Questions pertaining to logical constructs
-3
votes
2answers
53 views
“Only for A, B, and C”: Includes cases where not all are present? [closed]
After submitting the report, changes can be made only for the font
size, margins, and line spacing.
Does this sentence imply that changes can be made only if all three types of changes are ...
-1
votes
1answer
38 views
Responding with a basic fact to imply a point of view is clearly flawed or wrong
What is a word or concept that describes a situation where one person puts forth a point of view, and another person does not directly address the position, but instead responds with an obvious, basic ...
3
votes
2answers
107 views
Hypernym for “conjunction” and “disjunction”
Is there a hypernym for conjunction and disjunction, in their logical senses? Just using "junction" doesn't seem right to me.
-5
votes
1answer
87 views
Does the use of the word 'itself' defy logic? [closed]
In simple arithmetic the basic operations of addition, subtraction, multiplication and division are all binary.
That means you need two numbers, one on each side of the operation, for an expression ...
0
votes
1answer
28 views
Can “refute” be used with “that” clauses, and if so, what is the meaning?
I refute that A is B.
If this structure is ok, which of the following does it mean:
I argue that A is not B.
I argue against some other position (such as X is Y), by arguing that A is B.
5
votes
1answer
296 views
“Neither can live while the other survives”— does it make logical sense?
At the end of the fifth book of Harry Potter, "The Order of Phoenix", there is a prophecy concerning Harry Potter and Lord Voldemort:
The one with the power to vanquish the Dark Lord ( Lord ...
0
votes
1answer
146 views
Meaning of “either”: “not /A or B/” = “not /either A or B/”?
In a positive sentence, "either . . .or" is sometimes used to express an exclusive disjunction.
However, what happens when “either” is used in negation, as in sentence two below? Is the meaning the ...
15
votes
5answers
2k views
“All that is gold does not glitter”
"All that is gold does not glitter" is the first line of a poem from the Lord of the Rings and it's supposed to mean "not all gold glitters" but I'm struggling to see how this can be deduced.
If all ...
3
votes
2answers
138 views
What's the difference between “Not Completely True” and “Completely Not True”?
From what I understand, in second order propositional logic, ∀¬x and ¬∀x are equivalent statements. Apparently these are not equal. ¬∀x ≡ ∃¬x
However, rendered into the English language, consider ...
2
votes
2answers
108 views
And/or in total negation: “Some people are not able to interpret and/or analyze”
In the following sentence, the “and/or” seems odd in a case of total negation:
Evidently some people are not able to interpret and/or analyze at that deeper level.
Because the sentence says “are not ...
1
vote
2answers
87 views
Without, free from, lacking, etc.: Unambiguous total negation with “OR”?
In the following, “does not cause” seems to be clear negation, and total negation requires “or”, therefore:
The widget does not cause deformities or cracks
However, it is unclear to me whether ...
4
votes
2answers
306 views
Does the plural include the singular?
Does the plural include the singular? And if so, in what sort of cases?
This question has arisen because of the example sentence below.
Amendment shall be permitted only in cases of:
1. deletion ...
6
votes
1answer
110 views
Historical frequency of expression “and/or”: Corpus search
What is the historical frequency of the expression “and/or”?
I have a feeling that I almost never see it in older texts, but that it is has become exponentially common in the past five or ten years. ...
-3
votes
2answers
86 views
No possibilities are ruled out
Suppose that two binary (yes-no) qualities are being considered. Often (yes, actually!) I want to express that all four combinations are possible: yes-yes, yes-no, no-yes, no-no. Is there a concise ...
2
votes
2answers
269 views
Unambiguous Way of Stating a Biconditional in Plain English
I am having a hard time understanding this section in Wikipedia's article on Logical biconditionals:
Colloquial usage
One unambiguous way of stating a biconditional in plain English is of the ...
-1
votes
2answers
211 views
Double negations [duplicate]
Possible Duplicate:
Is there a rule about double negations that aren't meant as double negations (e.g. “We don't need no education”)?
Meaning of “you don't need no memory” and ...
0
votes
3answers
351 views
What is the opposite of modal?
Is there a word for the opposite of modal?
Particularly, is there a word for the opposite of modal in the logical sense of relating to the modality between propositions? In other words, is there a ...
2
votes
3answers
512 views
What does “an A/B metaphor” mean?
I wonder what "an A/B metaphor" means, for example, in the following quote from Wikipedia about formal language:
"In some applications, especially in logic, the alphabet is also known as the ...
1
vote
3answers
145 views
Can I express future action without the exclusion of former activity?
Consider the following scenario. Someone is hired for a job and is new to the career field. For instance, a new accountant.
After being an accountant for a very short period of time, and doing an ...
4
votes
2answers
149 views
Is there a term for it when you use an obviously false statement to highlight the falsity or absurdity of another?
For example, person A states something. Person B says "And pigs fly" to imply person A was wrong.
If there's no term for it, what could you call that that sounds smart?
0
votes
2answers
245 views
All X are Y. Then Some Y is X? [closed]
I have the following statement:
All the actors are girls. All the girls are beautiful.
The conclusions are given below:
Conclusions:
1)All the actors are beautiful.
2)Some girls are actors.
My ...
3
votes
5answers
564 views
The size of my confusion is “second to none”
Why "second to none" is being considered as "the best" instead of "the worst" (almost non existent)? To my understanding - "none" is "nonexistent", while "second to none" should be... well... almost ...
6
votes
5answers
872 views
Can I say “We don't must”, any alternative using a modal verb if I can't?
Let me explain. Suppose someone says "We must play a game now". I disagree, but only on that we have to do it.
I shouldn't answer "We must not" because I would be saying that the game is not to be ...
1
vote
2answers
229 views
Improper usage of “subsequently” in the latest Futurama episode?
In the latest Futurama episode, called Cold Warriors, the professor says the following:
The common cold died out 500 years ago and subsequently humanity lost all resistance to its ravages.
...
7
votes
1answer
1k views
Difference between “subsequently” and “consequently”?
When studying and reading course material in "softer" sciences that are descriptive the word "subsequently" appears in a way like "and subsequently" ...what does it mean, disctinct from "consequently" ...
5
votes
2answers
348 views
“There is no doubt this is arguably wrong”
This is from a review of something:
There is no doubt that the (product name) is arguably the best consumer (product category name) currently on the market.
I stopped for a while after reading ...
8
votes
4answers
2k views
“If” vs “Only if” vs “If and only if”
If I said:
Yell only if I fall.
Would the person have to yell once I fell?
Sources of confusion
Wikipedia
This
guy
4
votes
3answers
674 views
'Therefore' in an illogical logic sense
I have a co-worker that is always saying "Therefore, A B C" when the "A B C" isn't a conclusion from any sort of deductive reasoning. For example,
Me: ... thus, that's how it works.
Her: I ...
10
votes
6answers
1k views
Does 'some' necessarily imply 'not all'?
If some X's are Y's, does that imply that some X's are not Y's?
5
votes
6answers
469 views
Is there a common English phrase for the 'so absurd it must be true' logical fallacy?
There are various common (often Latin) phrases for various logic fallacies, such as post hoc ergo propter hoc, argumentum ad populum, slippery slope fallacy, etc. Is there a common phrase used to ...
3
votes
2answers
468 views
Usage of “if and only if” as a nontechnical term
The phrase "if and only if" (iff) is commonly used in the field of mathematics (⇔) and computer programming, as a conditional expression in classical (Boolean) logic.
Within that scope, it might not ...
5
votes
4answers
347 views
Does this logical fallacy have a name?
A phrase being used by the "news" media regarding the recent arrest of people in Columbus, NM is "firearms favored by the Mexican cartels", referring to their purchase of AK47s and other ...
11
votes
5answers
4k views
Does “either A or B ” preclude “both A and B”?
In mathematics, "A or B" includes "A and B".
Does "either" mean "A or B but not (A and B)" or does it include the possibility of "A and B"?
The context might be mathematics, formal logic or ordinary ...
7
votes
4answers
23k views
“Centered on” or “centered around”
I have often heard presenters talking about something centered around another thing, but it seems a bit illogical and hence improper to talk like this. Am I right about this?
4
votes
2answers
6k views
Can I use “therefore”, “so”, “hence” and “thus” interchangeably?
I was taught that, at least, 'therefore' and 'so' and can be used interchangeably, one being informal, the other formal. But, even when written, replacing 'so' with 'therefore' doesn't seem correct.
...
6
votes
6answers
672 views
The word 'not' often doesn't mean total negation in mathematical sense?
Consider the following conversations:
X1: I paid $10 for that hamburger.
Y1: That's not cheap!
X2: I pay $1 for broadband Internet access.
Y2: That's cheap!
X3: I paid $1 for a hot ...
5
votes
2answers
233 views
Is it true that
Is the following sentence grammatically incorrect?
Is it true that 1+1=2 ?
I know it is easier to say: Is 1+1=2 true?
