PLAUSIBILITY CONCEPTS
by F Richard Singer III
edition date 11/2006
website: www.conceptualstudy.org email: richardsinger3@sbcglobal.net
Abstract: This
paper is a reorganization of concepts formulated in my book A Personal Approach to Conceptual
Philosophy. Note a proposition is conceptualized as a statement that
clearly proposes information, at least for the purposes at hand. In Section 0,
a personal plausibility attitude is initially conceptualized as a relation
between a person and a proposition. The key tool for this involves the use of
numerical intervals as a way to indicate compactly both a level of personal
plausibility and an extent of personal uncertainty. The concept of a personal
plausibility is then casually extended to also include statements that are
vague to be propositions. The next two sections can be read in either order.
This depends on whether the reader is more interested in why plausibility
concepts might be used or on how they can be developed. Section 1 suggests when
and how a focus on plausibility might have advantages over a focus on truth.
Two main types of reasons are discussed, namely achieving consensus and
achieving clarity. Section 2 develops a thoughtful way of thinking about
personal plausibility intervals by using a betting interpretation. It then
develops the concepts of warranted and evidential plausibility, both for
personal plausibility intervals and for impersonal plausibility intervals.
Section 3 will be about specific applications of plausibility concepts. It will
not be written until I receive input from readers of the other sections. I
would like input of two types, namely imagined applications and implemented applications.
An imagined application would suggest a very specific use that has not been
carried out. However an imaginary application could tell what happens in a
fictional account of it being carried out.
Note: The
concept of an attitude and the concept of negotiation that use in this paper
are taken from Descriptive Psychology, a public net of theory neutral concepts
and conceptual tools created by Peter
Ossorio. These concepts are merely refinements of those widely used by people
to think about persons and their behavior, and an ordinary comprehension of
these concepts should be adequate for a basic understanding of their use in
this paper. For more a detailed presentation of these concepts and more
information go to the Descriptive Psychology part of my website or to the
website of the Society for Descriptive Psychology sdp.org.
For an introductory book on Descriptive Psychology, I recommend Persons, Behavior, and the World by Mary
Shideler.
SECTION 0 THE BASIC
CONCEPT
Main Perspective:
Arriving at our cabin, we found a strange dog on the porch. I decided to chase
it away. Charmayne asked me to be careful and remained in the car. We were both
implicitly considering the proposition that this dog is dangerous, which for
reference, I label as DG. I acted as if DG was only slightly plausible, while
she was treating DG as moderately plausible. This indicates several feature of
the main plausibility concept to be formulated. First I want to again stress
that by a proposition I mean a statement that proposes information that is
clear enough for the purposes at hand. Altho plausibility could be
conceptualized as an attribute of a proposition, as somehow related to the
extent to which it is reasonable to believe that it is true, there are reasons
why this is not the main plausibility concept that would serve the purposes I
have in mind. Foremost is the fact that I need a concept that relates to how a
person would act in a situation in which the proposition is relevant. In the case
of DG, I got a stick before trying to chase the dog from the porch. I would not
have taken this precaution if I had considered DG at the low end of barely
plausible. Had I considered DG as somewhat plausible, I would have been even
more careful. Another reason I want a relational concept is that plausibility
involves personal considerations that can be influenced by a variety of factors
other than evidence. A dog once attacked Charmayne. While this is evidence that
a strange dog might attack, our reactions to this evidence are naturally
different. My estimate of danger relates to my personal interactions with dogs
that seem aggressive, but who back down when boldly confronted. The essence of
the concept I call a personal plausibility attitude is given below.
A personal plausibility attitude is a
relation between a person P and a proposition C. It
indicates a willingness to act on C.
This may or may not be related to whether or not C is correct.
I am using the Descriptive Psychology concept of an
attitude. An attitude is a behavior tendency that is context-specific, in that
it is directed towards some focus of attention. Different plausibility
attitudes of P towards some proposition C indicate differences in the types of
action P might take. A plausibility attitude of P towards C will influence
behavior only in situations where C is somewhat relevant. P may not be aware of
these attitudes and may not even be thinking in terms of plausibility. Unless
we experience some hesitation, we usually regard propositions that we rely on
as if they were true.
Example 0: This example from around 1996
illustrates how a plausibility attitude can easily shift, especially when
almost nothing is at stake. Let C be the proposition that the Dow closed over
8500 while I was out working today. Shortly I will listen to the nightly
business report and will find out whether C is true or false. However before
then I modified my plausibility attitude towards C several times as indicated
below. This example is also a prelude to the main conceptual tool for
describing plausibility attitudes, namely by using a pair of numbers to
represent such an attitude in a manner to be explained shortly.
A0: I find C slightly to be somewhat
plausible, but having paid little attention recently, I feel uncertain about
what might be happening in the stock market. I do recall that the last time I
looked the Dow was about 8100, and that there had been some small gains in the
last few days. [20,40]
A1: My son calls and asks if I knew that
the Dow had gained over 300 points by noon. Immediately, C seems more plausible, perhaps even as high as fairly plausible. [45,75]
A2: When I ask him about the starting
level he said 8274. Suspecting that the 300 point rally probably did not hold I
now feel extremely uncertain about C. [10,99]
A3: He then said that by mid-afternoon it
had given back half the early gain but then there was a rally. From the tone of
his voice I was fairly certain that the Dow had finished with this rally. At
this point C seemed highly plausible and my level of certainty increased
considerably. [90,95]
A4: He tells me the closing average was
8534. C now seems totally plausible to me. [99,100]
Plausibility
Intervals: The number pairs above are
called plausibility intervals for various plausibility attitude.
They indicate the extent to which I considered C plausible at various points in
time.
A
plausibility interval for P’s plausibility attitude towards a proposition C is
an ordered pair of whole numbers [l,n], where 0 £ l
< n
£ 100. Thinking in terms of
a scale from 0 to 100, this means that P would say that C is at least as
plausible as l but a most as plausible as n.
The Use of Numbers:
My house is at 7739 Ahern. The next house is not at 7740 Ahern. Unlike
probabilities, to which we can apply the usual operation on real numbers, house
numbers indicate ordering rather than measuring. The use of numbers for
plausibility is more like their use for addresses than their use for
probabilities. Since thinking in terms of percentage is common, the range from
0 to 100 provides a useful heuristic tool for articulating a variety of
considerations about plausibility concepts. I restricted the values to whole
numbers to avoid any connotation that plausibility attitudes are measurable.
Above I used numbers in an off hand manner associated
with the phrases below. For instance, suppose P considers C plausible enough to
act on but not highly plausible. P might give an interval whose center is some
number from 71 to 89, using 80 as center unless P was inclined to do otherwise.
If P was completely uncertain about C, P might give the interval [0,100].
|
Barely Plausible: [1,10] |
Slightly Plausible: [10,30] |
Somewhat Plausible: [30,50] |
|
Moderately Plausible: [50,70] |
Fairly Plausible: [70,90] |
Highly Plausible: [90,100] |
The number pairs represent my intuitive feeling about
plausibility. The [20,40] after A0 is a
short way of saying that I find C at worst slightly plausible and at best
somewhat plausible. I could have used the pair [11,49]
for this had I wanted to also indicate even more uncertainty. The pair [25,45] would also indicate that I find C at worst slightly
plausible and at best somewhat plausible, but that I was leaning more towards
somewhat plausible. The [45,75] after A1 show that I have changed my
attitude, and that I then found C at worst only somewhat plausible and at best
fairly plausible, and that I was leaning towards moderately plausible. Note
that the extra information not only shifted me in that direction it also
increased my uncertainty. After the next information, I had almost no feeling
about whether the Dow had closed over 8500, except that I would not have said
that it was barely plausible. The information about the loss and the rally
increased my attitude at stage A3 to highly plausible, which I
represented as [90,95]. I read the [99,100] at A4
as totally plausible, meaning plausible beyond any doubts that I might actually
have, altho of course I could imagine that for some strange reason my son was
giving me incorrect information.
Plausibility and
Vague Statements: The above concept of a personal plausibility is a
relation between a person and a proposition. With modifications the concept of
a plausibility attitude towards statements that are too vague to be
propositions could also be considered. Let C be the statement that burning
leaves is bad for the environment. To the extent to which C does not propose
clear information, even with unlimited knowledge I could not determine if C is
true. My problem is that I find the idea of being bad for the environment too
vague in this context. On the other hand, I find that statement that a nuclear
war would be bad for the environment clear enough to be a proposition. Altho a
vague statement is conceptually incapable of being true or false, it is still
at least possible to act as if it was in some cases. I consider the concept of
a plausibility attitude towards C in that manner. Assuming that P has given no
thought to the possibility that C could be vague, then action possibilities in
relation to C abound. Attitudes toward C could influence such actions. Such
attitudes would also effect the discussions about C. With a wide-open attitude
P might burn leaves but also look for others ways to get rid of them. P might
implicitly interpret C as applying in the city but not in the country. However
attitudes other than plausibility ones could be involved. If P is indifferent
to the small impact of his own action then P might act as if C was highly
plausible in an argument, but still burn leaves.
Implausibility:
When we want to focus attention on why not to act on a proposition C, we might
call it highly implausible instead of barely plausible. Likewise, but with less
reluctant attitude about the implausibility of C we might call it fairly
implausible instead of slightly plausible.
Precision: As
explained above the use of numerical intervals is merely a way to compactly
indicate both a level of plausibility and an extent of uncertainty. These can
be used in an offhand manner with little or no regard for precision. If so
used, it should not be surprising if a person may have forgotten the interval
he used to indicate an attitude towards a proposition and then might later uses
a different interval to indicate this attitude even if it has not changed. For
many purposes there is little reason to take a plausibility intervals as
anything more that a casual heuristic tool.
To be more thoughtful about using a plausibility interval
we can interpret them as if they represented an attitude toward betting. Using
this interpretation, which will be developed in Section 2, my thoughtful [90,95] attitude given above relates to several betting
considerations. I would comfortably risk $90 to win $10 on a wager that C was
true. However I would definitely not risk $95 to win $5 on such a wager.
Furthermore I would be at least somewhat uncomfortable about risking $91to win
$9, and would be unlikely to risk $94 to win $6. On the other hand I would be
very happy to risk $80 to win $20, or $70 to win $30, $60 to win $40, etc.
SECTION 1 GROUNDS
FOR UTILIZING PLAUSIBILITY CONCEPTS
Plausibility and
Truth: While attempts have been made to formulate a logic
with more than two truth-values, or even a logic that could not be described in
terms of truth values, none of these have been widely accepted as useful. Altho
the ordinary concept of truth does not seem to be limited to its use in formal
logic, it still seems to be used mostly as if a proposition was either true or
false. Altho I use a more complex synthetic concept of truth, for a simple
proposition, truth can be thought of as an attribute of the proposition, altho
in cases an attribute that may be somewhat vague. The main ordinary maxim for
using this concept in relation to simple propositions is the following.
A simple proposition is true IFF it
accurately describes some aspect of something.
On the other hand, a personal plausibility attitude is a
relation between a proposition C and a person P. It relates to truth primarily
because it indicates P’s degree of willingness to act for some purpose as if C
were true. Instead of the stark two valued true or false expectations, personal
plausibility attitudes involve a wide variety of ratings. This is particularly
helpful when dealing with remote or unknown factors. Consider the claim that it
will rain tomorrow. We do not know enough atmospheric science to be able to
give a definite true or false to that statement, however we do have some
relevant knowledge and information. Forecasters even state the chance of rain
as a percentage. I suspect that these are not probabilities in the purely
mathematical sense. They might be better interpreted as impersonal evidential
plausibility attitudes rather than as probabilities. Whatever probabilities
might be involved in weather forecasting, there are a multitude of factors
involved that make it unlikely that any well-defined mathematical sample space
is a central feature of the models on which they are based.
Plausibility and
Legal Justice: One realm in which the utility of thinking about
plausibility is recognized is in legal matters. Even the locutions focus on
this, altho in our adversary system law enforcement official and prosecutors
act as if the defendant is guilty and the defense may try to convince the jury
that the defendant is innocent. Still in a criminal case what is called for is
guilty beyond a reasonable doubt, and no demand is made that a jury must
determine the truth. In jury deliberations, altho discussion may sound as if
truth was to be determined, the actual goal is a consensus on plausibility of
rather than certainty. If a juror follows this guideline then all that the
juror needs in order to vote not guilty is a warranted attitude of at least
slightly plausible towards the defendant’s plea. On the other hand if all
jurors have warranted attitudes of at most barely plausible then a verdict of
guilty should be rendered.
Likewise plausibility attitudes are even more apparent in
civil procedures. These are to be decided on the weight of evidence, and this
clearly need not be a matter of certainty. In one of the accounts that I
examined, weight of evidence was described as a 50% consideration. Interpreted
as plausibility, this would mean deciding for the plaintiff if a juror found
the plaintiff’s claim at least moderately plausible and the defendant’s claim
at most somewhat plausible.
Main Advantages of
Using Plausibility: There are at least two types of reasons that focusing
on plausibility attitudes at times might be more useful than on focusing on the
truth of a statement. One is to achieve a greater consensus, or to see why this
may be difficult. The gap between true and false is psychologically greater
than the gap between highly plausible and barely plausible. More important
thinking in terms of plausibility at least suggests that a somewhat greater
consensus might be feasible. Another reason for focusing on plausibility
attitudes is to bring a statement into better focus. This can be especially
useful in a discussion when the same words suggest different concepts to the
persons involved. Accounting for a plausibility attitude can be useful in
bringing out these differences. Bring a statement into better focus can have
behavioral utility even when no disagreement is involved. Reflecting on
plausibility could modify the way a person actions might have been influenced
by some statement not previously recognized as vague.
Consensus and clarity reasons are often interrelated.
Increasing clarity can show that differences were less significant than might
have been imagined. On the other hand it bringing statements into sharper focus
may make it apparent that the differences are even more significant than might
have been imagined. Even if clarity initially intensifies differences it can be
a prelude to useful negotiations. Without clarity, negotiation is likely to
degenerate in ways that mask even the consensus that might have been achieved.
Consensus: In
moving in the direction of consensus, thinking about personal plausibility
attitudes towards some proposition C could have a number of advantages over
focusing on whether C is true or false. Merely thinking about plausibility
attitudes sets the stage for consensus. On the other hand, to move from false
to true involve a major change, especially when the proposition being debated
is about something that cannot be easily verified or in which beliefs are
firmly entrenched. The very recognition that one has a plausibility attitude
allows for movement. Even with an extreme attitude such as [99,100], a person
merely needs to give some credence to something not previously considered in
order to move to [98,100]. This can also lead to considering more factors and
even willingness to look for more relevant information that might help in
moving towards consensus. Of course this will not happen if a person is set on
defending some cherished position. Example 1A below is an artificial
illustration in which considerable consensus is achieved. Section 3 is intended
for more useful illustrations.
Example 1A: Jan is a close friend of Ed.
They talk on the phone daily and see each other at least weekly. They know a
lot about each other’s habit and interests. Joe and Bob also know Ed, but not
as well as Jan knows him. Joe has a high respect for Jan’s opinions, but Bob
tends to distrusts Jan’s pinions. Sue has only seen Ed at a few meetings, but
she knows that Jan and Ed are close friends. Sunday evening the four of them
decide that they will stop by Ed’s before a Tuesday morning meeting. Knowing
that Ed will offer them breakfast, the following proposition C comes up for discussion.
C: There will
be at least 5 eggs in Ed’s refrigerator.
Each of these persons finds C at least slightly plausible,
but due to differences in personal information and other factors they have
different plausibility attitudes. Sue having almost no opinion can imagine C as
anywhere from barely plausible to highly plausible. Because Jan knows Ed so
well, she has a more definite attitude. Each person agrees to writes an initial
plausibility attitude towards C prior to any discussion or any attempt to acquire
more information.
Sue: [10,90] Joe:
[40,60] Bob: [20,40] Jan: [80,99]
After considering each other’s initial attitudes, but
without discussing the matter, they each decide to modify their own attitudes.
Sue: [40,99] Joe: [60,80] Bob: [10,30] Jan: [70,99]
Further discussion reveals the following information,
resulting in additional revisions.
¨
Jan and Joe and Bob all agree that Ed is not
allergic to eggs.
¨
Jan and Joe agree that Ed likes to eat eggs.
¨
Bob claims that Ed baked cookies Sunday, using
at least 6 eggs.
Sue: [0,100] Joe: [60,80] Bob: [10,50] Jan: [50,99]
Ed’s son comes in and tells them the information below,
which they all consider reliable.
¨
Ed shops once a week and bought 2 dozen eggs
Friday.
¨
Ed did not eat any eggs Saturday, but I did.
¨
Bob was right about Ed baking some cookies
Sunday afternoon.
Sue: [80,99] Joe:
[80,99] Bob: [70,99] Jan: [90,99]
Some of the reasons for the shifting attitudes in this
example should be apparent. Merely seeing that others had different attitudes
encouraged some shift towards consensus, at least when respect was involved.
The initial shifts are largely due to information about each other’s attitudes.
Sue’s and Joe shift because of Jan’s higher plausibility attitude, and this
also narrows Sue’s uncertainty. Bob’s shift is due to his lack of respect for
Jan. Jan simply become more uncertain because of the attitudes of the others.
Maybe they know something she does not know. Discussion that allows for sharing
reasons brings out information that did lead to a slightly greater consensus.
Further shifts are due mostly to information from their discussion, which tends
to lead to greater uncertainty. Finally they obtained some additional
information, which resulted in a high level of consensus. This information from
Ed’s son tends to shift them all towards fairly-to-highly plausible. It also
narrowed the uncertainty. Of course
none of these steps is guaranteed to lead towards consensus, but they at least
have a potential to do so, and are likely to in for a highly manifest claim. In
this particular case, just looking in Ed’s refrigerator would produce a total
consensus, but there are highly manifest claims that cannot be checked this
directly.
Consensual Factual
Negotiation: Negotiation is a way of arriving at a resolution of some
concern that is satisfactory to the parties involved. The concern can be about
what is the case or about what to do. The adjective ‘factual’ can be used when
the first of these is the primary concern. A negotiation will be classified as
consensual if the parties involved want to resolve matters in manner that
considers the perspective of all concerned as much as can be reasonably
expected and if the performance of the parties focuses on authentically looking
for a way to do so.
Descriptive Psychology represents a form of consensual
factual negotiation process as a social practice that can be broken into 4
stages: taking positions, criticizing and defending these positions, adjusting
these positions if necessary, drawing conclusions.
There is no essential reason that a consensual factual negotiation should focus
only on truth claims. In some cases more progress might be made if personal
plausibility attitudes were examined. Instead of taking fixed positions, some
extra effort could be given to specifying personal plausibility for these
positions. Instead of merely criticizing and defending positions, an
explanation of why these attitudes seem personally warranted could be given,
including reasons that the parties have for treating there
own positions as less than totally plausible. Making revisions would
involve indicating even minor shifts in plausibility attitudes. Finally,
drawing conclusions would focus both on how much progress was made towards on
consensus and on the degree of remaining difference. This stage should also
focus on what to do about remaining difference, at least if a greater consensus
seems desirable.
Achieving
Clarity: People can act as if a claim is true without even considering that
it might be vague. One advantage of focusing on plausibility is that by
focusing on uncertainty it sets a stage for thinking about reasons that the
claim at issue may be vague. On the other hand, focusing on truth tends to
presuppose that the claim is clear. If the claim is about manifest matters,
feedback can bring clarity. If the vagueness is due to conceptual differences
about a statement then discussing plausibility attitudes can help bring
clarity. Focusing on your own personal plausibility attitude can be a way of
achieving clarity about your own use of a statement, even if you do so without
any discussion with anyone else. Of course focusing on plausibility attitudes
is not the only tool that can be used to help achieve clarity.
Example 1B: Ray
says that picking up a water snake is dangerous and I disagree. I pick one up.
It clamps down on the skin between my thumb and index finger. It draws a
trivial amount of blood, but causes no pain. This initiates a clarification of
our claims that helps us see that both of our plausibility attitudes are
personally warranted, altho they are about different claims. He says that altho
the snake is not poison, its bite could cause an infection. This is not what I
meant, but if this is what Ray meant then I find his claim slightly plausible.
His statement may have been somewhat vague to each of us when we started, but
feedback shows that the main lack of clarity was not in our individual
interpretations but with
differences in them. I tried to demonstrate that the
statement was implausible by picking up the snake. A discussion of plausibility
attitudes could have provided a less dramatic way to show that C proposed
different types of information us.
Influencing
Behavior: Altho the purpose of making a statement may be to propose
information, they can also be used to influence behavior. I am told that it is
almost six o’clock and so I come in from the garden. In this case the statement
is clear and compact. The influence on my behavior is useful to me, and it
would be redundant to add an imperative sentence telling me to come in. This is
the case with a wide variety of statements about ordinary manners in which
information is proposed in order to influence behavior. With such statements
considering plausibility is largely irrelevant. However some statements are
motivated much more by a desire to influence behavior than by a desire to
propose information. An advertisement may give information, but this is not its
primary purpose. Furthermore they may influence behavior in ways that would not
be useful to the actor. Clarification of any information such a statement might
be proposing can help counter a tendency to be influenced by it. Again focusing
on plausibility attitudes is one way to clarify the information.
A statement does not even have to propose information in
order to influence behavior. It only needs to seem as if it does. Thus vague
statements can influence behavior, and as with advertising this may be their
main purpose. When a statement is about remote matters such as values or social
policies, it may often be more about influencing behavior than about providing
information. Since many statements about manifest situations are clear enough
for the purposes at hand, we have a tendency to also treat unclear statements
about remote matters as if they were propositions. Cultivating a habit of
thinking about their plausibility is one way to counter this tendency,
especially if you consider whether your attitude is warranted. Doing so is more
likely to provide the flexibility needed to bring a statement into better focus
than merely than marshalling reasons for defending a
fixed stance on the statement.
For a vague statement C about remote matters, the only way
some people may react to C is by asserting it and arguing about it. The desire
to maintain or refute C may interfere with even considering that C might be
vague. I know that I make many statements about remote matters without even
realizing that they are vague to me. Exploring differences in plausibility
attitudes can help me see why my statement was vague. This could help me
clarify it, at least to myself. Likewise people often make statements about
remote matters that seem vague to me, and I usually suspect that they are vague
even to the people making them. Given a willingness to acknowledge vague
thinking, considering plausibility attitudes could be a useful in obtaining
greater clarity. Even when it is not, I find it useful to spot that what is
being said is vague to me. This tends to be the case with a multitude of claims
about social policies and values. Unless a person is willing to search for
clarity and to focus on plausibility, I have little interest in discussing such
statements.
Example 1C: Let
C be the statement that the war on drugs is a disaster. The libertarian party
would like us to find this so plausible that would be inclined to vote
libertarian. Of course how a person acts on a proposition also depends on a
variety of attitudes. An alternative way to act as if C was plausible would be to
vote for candidates who want to put more effort the interdiction of the drug
traffic. Using the word disaster instead of failure is one way to counter that
tendency. The concept of a disaster may be vaguer than the concept of a failure
in this context, but it suggests that a radical change is needed. When
challenging an entrenched policy, a vague but powerful statement can rally the
opponents and possibly instill doubts in some who have passively accepted the
policy. Reflecting on my plausibility attitude towards C, I see that I have
treated C as true altho C is not clear enough to me to be a proposition. I
would not deliberately treat a vague statement as if it was true, nor even act
as if it was totally plausible. Spotting that a statement is vague, there are
several options; try to clarify it, simply refrain from acting on it in any
way, deliberately leave it vague but also adopt a plausibility attitude towards
it. This last option is what I chose to do with C, acting as if my plausibility
attitude towards C was [70, 100]. I do this because C represents a complex of
propositions that I have not formulated, but which I would expect to find in
the fairly plausible or highly plausible ranges. Altho I could formulate this
complex, it would be tedious. Since the only way I act on C is to use it as a
summary of implicit propositions, as long as the vagueness of C in focus, this
seems like an appropriate way of dealing with it.
Total Plausibility
and Truth: Saying that C is totally plausible means that C is plausible
beyond sensible doubt, i.e. only by some flight of fantasy could we currently
imagine otherwise. For instance I find the claim that I am using a word
processor as I edit this paper totally plausible, altho I can imagine the word
processor has been disabled and that what appears on the screen is due to some
strange virus that has infected my computer. The concept of totally implausible
is treated in a similar manner. An attitude of totally plausible towards C is
both conceptually and pragmatically different from believing that C is true.
For one thing, to explicitly acknowledge such an attitude is to remain at least
somewhat open to changing it. However regarding C as true or as totally
plausible usually has the same influence on action, and it is often more
convenient to think of C as being true. This is especially the case for our
basic reliable knowledge, as well as a multitude of thing we take for granted
in our daily activity. I get up in the morning with some plans for what I might
do. All of these presuppose thing I do not explicitly consider. I act as if it
there is hot water in our water heater, as if there is a spoon in the kitchen,
as if the roof is on our cabin, etc. Later most of these are verified to the
extent that they need to be. Of course, some things I regarded as true turn out
to be false. This is usually at most a minor nuisance. I was sure there was a
can of peas in storage, but as there was not, we had spinach instead. On
reflection I would say that most of these things that I took for granted were
merely things that I would have considered totally plausible, had it occurred
to me to think this way. In such ordinary matters I easily accept mistakes and
see no reason not to think primarily in terms of true or false. I merely use
the very ordinary criteria that in many matters thinking of what I take for
granted as being true is not only convenient but also justified by the
competence I have in evaluating such matters. It is when I want to reflect more
deeply on my understanding of epistemic concepts that I focus on the fact that
I much of what I take as true I might instead regard as totally plausible.
Side Remark: I
often use [99,100] to
indicate totally plausible. Since an attitude relates to action, it is more
appropriate to say that C is totally plausible means I would not hesitate to
act as if C was true in any situation where C was relevant. If [99,100] seems
weak for the concept of totally plausible, consider betting. I would risk 99 to win 1, but
not 100 to win 0. This is certainly the case with anything I consider totally
plausible. Had I allowed rational numbers for interval endpoints, I could have
used a narrower interval for the concept of totally plausible. However I do not
want to suggest that plausibility attitudes are actually measurable.
Epistemic Utility: Achieving
greater consensus and achieving more clarity are fairly manifest ordinary
reasons for focusing on plausibility attitudes. I also have a more remote
epistemic reason, namely that it helps me reflect on my epistemic concepts. One
aspect of understanding epistemic concepts is to realize that even when
reasonably challenged, I may act as if my claim was true. As a mundane example,
I was sure that there was a can of peas in storage, but Charmayne says she
cannot find any. I still claim that we have some. This is partially justified
by the fact that I organized our storage areas and that I remember seeing them
there, as well as by the fact that I often find items that she overlooks.
However given what I know at the time, I should at best regard my claim as
totally plausible. Plausibility easily becomes relevant as I search in vain,
but is quickly forgotten as I finally decide my claim was false. Reflecting on
plausibility helps me realize the utility of cultivating the habit of giving
more tentative responses when ordinary claims are challenged. My ideal is to
have only a prudential interest in being right, not only about such
trivialities, but about any claims I make. Cultivating a more tentative
attitude towards propositions about manifest situations carries over to those
about more remote ones. In addition I frequently remind myself that evidence
for remote propositions tends to be complex. Thus in claiming something like
“last years tax cut had effect X.”, I would find
discussions involving plausibility more useful than arguments that try to
convince. It seems to be difficult for most people to regard cherished
positions on complex issue in terms of plausibility, and for that reason I find
myself slipping back into a truth oriented thinking
when such matters are being discussed. It is only by being vigilant that I can
take what I consider a more appropriate plausibility perspective.
SECTION 2
DEVELOPING PLAUSIBILITY CONCEPTS
The Betting
Interpretation: Betting involves a willingness to take a chance at certain
odds, and thus involves an attitude. For a simple case consider some
proposition C and suppose P would consider making a reasonable size bet that C
will turn out to be true. Odds are usually stated as ratio, such as 3:2. To
accept a bet with 3:2 odds is to risk an amount 2x to
gain an amount 3x. Likewise to take a bet at 2:3 odds means to risk 3x to win 2x. For easy comparison, think of 3:2 as 60:40,
4:1 as 80:20, 9:11 as 45:55, i.e. as ratios whose parts sum to 100. This way, each can be coded as a single risk
number: 40, 20, 55. The second part of the ratio is
used because it indicates the amount to be risked in order to gain the other
part. Thus a higher number indicates a greater confidence in the proposition
being considered. A plausibility attitude is represented as an interval rather
than a single number because one important aspect of such an attitude is the
extent to which it is wide or narrow. To say that my plausibility attitude is
represented by [20,55] indicates that I would gladly bet on C if given odds of
80:20 odds or better but would definitely refuse to bet given odds of 45:55 or
worse. This betting type of interpretation can be taken primarily as an
analogy, but there are situations in which it seems reasonable to identify a
plausibility attitude with a betting attitude. The use of numbers is merely a
convenience for indicating differences in attitudes. They are intended to
indicate rather than measure attitudes, and for many purposes I see no need
further qualify any distinction between a betting attitude and a plausibility
attitude. However qualifications can always be imagined. In the next example I
have implicitly assumed that the reason P would not bet at 4:1odds is related
to his attitude about the plausibility of his team winning. If he needed $80000
to pay a loan shark and only had $20000, then his actual betting attitude could
differ from his plausibility attitude.
Example 2A Let C be
the proposition that the Celtics will win the NBA championship next year.
Suppose Sal would not even consider betting on C if given odds of 4:1, would
not hesitate to bet on C given 9:1 odds, and would be undecided for odds
between 9:1 and 4:1. Since these odds are 90:10 and 80:20, his attitude towards
betting on C can then be represented by the interval [10,20].
With certain qualifications, this interval also represents his plausibility
attitude towards C. End points indicate personal comfort levels at a particular
point in time. It may seem unlikely that Sal would really jump at a chance to
bet at 90:10 odds but hesitate at 89:11 odds. Perhaps, but his reasons may be
fairly arbitrary. Sal may merely find 90:10 easier to understand because it
converts to 9:1.
Example 2B: Let C be the proposition that
in the next hard rain the top mantle over my fireplace will remain dry. Had I
made this prediction a month ago my plausibility attitude would have been
something like [1,50]. In terms of betting this means
I would gladly risk 1 to win 99, i.e. bet at 99:1 odds. However I would
definitely not bet at even odds. Yesterday we found cracks in the roof tar
around the chimney and patched them. Now my attitude towards C is in the
fairly-to-highly plausible range say [80,95].
Present
Plausibility: Altho the concept of a plausibility attitude interval
sometimes applies to something that might happen in the future, it also
involves relevant things that could reasonably be known about the present. In
the Example 2B the plausibility attitudes focused on what would happen if it
rained. I could just as easily substitute my attitude toward the proposition
about the roof tar, which is actually more relevant to my concerns. It was
having observed water on the mantle that motivated me to inspect the tar, and
filling the cracks was intended to prevent the leaking. My [80,95] attitude was more about having fixed the cause of a
leak than about the future effect of a rain. I focused on rain primarily
because this was why I was worried about the leak. In general, as long as
chance is not a significant factor, most plausibility attitudes about the
future would be reducible to plausibility attitudes about the present. It is
the fact that we act on what we tend to believe about the present and the past
that motivated me to formulate plausibility concepts. This applies even to
betting. Altho betting usually relates to future events, the analogy to betting
does not depend on temporal considerations. Given 9:1 odds, I would gladly bet
that a coin already fairly flipped but not yet examine is tails up.
Example 2C: Let C be the proposition that
there is life on Mars. My initial reaction is that C is barely plausible,
perhaps expressing this as plausibility [0,5]. As a
betting attitude, suppose that the truth-value of C could be determined in the
near future. Then I would bet on C being true at 100:0 odds but I would not bet
at 19:1 odds. Since a plausibility attitude is a relation between a person and
a proposition occurring at a particular time, this may change. Given a new
probe finding fairly strong evidence of life on Mars I might change my attitude
to highly plausible, say [90,95]. Which attitude I
take might affect the strategy I would use in advocating a manned mission to
Mars. The above statement about life on Mars was not vague for me. I implicitly
knew that I was thinking of life as including microscopic life. Instead of
barely plausible, Marge said totally implausible because she was thinking of
life as a complex ecosystem involving higher order plants and animals. In
explaining my plausibility attitude this difference became apparent. We easily
saw that our attitudes only appeared to differ because we were using this
statement for different propositions. It is fairly easy to indicate the
propositions associated with statements about life on Mars. The difference in
the concepts suggested by the words is minor and the kind of information that
might be relevant is fairly clear-cut. With statements for which this is not
the case, it could take more effort to see that at least part of the difference
in attitudes is due to the difference in concepts.
Utility of the
Betting Interpretation: When chasing the dog from the porch I had given no
thought to any plausibility attitudes involved. In fact I did not even
formulate the proposition DG until several days after the incident. Since
plausibility attitude involve a tendency to act, rather than to reflect on
what-to-do, this is typical of the way we usually treat most of our attitudes.
I act on many plausibility attitudes, but I formulate few of them and consider
plausibility interval only rarely. Otherwise little would get done. Formulating
DG and reflecting on how to think about my plausibility attitude towards DG in
terms of betting can have no effect on what I did. Nor do I intend it to help
me decide how to act the next time a dog appears on our porch. Why then do I
find the concept of a plausibility attitude useful, and why do I find it useful
to relate it to betting attitudes? My answer may seem simplistic. Reflecting on
my attitudes helps me understand my self and my
world, and as a result it increases my options. Perhaps reflecting on DG may
have only some influence on my plausibility attitudes towards dog attacks, but
this is not its purpose. Its main impact has been on my overall understanding of
how I might think more clearly about plausibility attitudes and how this way of
thinking could have some utility.
It is the betting interpretation that provides the clarity
I need. Using it in several examples has made me more sensitive the conjectural
nature of the propositions that implicitly influence what I do and say, altho
not yet to the extent that I would like this to happen. This interpretation is
also a tool I can use to communicate about my plausibility attitudes, at least
to anyone willing to take the effort to understand them. I hope it is a tool
that other could use to better understand and communicate their attitudes
towards various propositions. Altho this tool is not directly useful for
attitudes that are not towards propositions, most attitudes relate to some
propositions that could be formulated. Plausibility attitudes towards these
propositions could provide insights into other attitudes. Since the effort in
formulating statements with sufficient clarity to be propositions can be considerable,
this may not seem worth the effort if the only purpose is to understand a
specific attitude. Since I enjoy the effort, this is not deterrence.
Furthermore my purpose in formulating such propositions is always broader than
this. Understanding a specific attitude influences my understanding of my
epistemic concepts.
Whether person would actually bet could depend on factors
other than odds. So without some qualifications a person’s attitude towards
betting on a proposition may differ from that person’s plausibility attitude
towards it. The following discussion of qualifications is motivated by a desire
for greater clarity than may be called for by considerations of direct utility.
It may seem somewhat tedious and artificial, so skip it if it seems uninteresting.
Qualifications: A
person’s attitude towards betting often depends on the amount of the bet rather
than just on the odds. For instance at Stage A2 in Example 0, I gave my plausibility attitude as
[10,99]. As a betting attitude, this means I would
definitely bet at odds of 90:10 and would definitely not bet at odds of 1:99.
However I qualified this by indicating a reasonable wager. This is because my
attitude toward betting also depends on the amount of the wager. I certainly
would not have bet $100000 at even better odds. Even a small risk of loosing this outweighs prospects of becoming a millionaire.
Likewise I would not actually wager $1 because the winning would be too small
to compensate for placing the bet, and in addition to this I have a bias
against petty gambling and this attitude has little to do with the odds. In
order to make the betting interpretation work for me, I interpret my betting
attitude in terms an imaginary world in which I can effortlessly make imaginary
bets. With a playful goal of increasing my financial status in this world, my
plausibility attitudes are likely to coincide with my betting attitudes.
Another qualification about the relationship between
betting and plausibility attitudes can be illustrated by looking back at the
proposition DG mentioned earlier. Being at the low end of slightly plausible, I
could represent my attitude by [10,20]. As a betting
attitude this means I would risk 10 to win 90 but would not risk 20 to win 80.
On reflection, this seems about right, altho precision is hardly called for.
However my plausibility attitude differs in a major way from the way I would
act in the betting interpretation. The relation of risk to payoff was not very
clear. Furthermore not acting on C did not mean that I could not get the
payoff. I could hedge my bet by choosing a better one. In getting a large stick
I decided to bet instead on the proposition that the dog could not successfully
attack me if had this stick. This was a proposition that I considered highly
plausibly [95,99], so obtaining the stick seemed worth
the extra effort. The effort was minimal and the apparent risk was considerably
reduced.
Plausibility
Differs from Probability: In a game such as roulette the odds have a fairly
direct relationship to the likely hood of what might actually happen, altho
people playing roulette accept poorer odds than the probabilities involved.
People also bet when there is no way to even calculate probabilities. Suppose
we pretend that the odds in Example b
are probabilities. Jumping at 9:1 odds is to act as if the probability of the
team winning was better than 1 out of 10 or 10%. Being unwilling to bet on 4:1 odds, is to act as if the probability of their winning is
certainly not as great as 1out of 5 or 20%. To be unsure of 17:3 odds is to be
unsure about a probability of 3 out of 20 or 15%. In many betting games there
is a clear sample space from which to calculate the odds for a fair game.
However in Example 2A I have no
idea of what sample space to use, so acting as mathematical probabilities were
involved is merely a heuristic device. Thus Sal’s attitude towards this bet
does not represent the probability of the Celtics winning the championship.
Instead it at most represents the plausibility that he associates with the proposition
C. Unlike a situation for which probability can be used to assign a definite
value to uncertainty, plausibility usually involves a more amorphous
uncertainty. To account for this, I use an interval for his plausibility
attitude towards C, namely [10%,20%] or more briefly
[10,20]. Unfortunately, persons often talk in terms of probability when
plausibility would be more appropriate. For instance if the treasury secretary
is asked about the probability of an economic recovery by the end of the year,
it seems unlikely the answer will involve a conceptual claim about some sample
space. I strongly suspect the answer to be more indicative of a plausibility
attitude. This is not to denigrate the intent of the question or his response.
His plausibility attitude should be of the type that I will later classify as
evidential, and some of his actions may be influenced by this attitude.
I want to stress that the even when related to betting
attitudes, the concept of a plausibility attitude in no way depends on the
mathematical concept of probability. Betting involves a degree of willingness
to take a chance, which often is not related to probability and which occurs
when there is no clear way to figure probabilities. Thus the concept of betting
does not depend on the concept of probability. The mathematical concept of
probability was not even formulated until the 16th century. Clearly
people were making bets long before this. Furthermore many bets are still being
placed with little or no regard to mathematical probabilities. In fact the work
of Pascal and Fermat in probability was at least partially motivated by a
question posed by a gambler about the division of stakes in a game of dice.
Warranted
Plausibility Attitudes: Since an attitude relates to choosing actions, I am
not interested in merely identifying my willingness to act. I also want
my plausibility attitudes to be warranted enough for some purpose. I
represented my attitude towards DG as [10,20]. Since
the dog on our porch turned out to be extremely docile, I think my attitude
towards DG was warranted enough to act as I did. Likewise [11, 25] and a
variety of other intervals would have been just as warranted. Had it turned out
otherwise, such attitudes might have seemed unwarranted. However outcomes alone
are not sufficient to determine whether or not an attitude is warranted. DG
turning out to be false once tested does not suggest that a plausibility
attitude of [0,1] would have been warranted. Given
what I could reasonably be expected to know before confronting the dog, only a
much more open attitude would have been warranted. Furthermore altho this
particular dog turned out to be docile, perhaps my attitude was a matter of
false confidence and not being harmed was just a matter of luck on my part. I claim
my attitude was warranted because of my competence, i.e. because of what I know
about dogs and my ability judge this dog’s reactions when we arrived. I have
several ways of thinking about a plausibility attitude being warranted. All of
them are somewhat vague, and there is no sharp line dividing warranted and
unwarranted attitudes.
A personal
plausibility attitude A towards C is warranted for P to extent that it involves
an adequate understanding and interpretation of the information that P could
reasonably be expected to consider about whether C is true or will turn out to
be true.
The ‘reasonably be expected to consider’ qualification is
one of several reasons that the concept of being warranted can be vague,
especially when taken out of context. However given the context it can be easy
to apply, and this qualification is essential to the concept I want. Altho P
might be able to use bribery to obtain insider information about the prospects
of a stock, it is easy to imagine that this would not be something P could be
reasonably expected to consider. A warranted attitude for P would differ from a
warranted attitude for a person willing to break the law. In general, P can
only be expected to consider information that P can reasonably be expected to
obtain, given P’s characteristics and the circumstances involved. Because
different people could reasonably know different things and could also have
different analytic and synthetic abilities, widely different attitudes toward a
proposition could be warranted for different people. Furthermore what a single
person could reasonably know is not static and plausibility attitudes are not
precise. There would often be more than one warranted attitude for a person
towards a proposition and this could change as things evolve.
Consider the initial attitudes in Example 1A from Section
1. With the information given and the condition about expressing their initial
attitudes, it is possible that all of these attitudes were warranted. However
an attitude of [1,99] or of [20,80] would also have
been warranted for Sue. As they obtain more information none of their initial
attitudes would be warranted. However unless Bob has good reasons not to trust
Jan’s judgement that are relevant to the issue, his
[10,30] attitude seems less warranted to me. Without
more information about these persons it would be impossible to say to what
extent his final attitude is warranted, but I could easily imagine that it
might be warranted.
Pragmatically
Warranted: The most manifest concept of warranted that I consider involves
being warranted in relation to some specific purpose or set of purposes. I
refer to this as being pragmatically warranted, and this means that for the
purposes at hand, obtaining additional relevant knowledge would involve doing
something that would not have positive utility for P. Altho my attitudes in Example 0 shifted
rapidly as I passively gained information, I regard each of them as
pragmatically warranted in relation to mild curiosity. Altho I could have
interrupted to ask about the closing, this would not have served a useful
purpose. Had I a more significant purpose, only A4 would have been
warranted, since I could reasonably be expected to ask immediately about the
closing if anything major was at stake.
Example 2D: While
walking, Charmayne and I were discussing plausibility concepts when we heard
something in the woods some distance behind us. Turning we got a glimpse of a
tail and movement of foliage. We both concluded that we were fairly certain
that it was not a squirrel. Other than our fleeting visual and auditory
impressions, and what we know about the size of squirrels, there was little
else that we could have known that would have been relevant. Yet what we did
know was enough to say that our attitudes of barely plausible (or highly
implausible) to it being a squirrel were warranted. We also noted that an
attitude of totally implausible to it being as an elephant would be warranted.
We had different attitude towards it being a deer, but we agreed that our perceptual
differences warranted different attitudes. My first reaction was fairly
implausible, but after a little discussion I decided that a much more open
attitude might be more warranted, especially after considering what else it
might have been. Again only mild curiosity was involved in our conjectures, and
so these attitudes were at least pragmatically warranted. Altho we might have
obtained more information by going back to where we saw the movement, given
only mild curiosity, whatever we might have found that would have been relevant
is not something we could reasonably be expected to consider. In fact given our
limited abilities in regard to animal signs, what we might have observed was
unlikely to be anything we could reasonably expected to consider. For an
experienced tracker P, an attitude similar to ours might have been
pragmatically warranted in relation to mild curiosity, but it might not be more
generally warranted.
Narrow Attitudes:
A variety of attitudes towards DG could have been warranted enough for purposes
at hand, but not one as narrow or as low as [0,1]. Such an attitude would have
been warranted if it had been our neighbor’s dog, but extreme attitudes such as
[0,1] and [99,100] are warranted only when know enough
that plausibility would not normally be considered. Other narrow plausibility
attitudes can be warranted under fairly special circumstances. For example if a
fair coin has been flipped and not examined, then an attitude of [49,51] toward it being heads is certainly warranted for many
purposes.
Impersonally
Warranted: So far I have only considered plausibility intervals as being
personally warranted. I also want to be able to say that even if P’s
plausibility attitude was warranted for P, it was not really warranted. Perhaps
P was not competent to evaluate the proposition. This suggests a concept of a
plausibility interval for a proposition being impersonally warranted.
A
plausibility interval for C is impersonally warranted to the extent that the
persons who are qualified enough to evaluate the plausibility of C would
consider this interval as a warranted plausibility attitude towards C, if they
considered what they could reasonably know about C.
Since this is a consensus concept involving a degree of
competence, there are some caveats involved in using it. First note that just
as various compatible intervals for C can be personally warranted, various
compatible intervals for C can be impersonally warranted. However, it may be
that no interval is impersonally warranted for C, and even if there are
impersonally warranted intervals for C they may be difficult or even impossible
to determine. For a more precise concept we would need to specify the degree of
consensus that is demanded.
Example 2E: Consider
again the proposition DG about the dog not attacking. Is the interval [10,20] impersonally warranted? Since Charmayne and I where the
only people to observe the dog at the relevant time, let us suppose that we
were the only people who could have been qualified to evaluate the plausibility
of DG. Charmayne and I agreed that I was better qualified. However we might be
wrong about this. Perhaps she was qualified enough for her attitude to be
considered, in which case [10,20] would not be
impersonally warranted. Perhaps neither of us was qualified, in which case no
plausibility interval would be impersonally warranted. In saying this, I
supposed being qualified as being actually qualified. There are clearly many
others who were potentially qualified, i.e. would have been qualified if they
had the opportunity to observe the dog. Including them might mean that there
was one or more impersonally warranted attitude, altho there might be no way to
determine what these were. While both Charmayne and I agreed that potentially
qualified persons might have found [10,20] as
warranted, this is not something either of us knew how to verify.
Example 2F: Let
G be the claim that the earth revolves around the sun. Altho dispute about G
did not focus on plausibility, suppose Galileo’s plausibility attitude towards
G was [95,100] after he observed the moons of Jupiter. This seems not only
warranted for Galileo, but also a warranted impersonal plausibility attitude.
Many critics of Galileo had an adequate understanding and interpretation of the
information they could reasonably know about G, but lacked the background to
understand the principles on which a telescope is based. For such critics a
personal plausibility attitude of [10,90] might have
been warranted, but since they lacked the competence to evaluate the plausibility
of G, their attitudes are not relevant to whether an impersonal plausibility
interval was warranted. After the work done by Galileo the only warranted
plausibility intervals for G were those in the range of highly plausible. The
extent to which a plausibility interval is warranted can vary with time. For
the last few centuries the only warranted plausibility attitude for G has been
[99,100], so much so that we usually merely think of G as
true. I do not have enough information to consider what impersonal plausibility
intervals would have been warranted before his telescopic observations and his
studies of motion, but perhaps something as open as [60,100] might have been
impersonally warranted at that time. Prior to being proposed, no attitude towards
G is conceptually possible, and the statement that the earth revolves around
the sun would not even propose the same information as G in a time prior to
Greek astronomy.
Evidential
Plausibility Attitudes: One factor that provides a reason to consider
whether an attitude is warranted is the extent that it based on relevant
evidence that can be articulated and examined. This suggests the concept of an
evidential attitude.
A personal plausibility attitude towards C
is evidential for P to the extent that it is based on the
information relevant to C that P could
reasonably know and articulate and examine.
I am fairly confident that my attitude towards DG was
pragmatically evidential. Of course there are things I could have reasonably
done to make it more evidential. Looking for studies about dog attacks was not
one of these things. However I could have made a more careful observation of
this dog, but implicitly believing that my attitude was pragmatically
warranted, this did not occur to me. Altho being evidential and being warranted
are related there is one major difference. Being evidential is not a sufficient
condition for being warranted. Being warranted also involves competence in
adequately applying the evidence. Nor is being evidential a conceptually
necessary condition for being warranted. As conceptualized, a warranted
attitude cannot ignore evidence that can be examined, but this leaves open the
extent to which it might involve other factors. I do not believe that any of my
warranted attitudes involve mystical powers, but I cannot rule this out by
purely conceptual consideration.
Being evidential also applies to impersonal plausibility
intervals, and it is one of the factors providing a reason to consider whether
a plausibility interval is impersonally warranted is the extent to which it is
impersonally evidential. A plausibility interval for a proposition C is
impersonally evidential to the extent that it would be an acceptable evidential
plausibility attitude for most persons who would be competent to evaluate the
relevant evidence.
Objective
Plausibility: In thinking about whether or not a plausibility interval for
a proposition C is impersonally evidential or impersonally warranted, I am
implicitly thinking about the plausibility of C rather than about a personal
attitude towards C. Thus when I say that
C is highly plausible, and I say this as if this is an attribute of C rather
than an expression of my attitude, I am tempted to say that what I mean by this
is that an interval in this range is impersonally warranted. However I am
reluctant to conceptualize it this way. The conceptualization of being
warranted is at least partially intersubjective. I
have yet to decide if it would be useful to try to formulate a concept of
plausibility that is a totally objective attribute of a proposition. Nor do I
know how I would do so. Currently I use a vague concept of this type, as if a
plausibility attitude is some how objectively
grounded in what could reasonably known, but does not
in any way depend on the considerations of qualified persons.
A heuristic concept of a correct objective plausibility is
easy to give, altho I have doubts about its utility. Imagine an infinitely
competent person objectively evaluating what could be reasonably known at the
time and deciding the extent of the plausibility of C. Also pretend that this person has a much more
precise concept of how to assign intervals to attitudes than any concept that
we have been able to imagine. The plausibility interval this person would
assign to C could be conceptualized as the correct objective one.
Not having infinite competence, there may be no way to
determine a correct objective plausibility of C at a time T. However I am still
willing say that the claim G about the earth and sun is currently totally
plausible in an objective sense. I am also willing to say that [49,51] is a correct objective plausibility interval for the
fair coin proposition mentioned earlier. That I could be wrong about such
matters is no more important to me than that I could be wrong about a multitude
of other matters that I have no reason to doubt. Furthermore not knowing a
correct objective plausibility interval for a claim does not prevent me from
being fairly certain about some intervals that do not qualify. Whatever the
objective plausibility of G was when Galileo proposed it, it was not in the
range of barely plausible. In spite of these considerations I have little
commitment to the utility of the concept objective plausibility. However when I
use this concept, the extent to which an impersonal plausibility interval for C
is warranted is at least one factor in deciding the extent to that C is
objectively plausible.