Logic and metaphysics
CP: 1.6 Duns Scotus
1.15. Very early in my studies of logic, before I had really been devoting myself to it
more than four or five years, it became quite manifest to me that this science was in a bad
condition, entirely unworthy of the general state of intellectual development of our age;
and in consequence of this, every other branch of philosophy except ethics -- for it was
already clear that psychology was a special science and no part of philosophy -- was in a
similar disgraceful state. About that time -- say the date of Mansel's Prolegomena
Logica†2 -- Logic touched bottom. There was no room for it to become more degraded. It
had been sinking steadily, and relatively to the advance of physical science, by no means
slowly from the time of the revival of learning -- say from the date of the last fall of
Constantinople.†3 One important addition to the subject had been made early in the
eighteenth century, the Doctrine of Chances. But this had not come from the professed
logicians, who knew nothing about it. Whewell, it is true, had been doing some fine work;
but it was not of a fundamental character. De Morgan and Boole had laid the foundations
for modern exact logic, but they can hardly be said to have begun the erection of the
edifice itself. Under these circumstances, I naturally opened the dusty folios of the
scholastic doctors. Thought generally was, of course, in a somewhat low condition under
the Plantagenets. You can appraise it very well by the impression that Dante, Chaucer,
Marco Polo, Froissart, and the great cathedrals make upon us. But [their] logic, relatively
to the general condition of thought, was marvellously exact and critical. They can tell us
nothing concerning methods of reasoning since their own reasoning was puerile; but their
analyses of thought and their discussions of all those questions of logic that almost trench
upon metaphysics are very instructive as well as very good discipline in that subtle kind
of thinking that is required in logic.
1.624. …The metaphysician who adopts a metaphysical reasoning because he is
impressed that it is sound, might just as well, or better, adopt his conclusions directly
because he is impressed that they are true, in the good old style of Descartes and of Plato.
To convince yourself of the extent to which this way of working actually vitiates
philosophy, just look at the dealings of the metaphysicians with Zeno's objections to
motion. They are simply at the mercy of the adroit Italian. For this reason, then, if for no
other, the metaphysician who is not prepared to grapple with all the difficulties of modern
exact logic had better put up his shutters and go out of the trade. Unless he will do one or
the other, I tell him to his conscience that he is not the genuine, honest, earnest, resolute,
energetic, industrious, and accomplished doubter that it is his duty to be.
2.36. Fourthly: Some writers make it the boast of their systems of logic that they rest
upon a philosophical basis; others really use the same method, though they rather keep
the fact in the back-ground, despite the good ring of saying that one's logic is
philosophical. Only, if logic is to be a pavillion on the roof of metaphysics, then
metaphysics cannot conveniently be made an upper story of logic, as Aristotle and Kant,
the two greatest of metaphysical systematizers, would have it to be. To me, it seems that
a metaphysics not founded on the science of logic is of all branches of scientific inquiry
the most shaky and insecure, and altogether unfit for the support of so important a subject
as logic, which is, in its turn, to be used as the support of the exactest sciences in their
deepest and nicest questions.†1
2.84. . . . I call them Categories.†1 Would I could render them to the reader as vivid, as
undeniable, as rational as they are to me. They will become so, if he will give thought
enough to them. They appear in myriad shapes, of which, for the purpose of introducing
the reader to them, I take the first that offers itself. A definition of experience happened,
just now, to flow from my pen. It was a pretty good definition, I think: suppose we set out
from that. Laconically speaking, experience is esse in praeterito. Only, remember, once
more and once for all, that we do not mean what the secret nature of the fact is, but
simply what we think it to be. Some fact there is. All experience compels your
acknowledgment. What, then, is the fact that is present to you? Ask yourself: it is past. A
fact is a fait accompli; its esse is in praeterito. The past compels the present, in some
measure, at least. If you complain to the Past that it is wrong and unreasonable, it laughs.
It does not care a snap of the finger for Reason. Its force is brute force. So then, you are
compelled, brutally compelled, to admit that there is such an element in the world of
experience as brute force.
2.121 . . . . As to Metaphysics, if the theory of logic which is to be developed in this book
has any truth, the position of the two greatest of all metaphysicians, Aristotle and Kant,
will herein be supported by satisfactory proof, that that science can only rest directly
upon the theory of logic. Indeed, it may be said that there has hardly been a
metaphysician of the first rank who has not made logic his stepping-stone to metaphysics.
2.166. . . For a whole generation, ideas that were not Hegelian were looked upon
throughout the German universities with the same utter contempt with which ideas that
are Hegelian are now regarded in those same halls. But one and the same spirit has
always been prevalent there; namely, to settle first what metaphysical ideas are agreeable
to reason, that is, in effect, to the spirit of the day, and to shape the science of logic to fit
those ideas. That method is no less than preposterous. The only rational way would be to
settle first the principles of reasoning, and, that done, to base one's metaphysics upon
those principles. Modern notions of metaphysics are not rationally entitled to any respect,
because they have not been determined in that way, but on the contrary by a purely
accidental circumstance, or by a circumstance which, so far as it can be looked upon as a
reason, is a reason against rather than in favor of modern metaphysics.
2.713. We usually conceive Nature to be perpetually making deductions in Barbara. This
is our natural and anthropomorphic metaphysics.
3. 487. The logical doctrine of this section, must, we may remark, find its application in
metaphysics, if we are to accept the Kantian principle that metaphysical conceptions
mirror those of formal logic.
7. 580. I shall enter into no criticism of the different methods of metaphysical research,
but shall merely say that in the opinion of several great thinkers, the only successful
mode yet lighted upon is that of adopting our logic as our metaphysics.
Aesthetic, Ethics, Logic
1.191. Normative science has three widely separated divisions: i. Esthetics; ii.
Ethics; iii. Logic.
Peirce: CP 1.191 Cross-Ref:††
Esthetics is the science of ideals, or of that which is objectively admirable without
any ulterior reason. I am not well acquainted with this science; but it ought to repose on
phenomenology. Ethics, or the science of right and wrong, must appeal to Esthetics for
aid in determining the summum bonum. It is the theory of self-controlled, or deliberate,
conduct. Logic is the theory of self-controlled, or deliberate, thought; and as such, must
appeal to ethics for its principles. It also depends upon phenomenology and upon
mathematics. All thought being performed by means of signs, logic may be regarded as
the science of the general laws of signs. It has three branches: 1, Speculative Grammar, or
the general theory of the nature and meanings of signs, whether they be icons, indices, or
symbols; 2, Critic, which classifies arguments and determines the validity and degree of
force of each kind; 3, Methodeutic, which studies the methods that ought to be pursued in
the investigation, in the exposition, and in the application of truth. Each division depends
on that which precedes it.