5

It is the Fallacy of the undistributed middle: All Apples are Fruit All Oranges are Fruit Therefore, all Apples are Oranges is clearly invalid.


4

Celaront was not in the original Aristotle's list of valid syllogistic figures (or : moods). It was added later (during the Middles Ages ?) as one of the two subalternate moods in the first figure (Barbari and Celaront). If we agree (as Aristotle does) that every term has reference, from Cesare : No reptiles have fur. (MeP) All snakes are reptiles....


4

No, it is not. It is a valid argument : The premise : All teenagers are impulsive is equivalent to : for every x, if x is not impulsive, then x is not a teenager. Thus, using the second premise : John is not impulsive we can correctly conclude with : John is not a teenager.


3

Irving Copi calls propositions such as "James' son is a man" or "Socrates is mortal" singular propositions. They are nonstandard-form propositions. They need to be translated into standard form categorical propositions which relate classes before being used in categorical syllogisms. He recommends the following: (page 239) To every individual object there ...


3

The classical syllogisms consist of propositions which use only simple (ie, one "variable") terms in the subject and predicate, so any argument containing propositions which use complex terms isn't a valid (classical) form, although it can still be handled within term logic by extended inference rules. A complex term can be any Boolean expression. Being a ...


2

Harry J. Gensler begins his chapter, "Syllogistic Logic", as follows: Syllogistic logic studies arguments whose validity depends on "all," "no," "some," and similar notions. This branch of logic, which goes back to Aristotle, was the first to be developed. It provides a fine preliminary to modern symbolic logic, which we begin in the next chapter. ...


2

The answer is, "if your teacher requires it." Given how far logic has advanced, this assignment clearly falls in the realm of "history of logic." Even solving syllogisms themselves is largely a relic of earlier times. So you're unlikely to win this case by the argument that the rhyme is archaic and outdated, because the entire topic is.


2

John is not a teenager, since all teenagers are impulsive, and John is not impulsive. All teenagers are impulsive people. John is not an impulsive person. Thus: John is not a teenager. The form is AEE in the second figure (All P are M; No S are M; thus No S are P). The syllogism is valid. The middle term (impulsive people) is distributed in the minor ...


2

The problem seems to be more a linguistic than a logical one; in particular, the crucial phenomenon here is that of presupposition. In "James' son is a man", the possessive construction "James' son" can be seen as acting as a so-called definite description where one particular individual is identified by the description "that individual which is the son ...


2

Here is an excerpt from Russell's fifth lecture on Logical Atomism: "This notion, of course, of general propositions not involving existence is one which is not in the traditional doctrine of the syllogism. In the traditional doctrine of the syllogism, it was assumed that when you have such a statement as “All Greeks are men,” that implies that there are ...


1

From that passage alone, no. Merely to say that actions and passions are accompanied by pleasures and pains is merely to identify a correlation. However, if we look at BK I of the Nicomachean Ethics, then we have two details that at first glance sound like a hypothetical syllogism: The argument from the first part about intermediate and final ends and that ...


1

I believe that is the fallacy of undistributed middle. The middle or shared term or class, "fruit", remains undistributed in either premise. For a more complete discussion of this fallacy, you could take a look at this brief introduction.


1

| 1. P > (S v R) |_ 2. ~((~P v ~Q) v (R v ~L)] To conclude S from the first premise you need to derive P and ~R from the second. So, judging by your rule abbreviations , your proof should look somewhat like> | 3. ~(~P v ~Q) ^ ~(R v ~L) DM 2 De Morgan's | 4. ~(~P v ~Q) SIMP 3 Simplification | 5. ~~P ^ ~~Q ...


1

Here is a solution to compare with what you have. Also you might find the proof checker helpful to check the other proofs you are asked to do: For this proof checker DeM is De Morgan rule, ∧E is conjunction elimination, DNE is double negative elimination, →E is conditional elimination and DS is disjunctive syllogism. Kevin Klement's JavaScript/PHP Fitch-...


1

Is it not also the case that the minor term of a syllogism is the subject of the conclusion and the major term is the predicate of the conclusion? Yes. If so, then which of ‘A’ and ‘C’ is the major term and which is the minor term? It depends. Or does it depend on the form of the conclusion, such that ‘A’ is the minor term in the former [No ‘...


1

See Syllogism : Basic structure : A categorical syllogism consists of three parts: Major premise Minor premise Conclusion Each of the premises has one term in common with the conclusion: in a major premise, this is the major term (i.e., the predicate of the conclusion); in a minor premise, this is the minor term (i.e., ...


1

The term subalterantion explains why one can derive a particular proposition from a universal proposition. This can also be referred to as the dictum de omni et nullo. There is a wiki page on it that I cant apply here for some reason. Basically what can be denied of a whole must also apply to members of the whole simultaneously. We can't have exceptions ...


1

Both examples draw a particular conclusion (some... not) from two universal premises (all, none). Both syllogisms are valid, but are “weakened” forms because in each case the premises support the universal conclusion. The term “weakened” originated with medieval logicians, who “thought it pointless to get a particular conclusion when one could get the ...


1

Not all syllogisms produce understanding. For example, the syllogism All A is B. All B is C. ∴, all A is C doesn't tell us anything beyond rules of logic (formal logic); unless we know what A, B, and C signify (in which case the study of this syllogism would pertain to material logic). Premises of a syllogism are the efficient cause of its conclusion. ...


1

See Pr.An, Bk.I : It is first requisite to say what is the subject, concerning which, and why, the present treatise is undertaken, namely, that it is concerning demonstration, and for the sake of demonstrative science; we must afterwards define, what is a proposition, what a term, and what a syllogism, also what kind of syllogism is perfect, and what ...


1

You are tacitly assuming that if you want X, you ought to take the means to obtain X. Whether or not Hume would allow the premise, if you do allow it, then "I want X" is a claim about an ought (about a value rather than a fact), so therefore your whole syllogism adheres to Hume's principle: reason can't get you a conclusion about ought from premises about is....


1

Why does one negative premise suffice to imply a negative conclusion? One negative premise is sufficient to require a negative conclusion because of the distribution of terms in the premises. From the Capaldi and Smit book: If the conclusion is affirmative, there can be no negative premises. If there is a negative premise, there must be a negative ...


1

Everything is subject&predicate Well almost but not quite... Every sentence is subject&predicate Better but still not quite Every sentence in majority European languages is subject&predicate. The great linguist Whorf showed that an English statement like "The light flashed" has a bogus subject-predicate structure The Hopi equivalent is ...


1

The problem with Darapti is the existential fallacy. The reasoning uses two universal premises to reach a particular conclusion. From the site Logically Fallacious: A formal logical fallacy, which is committed when a categorical syllogism employs two universal premises (“all”) to arrive at a particular (“some”) conclusion. In a valid categorical ...


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