Induction and Natural Necessity in the Middle Ages

Syllogizing ad probabilem in Pseudo-Scotus

“…I d.3 1.4, we see the use of a meta-principle drawn from the metaphysics of nature to justify induction, namely, the thesis unimpeded free causes yield always the same results (Wolter, 1987: 109). If this account is correct, things appear to have changed with the text we are considering, however, precisely when two texts are considered: our own treatise of Pseudo-Scotus, and also, proximately, John Buridan's Summulae de Dialectica (Psillos, 2015). If a new perspective is generated in these two highly representative texts for later medieval logic, this perspective is closely connected with the view we find in Pseudo-Scotus.…”

“…The account of the inductive syllogism we find in Ps.-Scotus implemented Aristotle's classical theory in at least two ways, adding to Psillos (2015) conclusion: he took with J. Buridan the intellect to play a different role than in theories in the model of the 'generalizing abstraction'. The achievements of the intellect, in inductive reasoning, do not consist solely in abstracting data from the senses, but in the search for counterexamples to test natural principles, the concludenda of the inductive argument.…”

“…Bos, 1991: 83). With Psillos (2015), could say that for him, as well as for J. Buridan, the intellect has a specific role in induction which differs from the one recognized by Aquinas' and Aristotle's. It seems that Ps.-Scotus also took it that the intellect does not reach its target, namely general principles (or immediate premises for further deductions), by "generalizing abstraction".…”

“…This represents an alternative understanding of induction and inductive syllogisms as compared to classical Aristotelian accounts, but it also differs from other approaches to induction in the 14 th century. In doing so, I am drawing attention for a thematic already explored before, mainly by E.P Bos (1993, 1991), and also by S. Psillos (2015), but I will seek a contribution on an underexplored topic so far, namely, the role of the notion of probability in this text regarding the justification of induction in later medieval logic and dialectics. …”

“…If we take an instance of any normal Barbara scheme AaB, BaC, AaC, and switch the role of the placeholder for middle term by the placeholder for one of the extremes, we obtain a syllogism which does not give a "causal reason" as demonstrative syllogisms do. (Psillos, 2015), both of whom…”