Franklin, list, on your other questions,
You wrote,
[CP 8.]232. Or, what is usually the best way, he may turn to the
consideration of the hypothesis, study it thoroughly and deduce
miscellaneous observable consequences, and then return to the
phenomena to find how nearly these consequences agree with the
actual facts.
[CP 8.]233. This is not essentially different from induction.
Only it is most usually an induction from instances which are
not discrete and numerable. I now call it Qualitative Induction.
It is this which I used to confound with the second line of
procedure, or at least not to distinguish it sharply.
[....]
[Franklin] So my difficulty is with paragraph 233. When he says
"[t]his is not essentially different from induction," I'm not sure
what 'this' he means.I would think that it refers to the subject of
paragraph 232, but paragraph 232 looks to me as though it simply
describes ideal scientific method--abduce a hypothesis, deduce its
consequences, and then induce the consequents and compare whether
the consequents induced conform to the consequents expected to
follow from the antecedents. [....]
[End quote]
In 233, I think Peirce is referring simply to the last clause in 232:
"then return to the phenomena to find how nearly these consequences
agree with the actual facts".
You go on to ask,
I don't understand why the instances are not usually discrete and
numerable, and I do not understand why this is qualitative
induction. Why is this restricted to qualitative induction, and why
are the instances not usually discrete and numerable? If you could
enlighten me here about how I'm misinterpreting the passage, I would
be thankful.
[End quote]
I'm not too clear on it myself. Qualitative induction involves
evidentiary weighting. In a discussion crude, quantitative, and
qualitative inductions, Peirce says:
1905, CP 2.759. The remaining kind of induction, which I shall call
_/Qualitative Induction/_, is of more general utility than either of
the others, while it is intermediate between them, alike in respect
to security and to the scientific value of its conclusions. In both
these respects it is well separated from each of the other kinds. It
consists of those inductions which are neither founded upon
experience in one mass, as Crude Induction is, nor upon a collection
of numerable instances of equal evidential values, but upon a stream
of experience in which the relative evidential values of different
parts of it have to be estimated according to our sense of the
impressions they make upon us.
[.... End quote]
It makes more sense to me to say that Qualitative Induction is based on
instances that are not discrete, numerable, and of equal evidential
value, than to say that it is based on instances that are not discrete
and numerable. Maybe, in the letter to Carus, Peirce accidentally
omitted the part about "equal evidential value"? My expertise on
Peirce's views on induction is not strong.
You wrote:
In general, I find Peirce much more focused on understanding
abduction from the standpoint of methodeutic in his later work (I
have read some literature which makes just this point), and wonder
how he could have given a fuller treatment of abduction from the
standpoint of critical logic once he changed his views about how
abduction and induction differ. What is the place of abduction in
the theory of information, if not the induction of characters? I
suspect that getting clearer about this will also help in getting
clearer about induction.
[End quote]
If you mean Peirce's theory of information (comprehension × extension),
Peirce said in 1902 that he had previously made the syllogistic forms
and the doctrine of comprehension and extension more fundamental than
they really are for understanding abductive inference.
http://www.commens.org/dictionary/entry/quote-minute-logic-chapter-i-intended-characters-treatise
. Maybe he changed his mind again later, I don't know. He eventually
says that the pragmatic maxim provides the necessary and sufficient rule
for abductive inference, to the extent that it needs rules at all.
Besides that, at the level of critique of arguments (the 'critical
level') he discusses plausibility, instinctual simplicity, naturalness.
https://sites.google.com/site/cspmem/terms#simple and
http://www.commens.org/dictionary/term/plausibility . He sees
methodeutical considerations as completing the justification of
particular abductive inferences - not as explanations _/per se/_, but as
explanations _/worth testing/_ - whereas deductive and inductive
inferences are fully justified at the critical level prior to
methodeutical considerations, in Peirce's view. There seems more to say
at a general level about abductive inference in methodeutic, i.e., in
the study of inquiry and its interplay of the modes of inference. In
some sort of counterpoint, if I recall correctly, somebody said that
Peirce sees the main philosophical study of deductive inference as being
in stechiotic rather than in critique of arguments. Peirce tends to say
that deductive inference gets no real help from philosophy anyway,
except when the topic is probability, which he regards as a
philosophical idea. (Also, in CP 7.525, Peirce sees logic as helping
mathematicians on things like the definition of continuity).
I can't help thinking that abductive inference relies on both experience
and instinct in the sense of inborn talent, and that whatever
not-strictly-instinctual procedures it has at the critical level as an
inference tend to be too tentative or context-bound or vague or the
like, to be worth formulating as general rules rather than as moves
worth trying. I suspect that psychology, sociology, and whatnot may
throw some interesting light on abductive inference as actually
practiced at the critical level by _/homo sapiens/_.
Best, Ben
Best, Ben
On 11/1/2015 10:20 AM, Benjamin Udell wrote:
Franklin, list,
I ran into a place where Peirce mentions eight forms of induction
besides two that he had discussed in the past. It's in the Carnegie
Application, though which I had looked the other day but somehow
missed this:
MEMOIR 19
ON ARGUMENTS
4th paragraph in "From Draft A - MS L75.35-39" (pp 35-39)
http://www.iupui.edu/~arisbe/menu/library/bycsp/l75/ver1/l75v1-06.htm#m19
[Begin quote]
Induction is the highest and most typical form of reasoning. In my
essay of 1883, I only recognized two closely allied logical forms
of pure induction, one of which in undoubtedly the highest. I have
since discovered eight other forms which include those almost
exclusively used by reasoners who are not adepts in logic. In
fact, Norman Lockyer is the only writer I have met with who in his
best work, especially his last book, habitually restricts himself
to the highest form. Some of his work, however, as for example,
that on the orientation of temples, is logically poor.
[End quote]
I'll catch up with your other questions later.
Best, Ben
On 10/31/2015 6:04 PM, Franklin Ransom wrote:
Ben, list,
Thank you for your help with my inquiry, Ben.
I appreciate your searching on my behalf for the nine forms of
induction. After thinking about it a bit, I think I must have gotten
the idea of nine forms of induction from the 10-trichotomy
classification of signs into 66 classes. Ten of those signs are
considered "inducent" (as Nathan Houser remarks in his "The Scent of
Truth"), so I suppose that would suggest ten, not nine. Besides
which, it's not clear that each sign class should come with a
distinct form of inference. So, I suppose that's where the idea came
from, and is likely mistaken as far as inferring there being so many
forms of induction. I'll go with the idea that Peirce only ever
identified three--crude, qualitative, and quantitative.
As to the other question:
I had seen 2.102, but partly had forgotten about it while reading
the sections at the end of Vol. 2, and partly it doesn't quite
explain how abduction should now be thought of, in particular it's
contrast with induction and deduction. The quote from the letter to
Carus is interesting in remarking on the point of contrast with
induction, although a bit ambiguous to my mind. After looking over
the other links you gave, I don't see much of anything I didn't
already know, with the exception of the letter to Carus that you
pointed out.
In Vol. 2, the distinction between plausibility, verisimilitude, and
probability are introduced in paragraphs 662 and 663, so I was aware
of this later distinction; I note that there are paragraphs in Vol. 8
as well, easily found by looking for the search term "plausibility".
Although probability is no longer the unifying idea in addressing the
validity of abduction, there does seem (to me, at least) a likeness
between plausibility, verisimilitude, and probability, and thus his
earlier way of thinking about the three inferences with respect to
probability is perhaps not so far off the mark.
The passage from the letter to Carus causes me difficulty; I'm unsure
how to interpret it. Consider an expanded form of the passage, that
includes the intervening paragraphs, from Vol. 8 of CP:
"229. When one contemplates a surprising or otherwise perplexing
state of things (often so perplexing that he cannot definitely state
what the perplexing character is) he may formulate it into a judgment
or many apparently connected judgments; he will often finally strike
out a hypothesis, or problematical judgment, as a mere possibility,
from which he either fully perceives or more or less suspects that
the perplexing phenomenon would be a necessary or quite probable
consequence.
230. That is a retroduction. Now three lines of reasoning are open to
him. First, he may proceed by mathematical or syllogistic reasoning
at once to demonstrate that consequence. That of course will be
deduction.
231. Or, second, he may proceed still further to study the phenomenon
in order to find other features that the hypothesis will explain
(i.e. in the English sense of explain, to deduce the facts from the
hypothesis as its necessary or probable consequences). That will be
to continue reasoning retroductively, i.e., by hypothesis.
232. Or, what is usually the best way, he may turn to the
consideration of the hypothesis, study it thoroughly and deduce
miscellaneous observable consequences, and then return to the
phenomena to find how nearly these consequences agree with the actual
facts.
233. This is not essentially different from induction. Only it is
most usually an induction from instances which are not discrete and
numerable. I now call it Qualitative Induction. It is this which I
used to confound with the second line of procedure, or at least not
to distinguish it sharply.
234. A good account of Quantitative Induction is given in my paper in
Studies in Logic, By Members of the Johns Hopkins University,†14 and
its two rules are there well developed. But what I there call
hypothesis is so far from being that, that it is rather Quantitative
than Qualitative Induction. At any rate, it is treated mostly as
Quantitative. Hypothesis proper is in that paper only touched upon in
the last section."
So my difficulty is with paragraph 233. When he says "[t]his is not
essentially different from induction," I'm not sure what 'this' he
means.I would think that it refers to the subject of paragraph 232,
but paragraph 232 looks to me as though it simply describes ideal
scientific method--abduce a hypothesis, deduce its consequences, and
then induce the consequents and compare whether the consequents
induced conform to the consequents expected to follow from the
antecedents. I don't understand why the instances are not usually
discrete and numerable, and I do not understand why this is
qualitative induction. Why is this restricted to qualitative
induction, and why are the instances not usually discrete and
numerable? If you could enlighten me here about how I'm
misinterpreting the passage, I would be thankful.
In general, I find Peirce much more focused on understanding
abduction from the standpoint of methodeutic in his later work (I
have read some literature which makes just this point), and wonder
how he could have given a fuller treatment of abduction from the
standpoint of critical logic once he changed his views about how
abduction and induction differ. What is the place of abduction in the
theory of information, if not the induction of characters? I suspect
that getting clearer about this will also help in getting clearer
about induction.
-- Franklin
On Fri, Oct 30, 2015 at 12:01 PM, Benjamin Udell wrote:
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