On Aug 8, 10:09 pm, "Rod Speed" gmail.com> wrote:

How is your case stronger? We were talking about an analogy between
some generation of ideas and selection amongst a pluralistic field of
possibilities, Or comparing some activities of the brain with
evolutionary processes.

Or are you saying that you have a stronger case, by logical reasoning,
that you are not using logic whenever you argue.

If so I think that violates common sense;

Universal skepticism is usually stated in one of two ways.

------------------------------------
[1] - Positive Universal Skepticism:

In its positive form it consists
of the doctrine that man
can know nothing.

This belief can be easily dismissed, because anyone who defends it
finds himself immersed in hopeless absurdities.

In asserting that there is no knowledge, the skeptic is asserting a
knowledge claim-which according to his own theory is impossible.

The universal skeptic wishes to
claim truth for a theory that
denies man's ability to arrive
at truth, and this puts the
skeptic in the unenviable
position of uttering
nonsense.

...he cannot even begin to argue for his position, because the
"possibility of knowledge is presupposed in the very possibility of
argument, in the very possibility of having recourse to reasons." [8]
As Francis Parker explains:

There is such a
thing as knowledge.

The assertion of this proposition is necessarily true if there is to
be
any assertion at all, for its contradictory is self-contradictory.

If the assertion
"There is no knowledge"
is true, then it is false

...for that assertion itself purports to be an instance of knowledge.
Thus the only alternative to the recognition of the existence of
knowledge is, as Aristotle said, a return to the vegetative state
where
no assertions whatever can be made.

http://groups.google.com/group/alt.philosophy/msg/b86ea8051203c7f6

Sorry for the snip, but am busy right now. But here are some tools for
establishing your case that the analogy was weak or that you have
formulated counteranalogies which, by the way, is the main way of
refuting analogies. [be back stronger tommorrow, I enjoy pointing your
mistakes]

ARGUMENT BY ANALOGY

A common form of inductive argument is the argument by analogy. This
is an argument in which a conclusion is drawn about a situation based
on similarities of this situation (analogies) to previous situations.
For example, if we predict that a since it is snowing today a certain
employee will be late because in the past when it was snowing the
employee was late, we are making a probabilistic argument based on an
analogy, the occurrence of snow.

An argument of the form:
s and t share the properties Pl,..., Pm.
s has the property Pn.
Therefore, t has the property Pn.

Argument by Analogy (Invalid)
Argument with (typically) the general form x is like y, x is A, y is
A.

Argument by Analogy (Valid)
Argument which also has the valid form x is like y with respect to
(being or not being) A x is A y is A.

An analogy is a comparison that works on more than one level. Argument
by analogy is good argument when the things you are comparing have
relevant characteristics in common. Watch out for analogies that
overlook significant differences between the things compared. To use
analogy successfully, a writer must clearly demonstrate how the
important characteristics in the example are operative in this case
and why these variables apply here. An analogies that simplify cause
and effect are likely to have problems and be fallacious.

VII Analogy

To make an induction based on an analogy is to draw a conclusion about
one thing based on its similarities to another thing. Consider, for
example, the following argument against a hypothetical military action
in the Philippines.

In the 1960's, America was drawn into a war in an Asian country, with
a terrain largely comprised of jungles, against enemies that we could
not recognize and friends that we could not count on. That war began
slowly, by sending a few "advisors" to help survey the situation and
offer military advice, and it became the greatest military disgrace
that our country has ever known. We all know what happened in Vietnam.
Do we really want a repeat performance in the Phillippines?

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Fallacy #3 False Analogy

This argument enumerates the similarities between one event and
another event and argues that these similarities will produce a
similar result. While arguments by analogy tend to be very persuasive,
they can very easily fall into the trap of the false analogy, which is
the major fallacy associated with this kind of reasoning. Both valid
and false analogies compare similar things; false analogies, however,
use hasty generalizations as the grounds for comparison. Consider the
following pair of statements.

A war in the Phillippines would be disastrous. Our soldiers had a
terrible time fighting in the jungles in Vietnam, and the terrain
around Manilla is even worse.

If we decide to attack the Phillippines, we should probably do it in
January. We attacked Iraq in January, and look how well that turned
out.

The first of these statements is a valid analogy in that the
comparison meets the test of inductive validity: it takes an
observation (we had a hard time fighting in the jungles of Vietnam),
makes a generalization (it is hard to fight modern warfare in a jungle
terrain), and then applies it to another instance (we would have a
hard time fighting in the jungles of the Phillippines). The second
statement, on the other hand, is a false analogy because, though it
goes through the same process, the inductive leap it makes (we win
wars because we fight them in January) is a hasty generalization.

################################################

Bad Analogy: claiming that two situations are highly similar, when
they aren't. For example,

"The solar system reminds me of an atom, with planets orbiting the sun
like electrons orbiting the nucleus. We know that electrons can jump
from orbit to orbit; so we must look to ancient records for sightings
of planets jumping from orbit to orbit also."

Or, "Minds, like rivers, can be broad. The broader the river, the
shallower it is. Therefore, the broader the mind, the shallower it
is."

Extended Analogy: the claim that two things, both analogous to a third
thing, are therefore analogous to each other. For example, this
debate:

"I believe it is always wrong to oppose the law by breaking it."

"Such a position is odious: it implies that you would not have
supported Martin Luther King."

"Are you saying that cryptography legislation is as important as the
struggle for Black liberation? How dare you!"

################################################

ARGUMENT BY ANALOGY

Philosophical analogies approximate the form of mathematical
proportions and therefore might appear to be tight deductive systems.
For example, A is to B as C is to D has the same form as 1/2 = 2/4,
but the "numerators" and "denominators" of philosophical analogies are
never mathematically identical. This ultimately makes mathematical
proportions and philosophical analogies quite different. (See the
difference between parallel and analogical arguments below.) It makes
them inductive arguments, an argument that does not lead to necessary
truths. Only deductive arguments give us truths that are true in all
cases and without exceptions, e.g., the truths of logic, math, and
geometry.

In assessing the value of philosophical analogies, we must ask two
questions: Are the things compared similar? and are the things similar
in the particular respect in question? If these two questions can be
answered in the affirmative, then a convincing argument from analogy
probably exists.

In his book Practical Logic, Monroe C. Beardsley contends that there
is no such thing as an argument from analogy. "Analogies illustrate,
and they lead to hypotheses, but thinking in terms of analogy becomes
fallacious when the analogy is used as a reason for a principle" (p.
107). Beardsley does, however, give a good example of an analogy which
is "strong" and which can be used to represent one thing as another.
This is the analogy of a map: "The dots on the map are not very much
like actual cities, and the lines on the map are not all like
mountains or wet like rivers.... But the structure of the map, if it
is a good one, corresponds to the structure of the country it
represents. That is, the shapes of the states are like the shapes on
the map; ...and the relative distances between actual cities are like
the relative distances between the dots on the map" (p. 106). It is
clear that such analogies can be very helpful in clarifying the form
and structure of some arguments, even to the point of discrediting a
specific argument.

Parallels vs. Analogies

A parallel argument: all elements are equal or similar in all
essential particulars;

Or at least identical syntactical elements in corresponding positions.

Analogies have neither of these features.

Mathematical ratios are perfect parallel deductive arguments.

...............................................

Another widely used mode of philosophical argument is analogical
reasoning. Philosophical analogies approximate the form of
mathematical proportions and therefore might appear to be tight
deductive systems. For example, A is to B as C is to D has the same
form as 1/2=2/4, but the "numerators" and "denominators" of
philosophical analogies are never mathematically identical. This
ultimately makes mathematical proportions and philosophical analogies
quite different. It makes then inductive arguments by the definitions
above.

In assessing the value of philosophical analogies, we must ask two
questions: Are the things compared similar? and are the things similar
in the particular respect in question? If these two questions can be
answered in the affirmative, then a convincing argument from analogy
probably exists.

In his book Practical Logic Monroe C. Beardsley contends that there is
no such thing as an argument from analogy. "Analogies illustrate, and
they lead to hypotheses, but thinking in terms of analogy becomes
fallacious when the analogy is used as a reason for a principle" (p.
107).

Beardsley does, however, give a good example of an analogy which is
"strong" and which can be used to represent one thing as another. This
is the analogy of a map: "The dots on the map are not very much like
actual cities, and the lines on the map are not all like mountains or
wet like rivers...But the structure of the map, if it is a good one,
corresponds to the structure of the country it represents. That is,
the shapes of the states are like the shapes on the map;...and the
relative distances between actual cities are like the relative
distances between the dots on the map" (p. 106).

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Analogy and Similarity

As a first step in analysis, we can represent the structure of an
argument by analogy as follows:

1. A and B are similar
2. A has property P
_______________________
3. B has property P

A and B are two things being compared: skill in tennis and the art of
reasoning.

The conclusion is that B has a certain property: the art of reasoning
must be acquired by practice.

The argument is that B has this property because it is similar to A,
which has the property. The art of reasoning must be acquired by
practice because it is similar to tennis in being a skill.

A premise about tennis can yield a conclusion about logic only on the
assumption that tennis and logic are similar.

If two things are similar, they must be similar in some particular
respect--in shape, color, function, or whatever. To put it
differently, two things are similar because they share some property.
So the first task is to identify the respect in which A and B are
similar, to identify the property they have in common. In some cases,
this property is stated explicitly, but in others it isn't.

In the argument about tennis and logic, the property is stated
explicitly: they are both skills.

We'll use the letter S to stand for the property that A and B have in
common, the property that makes them similar. We can reformulate the
first premise in an argument by analogy as follows:

1. A and B have property S
2. A has property P
_____________________________
3. B has property P

We can go on to ask the next--crucial--question. What is the
relationship between S and P? If there is no connection between these
two properties, then the conclusion does not follow.

So the strength of the argument depends on the likelihood of a
connection between the properties involved, and our goal in evaluating
an argument by analogy is to estimate this likelihood.

.......................................

Analysis of Arguments by Analogy

Once we have identified the property that A and B are supposed to have
in common--the property we're labeling S--we can put an argument by
analogy into a standard format. This format includes an inductive step
and a deductive step, and it allows us to evaluate the argument by
using what we have already learned about induction and deduction.
To see how this works, let's continue with the analogy between tennis
and reasoning.

The common property here is that both are skills, and the relevance of
this property is that skills must be learned by practice.

Tennis is a particular instance in which a skill requires practice,
and it serves as inductive evidence for a generalization about all
skills; this generalization is then applied deductively to the case of
reasoning.

The first step in the argument is the inductive one, supporting the
generalization that all skills require practice. This generalization
serves as a premise in the second step, which is deductive, a
categorical syllogism.

That premise expresses the link between skills and practice, and
without this premise, we have no basis for the conclusion.

The other premise says that reasoning is a skill--it states the
property that makes reasoning similar to tennis.

Two items being compared:
Logic and tennis
The respect in which they are similar:
They are both skills

The consequence of the similarity:
Being learned by practice

Inductive Part:

INSTANCE:
Tennis is a skill and tennis is learned by practice.

GENERALIZATION:
Therefore, all skills are learned by practice.

Deductive Part:

1. All skills are learned by practice.
2. Logic is a skill.
3. Therefore, logic is learned by practice.

.................................................

Evaluation of Arguments by Analogy:
Rules for Evaluation

The first rule is to consider the number and variety of the positive
instances. In the case of an analogy where we have only a single
instance, the key question to ask is whether increasing the number or
variety would affect the argument.

In the analogy between reasoning and tennis, tennis is a physical
skill, but the generalization is about all skills: physical, mental,
social, and so forth. So we need to consider whether examples from the
other categories would confirm the generalization.

The second rule is to look for disconfirming instances.

In the analogy between reasoning and tennis, can you find examples of
skills that are not learned by practice? If so, this counts against
the generalization that all skills are learned by practice.

Counteranalogies--in this case, similarities between logic and other
types of skills that are not learned by practice--are one of the most
effective ways of rebutting an argument by analogy.

The third rule is to consider the initial plausibility of a
generalization, the plausibility that there could be a connection
between subject and predicate--in this case, between S and P.

Given everything we know about skills, for example, it is quite
plausible to think that they are acquired by practice.

.......................................

Evaluation of Arguments by Analogy:
Finding the Middle Term

In some cases, it is easy to identify the middle term, especially if
the argument explicitly mentions what A and B have in common.

In many cases, however, the common property is not mentioned
explicitly; there may be more than one common property, and it may not
be clear which ones are relevant to the conclusion.

A useful technique is to construct a table of similarities and
differences. In outline, the table would look like the following:

A B
S1 S1
Similarities S2 S2
S3 S3
Differences D1 D1
D2 D2
____
P P

The two columns represent the properties of A and B. Because the
conclusion of the argument is the claim that B is P, we put P at the
bottom and draw a line above it in the B column to indicate that it is
supposed to follow from information available in the rest of the
table.

S1, S2, S3, and so forth--there could be any number--are similarities
between A and B, properties that they share and that are candidates
for the role of the middle term.

To decide which of them is the middle term, we ask which of them seem
connected to P. If they are all relevant, then the middle term is a
combination: S1 + S2 + S3 . . . Usually, however, we can throw some of
the similarities out as irrelevant to the analogy.

It's a good idea to include any differences (D1, D2, . . .) as well,
because we must consider these when we evaluate the inductive element
in the argument.

Once we have selected the most plausible middle term, and analyzed the
argument accordingly, we need to evaluate the inductive step.

We are supporting a claim about B on the basis of its similarity to A,
so A is the only instance available to support the generalization.
Also, we have seen that a single instance usually does not provide
very much evidence for a general proposition.

In this respect, an argument by analogy is a kind of logical shortcut,
and it is a relatively weak mode of argument. Nevertheless, such
arguments vary a great deal among themselves in their degree of
strength, and we can assess their strength by applying our rules for
evaluating generalizations.

http://www.wwnorton.com/college/phil/logic3/welcome.htm

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An analogy is a similarity or likeness between things in some
circumstances or effects, when the things are otherwise entirely
different. In mathematics, an equation between ratios; as, Napier's
analogies an explaining of something by comparing it point by point
with something else. In biology, similarity in function between parts,
dissimilar in origin and structure: distinguished from homology. In
logic, the inference that certain admitted resemblances imply probable
further similarity. In linguistics, the process by which new or less
familiar words, constructions, or pronunciations conform with the
pattern of older or more familiar (and often unrelated) ones: as,
energize is formed from energy by analogy with apologize from
apology.

Analogy is a sort of similarity. It is, we could say, similarity on a
more definite and more conceptual level. Yet we can express ourselves
al little more accurately. The essential difference between analogy
and the other kinds of similarity lies, it seems to me, in the
intentions of the thinker. Similar objects agree with each other in
some aspect. If you intend to reduce the aspect in which they agree to
definite concepts, you regard those similar objects as analogous. If
you succeed in getting down to clear concepts, you have clarified the
analogy.

Analogical thought is dependent on high-level perception in a very
direct way. When people make analogies, they are perceiving some
aspects of the structures of two situations - the essences of those
situation, in some sense - as identical. These structures, of course,
are a product of the process of high-level perception . . .

Analogical thought further provides one of the clearest illustrations
of the flexible nature of our perceptual abilities. Making an analogy
requires highlighting various different aspects of a situation, and
the aspects that are highlighted are often not the most obvious
features. The perception of a situation can change radically,
depending on the analogy we are making. . .

Furthermore, not only is analogy-making dependent on high-level
perception, but the reverse hods true as well: perception is often
dependent on analogy-making itself. The high-level perception of one
situation in terms of another is ubiquitous in human thought . . . In
the large or the small, such analogical perception - the grasping of
one situation in terms of another - is so common that we tend to
forget that what is going on is, in fact, analogy. Analogy and
perception are tightly bound together.

It is useful to divide analogical thought into two basic components.
First there is the process of situation-perception, which involves
taking the data involved with a given situation, and filtering and
organizing them in various ways to provide an appropriate
representation for a given context. Second, there is the process of
mapping. This involves taking the representations of two situations
and finding appropriate correspondences between components of one
representation with components of the other to produce the match-up
that we call analogy.

Our conceptual networks are intricately structured by analogical and
metaphorical mappings, which play a key role in the synchronic
construction of meaning and in its diachronic evolution. Parts of such
mappings are so entrenched in everyday thought and language that we do
not consciously notice them; other parts strike us as novel and
creative. The term metaphor is often applied to the latter,
highlighting the literary and poetic aspects of the phenomenon. But
the general cognitive principles at work are the same, and they play a
key role in thought and language at all levels . . .

Analogical mapping is so commonplace that we take it for granted. But
it is one of the great mysteries of cognition. Given the richness of
the domains and their complexity, how are the "right" schemas
consistently extracted, elaborated, and applied to further mappings?

The aspects of analogy that are relevant for present purposes, they
include:
domain mapping from a source onto a target;
extraction of an induced schema (of frame)
extension, fluidity, and reanalysis." (p102)

According to the standard lore, the two main modes of inference
corresponding to learning from experience are analogy and induction.
Loosely speaking, analogy (in the inferential sense) is the transfer
of information from one situation to another, similar one, and
induction is the acquisition of general principles from collections of
individual experiences . . .

Introspection and anecdotal evidence suggest analogy as a common form
of reasoning in humans. Tasks involving recognition of structural
similarity between objects, an important component of analogical
reasoning, figure heavily in tests of human intelligence; an early
study of such tests, intellectual ability can be defined as the
ability to reason by analogy from awareness of relations between
experienced characters. . . .

. . . What the definition amounts to is that analogical inference
takes place when further similarities between situations are inferred
from known similarities.

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Flow Chart for Analyzing Arguments by Analogy: Part IIIa
http://tinyurl.com/cffk

These rules are implemented in a working computer program: NETMET. You
can download NETMET
http://ww2.wpunj.edu/cohss/Philosophy/FACULTY/esteinha/netmet.zip

http://www.dimensionalthinking.net/analogy.html