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INTRODUCTORY: Part
5
Categorical
and Hypothetical Propositions
by Jonathan Dolhenty, Ph.D.
When we look at the relationship between the two
main groups of propositions, we will notice
immediately that they are not exclusive of each
other. Of course, single and multiple propositions
do exclude each other and categorical and
hypothetical propositions do exclude each other.
But while the single propositions are always
categorical and the hypothetical propositions are
always multiple, the categorical propositions may
be either single or multiple.
Single
Categorical Propositions
The categorical proposition makes a direct
assertion of agreement or disagreement between the
subject and the predicate.
Simple Categorical Propositions
The single categorical proposition contains only
a single sentence in its construction. It contains
one subject, one predicate, and the copula.
If these elements of the sentence are without
any qualification or composition, it is a simple
categorical proposition. Examples: "Gold is an
ore," "Jack is tall," "Man is rational." There
should be no difficulty with these types of
propositions since they are so simple.
Composite Categorical Propositions
If, however, a qualification or composition
enters into the subject or predicate or copula, we
have a composite single categorical proposition,
and these may be of two types: complex propositions
and modal propositions.
Two Kinds of Composite Propositions
The Complex
Proposition
The complex proposition is a composite single
sentence in which both the subject and the
predicate or either one is a complex term.
Comparative examples: "Man" is a simple term. But
"Good man" or "Learned man" or "Intelligent man"
are complex terms. These latter terms used a
subjects or predicates, or any verb which expresses
past or future time used as a predicate, makes the
sentence a complex proposition.
Consider the following propositions:
- Man is a rational animal.
- The heat of the sun will make the flowers
bloom in the spring.
- Seeing-eye dogs are faithful
companions.
In the above propositions, there is only one
judgment, with one subject and one predicate. But
the subject or the predicate in each proposition is
a qualified (complex) term.
The Modal
Proposition
The modal proposition is a composite single
sentence in which the copula is so modified as to
express the manner or mode in which the predicate
belongs to the subject. The qualification does not
affect the subject or the predicate. It affects the
copula itself. It states whether the objective
connection between the subject and the predicate,
expressed by the copula, is necessary, impossible,
possible, or contingent. There are, then, four
different modes, each producing a different type of
proposition.
Mode 1. The necessary modal
proposition states that the predicate belongs to
the subject, and must belong to it. Examples: "A
circle is round," "Man is an animal," "Two plus two
equal four."
Mode 2. The impossible proposition
states that the predicate does not and cannot
belong to the subject. Examples: "A square has five
sides," "A dog is a rational animal," "Four plus
four equal nine."
Mode 3. The possible proposition
states that the predicate is not actually found in
the subject, but it might be. Examples: "A diabetic
may go into a coma," "My truck can go over 100
miles per hour," "Paul may be a good student."
Mode 4. The contingent proposition
states that the predicate actually belongs to the
subject, but it need not. Examples: "These students
need not attain good grades," "It is not necessary
that the dog keep on barking," "I need not go to
the dance Friday night."
Multiple
Categorical Propositions
Multiple categoricals are propositions which
contain two or more sentences in their very
construction. Some of these are overtly multiple
and some are covertly multiple. The covertly
multiple propositions are called exponibles.
Overtly Multiple Categoricals
The overtly multiple categoricals are plainly
composed of two or more propositions. There are
five types of these.
1. The copulative proposition is a
multiple categorical proposition which has two or
more subjects, or two or more predicates, or two or
more subjects and predicates. Examples: "Richard
Nixon and Gerald Ford were presidents of the United
States," "Peter is president and chairman of the
board of his company," "Jack and Jill went up the
hill and slid back down again."
Each of these sentences can be resolved into as
many single propositions as there are different
subjects and predicates. Examples: "Richard Nixon
was president," "Gerald Ford was president," "Peter
is president of his company," "Peter is chairman of
the board." The truth of copulative categoricals
depends on the truth of all the single sentences
which compose the multiple proposition.
2. The adversative proposition is a
multiple categorical proposition which consists of
two propositions united in opposition to each other
by conjunctions such as "but," "yet," "although."
Examples: "The dog was barking, but no one cared,"
"Jack lost his business, yet he was not depressed,"
"The woman bought a purse, although she did not
need one."
To be true, each sentence must be true, and the
opposition must be true. Example: It must be true
that "The dog was barking" and it must be true that
"no one cared."
3. The relative proposition is a multiple
categorical proposition which expresses a
relationship of time or place between two
sentences. Examples: "Before beginning to eat his
salad, he told me the secret," "After hurrying
home, Jack called Jane on the telephone."
In order to be true, the single statements must
be true and the relation of their sequence must be
true. It must be true, for instance, that Jack
called Jane on the telephone and it must be true
that he did it after hurrying home.
4. The causal proposition is a multiple
categorical proposition which combines two
statements in such a way that the one is given as
the reason or cause of the other. The words
"because" and "for" commonly appear in this type of
proposition. Examples: "The times are good, for
people have a lot of money to spend," "Jack is
happy, because he got elected class president."
The truth of the causal proposition depends on
the truth of each categorical proposition contained
in it and on the causal connection that is declared
to exist between them. It must be true that "Jack
is happy" and it must be true it is "because he got
elected class president."
5. The comparative proposition is a
multiple categorical proposition which compares the
relation between a subject and predicate with the
same relation between another subject and
predicate, and expresses the degree of this
relationship as being either less or equal or
greater. This may sound complicated, but it really
isn't.
Example: "As you live, so you shall die." Three
statements are actually contained in this
proposition. The first one is "Your life has a
certain character." The second one is "Your death
has a certain character." The third statement is
not as obvious but is implied, and states "The
character of your death is the same as the
character of your life." Now, that wasn't too hard,
was it? Let's consider another proposition.
Example: "Harry Truman was a greater president
than Richard Nixon was." Here again, we have three
statements. One, "The quality of Truman's
presidency was great." Two, "The quality of Nixon's
presidency was great." Three, "The quality of
Truman's presidency was the greater of the
two."
The truth of a comparative proposition depends
on the truth of the two separate sentences and on
the truth of the degree mentioned as existing
between them.
Covertly Multiple Categoricals
The covertly multiple categorical propositions
have the appearance of single propositions but are
really multiple. Their composition lies concealed
in some word and this needs an exposition to show
the multiple character of the proposition. This is
why these sentences are called exponibles (from
expressed). We can resolve these multiple
propositions into individual sentences called
exponents.
The truth of exponible propositions is
determined by looking at the exponents and the
logical connection between them. If any parts of an
exponible proposition are false, the entire
proposition is false. There are four types of
exponible propositions.
1. The exclusive proposition is a
multiple categorical proposition which contains
some word or words such as "only," "alone,"
"solely," or "none but," which indicates the
exclusion of any other predicate from this subject
or any other subject from this predicate.
Example: "Only the better students will go on
the field trip." This proposition may appear to be
a single categorical proposition but it is not.
This proposition can be resolved by means of a
copulative proposition, in which one sentence is
affirmative and the other is negative. It becomes
the proposition "The better students will go on the
field trip and no others will go on the field
trip." Now it is obvious it is indeed a multiple
categorical proposition.
Another example: "None but the brave will
receive medals of honor." This appears to be a
single categorical proposition. It can, however, be
resolved into the following: "The brave will
receive medals of honor and no others will receive
medals of honor." We can now see clearly that it is
really a multiple categorical proposition.
2. The exceptive exponible proposition is
a multiple categorical proposition which contains a
word such as "except" or "save," to indicate that a
portion of the extension of the predicate does not
apply to the subject, or a portion of the extension
of the subject does not apply to the predicate.
Example: "All the athletes except John won an
event in the tournament." The resolution of this is
not difficult. It becomes, "All athletes in the
tournament won an event, and John did not win an
event in the tournament." Clearly a multiple
categorical.
Another example: "All the animals save one were
killed in the fire at the zoo." Resolution: "One
animal was not killed in the fire at the zoo, and
all the other animals were killed." Again, clearly
a multiple categorical.
3. The reduplicative exponible
proposition is a multiple categorical proposition
which contains an expression which duplicates the
subject or predicate, giving it special emphasis,
such as "as such" or "as a," and implies the reason
or cause for the connection between subject and
predicate. Confused? Don't be. Examples will help
you understand this ponderous definition.
Example: "Man, as man, is endowed with free
will." This proposition can be resolved into: "Man
is endowed with free will, because he is man." Now
it appears as a multiple categorical proposition.
It is reduplicative because it "reduplicates"
itself, that is, the idea of "man" is intrinsically
joined with the idea of "free will." You can't have
one without the other.
A reduplicative proposition is true when both
the plain statement and the reduplicative
substatement are true.
4. The specificative exponible
proposition appears similar to the reduplicative
proposition but really is quite different. It is a
multiple categorical proposition which contains an
expression which duplicates the subject or
predicate, giving it special emphasis, such as "as
such" or "as a," but merely implies the time
element or condition of this connection.
Example: "Peter, as a student in high school,
took part in the debating society." The fact that
Peter is a student has nothing to do with his
participating in the debating society as a student.
The resolution of this proposition is: "Peter is a
student in high school," and "Peter took part in
the debating society."
Another example: "The professor, as a historian,
was a very easy grader." The fact that the
professor is a historian has nothing essential to
do with the fact that he is an easy grader. He
could have one characteristic without the other.
The resolution is: "The professor is a historian,"
and "The professor is an easy grader."
Specificative propositions are true when both
the plain statement and the substatement are
true.
This ends our discussion of single and multiple
categorical propositions. Just remember that
categorical propositions always make a clean-cut
assertion; they always affirm or deny the predicate
to the subject outright with no qualifications.
Hypothetical
Propositions
The Nature of Hypothetical
Propositions
How does the hypothetical proposition differ
from the categorical proposition? While the
categorical proposition makes a definite and
unqualified assertion, the hypothetical proposition
does not declare an unqualified affirmation or
denial. It expresses the dependence of one
affirmation or denial on another affirmation or
denial. There are three types of hypothetical
propositions.
The Types of Hypothetical
Propositions
The Conditional Hypothetical
Proposition
The conditional proposition is a hypothetical
proposition which expresses a relation in virtue of
which one proposition necessarily flows from the
other because a definite condition is verified or
not verified. Sometimes these are called the "if"
propositions.
Examples: "If the barometer falls, there will be
a storm." "If Peter is a good boy, he will be able
to go on the trip." "If I make a lot of money, then
I will be able to buy a mansion."
The part of the proposition containing the "if"
is called the "condition" or the "antecedent." The
other part is called the "conditioned" or the
"consequent." Notice there is a strict relation
expressed in a conditional hypothetical
proposition. The "antecedent" must be true before
the "consequent" can follow.
The truth of conditional hypothetical
propositions does not depend on the truth of the
statements taken by themselves or individually. The
truth depends on the relation between the
statements.
For example, take the proposition "If the
barometer falls, there will be a storm." We are not
asserting that the barometer is falling. We are not
asserting that a storm is coming. We are simply
saying that the coming of a storm is dependent on
low atmospheric pressure which is indicated by the
falling of the mercury in a barometer.
In a conditional hypothetical proposition, it is
the dependence of one idea on the other that is
affirmed or denied. The truth of the whole
statement rests on the truth of the dependence.
The Disjunctive Hypothetical
Proposition
The disjunctive hypothetical proposition is one
which contains an "either-or" statement, indicating
that the implied judgments cannot be true together
nor false together, but one must be true and the
other must be false.
Examples: "Either the sun or the earth moves in
an orbit." "An automobile is either in motion or at
rest."
This type of proposition should present no
difficulty.
The Conjunctive Hypothetical
Proposition
The conjunctive hypothetical proposition is one
which expresses a judgment that two alternative
assumptions are not or cannot be true at the same
time.
Examples: "An automobile cannot be in motion and
at rest at the same time." "A person cannot be a
saint or a sinner at the same time."
For the truth of such a proposition, it is
necessary that they be really irreconcilable at the
same time. If we can prove that they may be present
together, we would prove the statement to be
false.
NEXT - Part 6:
The Opposition of Propositions
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