it, this is the kathartikon, reason’s best means of purgation. This skepticism hinders errors
as much as possible, leads man to more inquiry, and is the path to the truth of the matter
(although not all at once and suddenly, of course, but instead slowly and gradually
through more and closer investigation).
The doubt of postponement is thus actually a certain mark of the maturity of
reason and of experience in the truth of cognition.
21. This sceptical doubt, both in regard to reason and the senses, is a malady,
which can never be radically cur’d, but must return upon us every moment, however we
may chace it away, and sometimes may seem entirely free from it. ’Tis impossible upon
any system to defend either our understanding or senses; and we but expose them farther
when we endeavour to justify them in that manner. As the sceptical doubt arises naturally
from a profound and intense reflection on those subjects, it always encreases, the farther
we carry our reflections, whether in opposition or conformity to it. Carelessness and in-
attention alone can afford us any remedy.
24. In common speech the word doubt means any uncertainty, and in this respect
and this sense doubt is either dogmatic or skeptical. The former is a doubt of decision, but
the latter a doubt of retardation, of postponement. From the former certainty arises, but
from the latter closer investigation and inquiry, in order to attain proper and undoubted
certainty of cognition.
In dogmatic doubt we reject all inquiry and do not accept something toward which
we have, or believe ourselves to have, a grounded doubt. We decide, in short, and say: In
this matter there is no question of attaining any certainty. Thus dogmatic doubt regards
very many cognitions as if nothing at all could be established or settled concerning them.
25. (…) Dogmatic doubt consists in nothing but judging that one can never attain
complete certainty with cognition, and that all inquiry, furthermore, is thus always
conducted in vain and for nothing.
Skeptical doubt, on the other hand, consists in being conscious of the uncertainty
with a cognition and thus in being compelled to inquire into it more and more, so that
finally one may nonetheless attain certainty with the help of careful investigations. The
former, then, the dogmatist, rejects certainty completely and altogether. The latter, the
skeptic, however, searches for it little by little. (…) the scepticus constantly inquires, he
examines and investigates, he distrusts everything, but never without a ground. In this he
resembles a judge, who weighs the grounds for something as well as against it, and listens
to the plaintiff as well as the defendant, prior to and before deciding the matter and
passing judgement. He postpones his final judgement quite long before he dares to settle
something fully. These were the ancient and pure attributes of scepticismus and of an
unadulterated skeptic.
26. (…) a touchstone with which to distinguish truth from deception, since
different but equally persuasive metaphysical propositions lead inescapably to
contradictory conclusions, with the result that one proposition inevitably casts doubt on
the other: I had some ideas for a possible reform of this science then, but I wanted my
ideas to mature first before submitting them to my friend’s penetrating scrutiny.
27. (…) it is not thoughts but thinking (nicht Gedanken, sondern denken) which
the understanding ought to learn.
28. The method of instruction, peculiar to philosophy, is zetetic, as some of the
philosophers of antiquity expressed it (from zetein). In other words, the method of
philosophy is the method of enquiry [forschend]. It is only when reason has already
grown more practiced and only in certain areas, that this method becomes dogmatic, that
is to say, decisive [entschieden].