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| Author |
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| 25 new of 411 responses total. |
flem
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response 125 of 411:
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Apr 12 21:43 UTC 2002 |
Hmm. Let's try a different statement, say "it is raining". This can be
either true or false, but I can't know which without looking outside. Now,
consider these two statements:
1. "it is raining, because it is raining"
2. "if it is raining, then it is raining."
The first one asserts that if I look outside, I'll find that it is, in
fact, currently raining. Period. The second clause, providing a "proof"
that it is raining, does not affect the truth value of the statement. Looking
outside, I discover that it is not, in fact, raining at the moment. The
counterexample proves that statement 1 is false.
The second one asserts something significantly different. It claims that,
provided it is raining, I'll find that it is raining when I look outside. It
says nothing whatsoever about what I'll see when it's not raining. In
particular, the fact that when I look outside I see that it's not raining is
*not* a counterexample to statement 2. Using truth tables, one can prove
that statement 2 is always true, no matter if it's raining or not.
We have two statements, one of which is false and the other is true. It
follows that you cannot, by any correct logical reasoning process,
reduce the first statement to the second.
Circular reasoning does not reduce to tautology.
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flem
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response 126 of 411:
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Apr 12 21:47 UTC 2002 |
123 and 124 slipped in. just a sec...
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russ
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response 127 of 411:
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Apr 12 22:12 UTC 2002 |
Re #97: A Very Long Time Ago, I heard a Muzak version of Emerson,
Lake and Palmer's "C'est La Vie". I nearly gagged.
What's worse is that my boss objected when I changed the radio station.
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oval
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response 128 of 411:
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Apr 12 22:25 UTC 2002 |
i used to work at pentagram and had to work on a big design campaign promoting
Musak. it's amazing how much money they have. musak is psychological warfare.
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eeyore
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response 129 of 411:
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Apr 12 22:29 UTC 2002 |
Holy shit, it's math with words.
You guys need a life.
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flem
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response 130 of 411:
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Apr 12 22:31 UTC 2002 |
I'm not insulting jp2 because he disagrees with me, I'm doing it because that
seems to be his preferred method of social interaction. What a jerk. :)
We seem to be working our way back towards identifying semantics as the source
of our disagreement. Let's see if we can figure out exactly what it is.
Circular reasoning is a method of argument. It produces "proofs" of
statements. I claim it is a logically invalid method of reasoning
because it produces incorrect proofs. I assume that no correct proof
can be produced of a false statement. Yet, using circular reasoning,
it is possible to produce a proof of *any* statement. Do you agree
that this makes it logically invalid?
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senna
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response 131 of 411:
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Apr 12 22:33 UTC 2002 |
This is a nice discussion.
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oval
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response 132 of 411:
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Apr 12 23:08 UTC 2002 |
i think this discussion is answering its own question.
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eskarina
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response 133 of 411:
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Apr 12 23:43 UTC 2002 |
What is the question?
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gryffyn
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response 134 of 411:
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Apr 13 01:11 UTC 2002 |
Hi, I'm Griffin Rhys, I'm very new here. my Grandma is helping me type this.
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senna
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response 135 of 411:
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Apr 13 01:58 UTC 2002 |
I suspect that "grandma" is doing most of the work. :)
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bru
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response 136 of 411:
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Apr 13 02:14 UTC 2002 |
Hi griffin, nice to see a nearly two week old expanding his horizons.
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tpryan
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response 137 of 411:
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Apr 13 02:23 UTC 2002 |
re 134: You wouldn't be akin to our Salvador Dali Parton, would you?
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brighn
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response 138 of 411:
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Apr 13 02:50 UTC 2002 |
#130> I've already granted that circular reasoning does not, by itself,
constitute a complete logical proof; indeed, any sections of a proof that are
circular are only there for rhetorical convenience. They're not logically
invalid, they're merely vacuous.
Let's look at your examples again:
1. It is raining, because it is raining.
2. If it is raining, then it is raining.
Let me replace as follows:
A. It is raining
B. It is raining
1. A, because B.
2. If B, then A.
1. is one of the two possible states of world based on 2. If it is raining,
then 1 holds. If it is not raining, then 3 holds:
3. Not B, because not A.
That is, 1 and 3 are the logical possibilities of combining 2 with 4:
4. B or not A ( == A or not A == B or not B because A == B )
That is, in all universes, ONE of 5, 6 are true, and 7 is true in all
universes:
5. (1.) It is raining, because it is raining.
6. (3.) It is not raining, because it is not raining.
7. If it is raining, then it is raining.
I'll grant that stating that circular reasoning reduces to tautologies is an
overstatement, but the two concepts ARE related. The prime difference is that
one entails something about the universe for its truth value, and the other
doesn't.
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jp2
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response 139 of 411:
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Apr 13 02:55 UTC 2002 |
This response has been erased.
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jp2
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response 140 of 411:
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Apr 13 03:14 UTC 2002 |
This response has been erased.
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rcurl
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response 141 of 411:
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Apr 13 05:38 UTC 2002 |
Actually, it is not raining *because* it is raining (given that is
is raining). It would be raining because of a complex interaction of
atmospheric effects. Because invokes cause, which is prior concatenation
of circumstances that must occur for the event to occur. In other words,
"because" is a bad choice of a word in all of this. Was it meant to
mean "given that" or "as a result of the prior set of events", or...what?
The light switch example recognizes this, but raises another issue.
The because sentence is a statement about *process*, and the then
statement is a statement about *state*. That is, there is a temporal
motion in because, but a correspondence with then.
So, stuff that in your logic hooka and smoke it.
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share
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response 142 of 411:
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Apr 13 06:59 UTC 2002 |
Hello,
May I talk here?
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pthomas
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response 143 of 411:
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Apr 13 07:13 UTC 2002 |
Some of you people have the notion of logical validity totally wrong.
Circular arguments, and nearly all other fallacious arguments, are totally
logically valid. Logival validity has a very specific definition and most
of the time can be definitively established. One needs to differentiate
between what validity means when dealing with logic and what validity
means in common parlance.
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i
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response 144 of 411:
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Apr 13 13:11 UTC 2002 |
Could the distinguished members of the Circle for Logical Discussion
please remove their discussion to a more exclusive item, freeing up
the first item of the general conference for people to introduce
themselves, etc.?
Hi, i'm Walter, aka i. I live in a really nice Ann Arbor apartment
that's too big for me (and needs cleaning!), do accounting and light
computer administration for a small local web design/consulting/
hosting/etc. firm, volunteer for various local non-profits, am the
most active conference admin (cfadm) here on grex, and enjoy reading
and conversation far to much for my own good. Enigma is my personal
favorite cf. on grex. I drive a 12-year/18?K-mile old car without
any bumper stickers on it.
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storytel
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response 145 of 411:
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Apr 13 13:59 UTC 2002 |
Hi, I'm Elaine and I'm new to Grex. I was introduced to using computers for
direct communication through bbsing back in the late 1980's, the Internet
in 1998 and now I'm studying compucomputer/network communication at Lansing
Community College
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jp2
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response 146 of 411:
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Apr 13 14:22 UTC 2002 |
This response has been erased.
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vidar
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response 147 of 411:
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Apr 13 14:33 UTC 2002 |
Apparently jp2 has taken at least one philosophy class.
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other
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response 148 of 411:
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Apr 13 15:12 UTC 2002 |
I think a clarification is in order: flem is saying that circular
argumants produce proofs which are wrong and are therefore logically
invalid. (#130, para 3)
brighn is saying that circular arguments are logically valid and that
they can be used in correct proofs, though apparently to no iseful end.
(#138, para 1)
We should distinguish between proofs consisting entirely of circularity
and those in which circularity is merely a part (like the appendix is a
human part, if you don't dig too deeply into the analogy). A proof can
be logically valid even if the premise is false. In fact, this is the
core of reductio ad absurdam, in which a statment is shown to BE a false
premise by logically proving on the basis of it that other things which
are universally known to be completely and obviously false are true. 'A
because A' is logically valid: if A is false then A is false; if A is
true, then A is true.
jp2 in, #140, says
1. A because A.
2. If A, then A.
These statements do not reduce to each other, mainly because they
are both in the lowest possible terms. However, they are
logically
interchangable.
This cannot be correct because they do not serve the same logical
purpose. (1) states that A is in fact the case (is TRUE), while (2)
states that A MAY be true (implying also that A may NOT be true). These
statements are not logically consistent.
Semantically, however, these statements may be taken as interchangeable,
because we may include in the evaluation of (1) our own perception of
whether or not A is actually true, and if not, then we can assume the
statement to actually mean "not A because not A." In a logical context,
we are more constrained in our interpretation.
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remmers
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response 149 of 411:
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Apr 13 15:15 UTC 2002 |
Hm, I don't think I've introduced myself yet in this item. If
I have, I'll introduce myself again. After all, people can't be
expected to remember everything they read; reminders are needed
from time to time. :)
I'm John. I teach computer science at Eastern Michigan University,
have been doing online bbs stuff for 18 years, and am a founder and
staff member of Grex. I dabble in creative writing from time to
time; see e.g. the Writing, Poetry, and Enigma conferences. My
current extracurricular obsession is playing ragtime piano music --
Scott Joplin, Joseph Lamb, et al. During the spring and summer
months I travel to various ragtime festivals around the country,
soaking up the music and playing in public, either officially or
at open piano sessions. You can catch samples of my playing at
<URL:http://jremmers.org/midi/>.
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