Handbook of the History of Logic: - Fordham University Faculty

Port Royal: The Stirrings of Modernity 693
can be seen as a premiss. Given the account of logic advocated in this work,
especially the second discourse where logic was seen as giving rules for all actions
of the mind, it is no surprise that this concern is included in logic. But it is also
the case that dilemma arguments which have faulty premisses can mask that fact
by having the same form as sound arguments. It is important to remember that
Arnauld and Nicole see the whole purpose of an argument as a process of showing
the truth of the conclusion, and so in some sense starting with the conclusion as
a problem. Right reasoning involves a clear progression from clearer premises to
the problematic conclusion. In the case of the fallacious dilemmas and the other
fallacies discussed in chapters 19 and 20 of the third part, there is a pattern of
reasoning that gives the picture of a correct argument, but does not succeed.
The section on fallacies reviews the standard fallacies mostly taken from Aristotle’s
Sophistical Refutations: the ignoratio elenchi or proving something other
than what was in question; petition de principe, or supposing for true what is in
question; non causa pro causa or taking for a cause what isn’t a cause; imperfect
enumeration, which here is not so much a hasty generalization, but a failure to consider
options; the fallacy of accident; composition and division; the fallacy of taking
something affirmed conditionally to something affirmed unconditionally; and fallacies
of ambiguity. A brief remark is then made about incomplete or defective
inductions, postponing that discussion to the section on method. The discussion
of these fallacies is clear and quite lively, but not especially innovative. 27 In many
of their examples, Arnauld and Nicole use the discussion to accuse Aristotle of
committing several of the fallacies he himself talks about.
The discussion of these traditional fallacies is supplemented by a section on
fallacies committed in ordinary life and discourse. These are divided into sophisms
of self-love, and sophism arising from the objects themselves. The section on
sophisms of self-love, which contains some of the more entertaining examples in the
Logic, focuses on reasons other than the truth for which one may hold something.
The opening remarks of this section is similar to much later discussions of what is
sometimes called the fallacy of subjectivism. 28 Arnauld and Nicole have in mind
such arguments as the following:
I am from such and such a country, therefore I ought to believe that a
certain saint preached the Gospel there. (262)
I love him, therefore he is the most able man in the world: I hate him,
therefore he is worthless. (263)
27 For a further discussion of these fallacies, see [Woods, 2000, 36–38]. Woods calls this first
group “scientific sophisms” because of a remark Arnauld and Nicole make at the beginning of
the next chapter contrasting sophisms of ordinary life and discourse to those involving matters
of science (260).
28 See for example, the discussion in Kelley, The Art of Reasoning, which treats subjectivism as
a fallacy [Kelley, 1998, 126–127]. Kelley’s analysis of the pattern of reasoning as I believe/want p
to be true therefore p is true. Compare this with the passage in the Logic (263), where discussing
the “sophisms and illusions of the heart”, Arnauld and Nicole say these consist in transporting
our passions to the objects of our passions and judging them as we want or desire them to be.