horses and mules. Eventually, an inductive procedure will indicate that all animals of a certain kind are long-lived whenever their bodies do not contain a significant quantity of bile: Syllogism I: 43 Longevity holds of humans, horses etc., Being a K holds of humans, horses etc.Longevity holds of all Ks
Syllogism II:Absence of bile holds of humans, horses etc., Being a K holds of humans, horses etc.
Absence of bile holds of all KsRelying on this result, the inquirer proceeds to an inference that could be described as an 'inverted demonstration', where the explanatory term is not the middle, but the major extreme: 44
Syllogism III:Longevity holds of all Ks, Being bileless holds of all Ks Longevity holds of all bileless animalsIn fact, the co-occurrence of longevity and absence of bile made Aristotle believe that, in certain animals, the latter is the explanation of the former. 45 Thus, in Syllogism III, the explanans appears in the conclusion while the explanandum occurs in the major premisean inference a modern reader could classify as abductive. However, while the so-called 'inferences to the best explanation' are non-deductive, Aristotle believes that, if the induction that precedes it is sufficiently comprehensive, we can obtain a deduction to the best explanation. Lines 68 b 24-27 refer back to APr II 22, 68 a 21-25, where Aristotle has shown that if two terms A and B hold of all C, and C also holds of all B, then A necessarily holds of all B. Therefore, if the induction shows us that all and only the members of the relevant kind are bilelessand perhaps this is what Aristotle means by the enigmatic phrase 'the entire universal' in APo II 19 ( , 100 a 6-7) -, we are warranted to convert the previous minor premise and obtain 'a deduction from induction'concluding that all bileless animals are long-lived:
Syllogism IV:Longevity holds of all Ks, Being a K holds of all bileless animals Longevity holds of all bileless animals 43 I am calling Syllogism I, II, and III 'syllogisms' just for the sake of exposition. Technically speaking, these arguments are not Aristotelian syllogisms, since Aristotle uses the term ' ' only for valid arguments in syllogistic form. 44 The terms called 'middle' and 'extreme' in T4 do not match the roles they play in the argument discussed in the passage, which means that these expressions are used as rigid designators of the middle term and the extremes of a demonstrative syllogism. See Ross (1949, pp. 484-485). 45 PA IV 2, 676 a 30-677 b 10.'learning by demonstration'? Let me suggest the following solution. The term 'demonstration' is ambiguous: in one sense of the term, 'demonstration' is the name of a reasoning (a proof-search procedure, one could say) in which a scientist tries to identify propositions (already known to be the same thing-x as explained by y. As a result of her learning, she now has scientific knowledge of x, which she previously knew only non-scientifically' (Bronstein 2014, p. 14). 56 Lesher (2010, pp. 148-156). 57 '[...] akribeiam, quae non solam certitudinem...