely with the same middle. For from 'This animal runs and this animal runs and so on for singulars, and these are all the animals' it follows that every animal runs. And the converse inference is valid with the same minor, which is called a singular constantia, as here: every animal runs and these are all the animals; therefore this animal runs and so on for singulars."
13. Any doubts of Russell's sort that one needs a clause saying that these are all the instances were shared by some of the mediaevals; their solution was the constantia mentioned in the earlier quotation from Paul of Venice (see note 11).
15. STL I, 33: p. 95. That Ockham's account of signification was intended as a theory of meaning is shown firstly by Burleigh's reaction (see below) and by such texts of Ockham's as STL I, 3: ll.20-1. where we read: "whatever is signified by an expression can be expressed equally by any synonym."