Barbara Reynolds (1914-2015), Dante: The Poet, the Political Thinker, the Man
(Emeryville: Shoemaker Hoard, 2006), pp. 86-87, with notes on p. 431:
He has observed an evil disposition of the soul attended by three terrible
kinds of sickness of the mind. The first of these is a boastfulness that leads
people to believe that they know everything and to affirm as certain things
that are not. Cicero condemns such people in the first book of his De Officiis
(‘On Duties’), as does St Thomas Aquinas in Contra Gentiles (‘Against the
[T]here are many who by their natural dispositions are so presumptuous as to
believe that they can gauge everything by their intellect, believing everything
true that seems to them true, and false everything that does not.15
Such people never attain to learning, believing they are already sufficiently
instructed; they never ask questions, they never listen, they never desire to be
questioned, and if they are, they reply before the question is concluded and
their answer is wrong.
The second sickness he has observed is caused by a natural dejection of
the mind, which leads people to deny the possibility that anything can be
known, by themselves or by others. They never enquire or reason or heed
what others say. Such people, Aristotle said, were not qualified to be students
of moral philosophy, for they live in ignorance like beasts and despair of all
The third sickness is a kind of levity or superficiality of mind which leads
people to pass all bounds in their reasoning, leaping to a conclusion before
they have framed a syllogism, flying off to another conclusion, believing
they are arguing most subtly when they do not start from any principle.
With those who deny first principles, as Aristotle said, it is useless to argue.
Among them are many uneducated people who do not know their A B C
and yet would dispute about geometry, astrology and physics.16
15. St Thomas’s words are: Totam Naturam divinam se reputant suo intellectu posse metiri
(‘They consider that all Nature can be measured by their intellect’).
16. There is a delightful glimpse of such a person in E.M. Forster’s short story, ‘Other
Kingdom’: ‘“Surely” — said Miss Beaumont. She had been learning Latin for not
quite a fortnight, but she would have corrected the Regius Professor.’