Questions tagged [logic]
Questions pertaining to logical constructs
32
questions
34
votes
9
answers
69k
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 ...
- 2,277
23
votes
8
answers
33k
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 ...
- 349
7
votes
4
answers
2k
views
Ambiguity in Negation: "John did not come because of the rain"
John did not come because of the rain.
This sentence seems to allow the following two completely different interpretations.
John did not come. And the reason was the rain.
John came. But the reason ...
- 4,572
21
votes
10
answers
8k
views
Is "I believe x does not equal y" the same as "I don't believe x equals y"
Given x and y could be any phrase, do these phrases always mean the same thing? If not, what's the difference?
I believe x does not equal y
I don't believe x equals y
- 313
2
votes
3
answers
996
views
How do definitions of words imbue meaning? [closed]
How do definitions of words imbue meaning?
To give you a gist of what I try to discover, I'll define a collection of sets of words and show that their intersection contains all 'circular defined' ...
- 207
1
vote
1
answer
81
views
What's the word for using a general argument that upon inspection does not apply?
Examples, some are ridiculous:
Someone refuses to buy a lab grown diamond because 'all diamonds are blood diamonds'.
We cannot buy a sports car because 'the trunks of sports cars are too small', even ...
- 159
17
votes
5
answers
231k
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?
- 289
12
votes
10
answers
2k
views
Understanding the purported ambiguity in “Every boy didn’t run”
I am a computer science professional.
I am reading the book Natural Language Understanding by James Allen where he writes:
“Every boy didn’t run” which is ambiguous between the read...
- 223
8
votes
3
answers
7k
views
Difference between "not every" and "every ... is not"
I've always understood that you can order the words not and every (or similar words) in the following two ways to convey distinct logical meanings.
Every human is not a man. There is no human being ...
- 195
8
votes
5
answers
1k
views
Does this logical fallacy have a name? [duplicate]
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 ...
- 569
7
votes
3
answers
3k
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?
- 734
15
votes
6
answers
4k
views
Term for the "extreme-extension" version of a straw man fallacy?
Take the most obvious, unimpeachable statement imaginable:
Drinking water is good for humans.
I am looking for a word that describes the action of taking the argument, applying some unreasonable ...
- 2,945
14
votes
2
answers
36k
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" ...
- 1,307
11
votes
4
answers
1k
views
Does the word "and" always mean a logical (boolean) operation?
For a simple phrase like "macaroni and cheese" it's clear you want both macaroni and cheese, not one or the other. But as more and more words are added, I've noticed a tendency to begin to read "and" ...
- 295
10
votes
8
answers
15k
views
Word/phrase/idiom to describe avoiding answering a question by stating the question doesn't need to be asked
I run into this situation often in the office. I have a specific question to ask somebody and have chosen the person to ask it, but that person doesn't know the answer.
Instead of answering the ...
- 203
8
votes
6
answers
8k
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 ...
- 849
7
votes
5
answers
20k
views
Cut the lights on
This expression is commonly used in the southern United States from Oklahoma to Virginia, and is patently illogical, and yet fails to inspire any consternation or lack of semantic connection. On a ...
- 79
6
votes
4
answers
17k
views
Overuse of "however" in my scientific writing? [closed]
In scientific writing, I always feel the need to logically connect all my sentences to have a clear logical path between beginning and end of a paragraph, else it is just feels like a list of random ...
- 314
6
votes
2
answers
1k
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.
- 526
5
votes
4
answers
2k
views
Use of "and" and "or" in lists when intent is to dissallow all items
Sometimes it is unclear to me whether "or" or "and" should be used in a list. For example I have seen the following lease agreement:
The dwelling may not be used for illegal activities: including ...
- 2,878
4
votes
2
answers
2k
views
What fallacy is this? "Your argument is wrong/invalid because it's just an opinion."
I encounter this fallacy frequently in online discussions where an opponent completely disregards all of my premises and says my conclusion is invalid because it's an "opinion" and "not objective."
...
- 143
4
votes
3
answers
2k
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 think ...
- 1,085
3
votes
3
answers
644
views
How to succinctly and clearly connote the reverse of a statement
Here's a published example of a problem I come across frequently:
A cop is six times more likely to be shot by someone black than the opposite.
Let us assume that the writer meant to say:
...
- 1,320
3
votes
1
answer
684
views
Is there a contraction for non-exclusive or?
I find that often, in technical writing, I want to specify that or is non-exclusive: or ≠ xor; or = and/or.
(Stylistically, "and or" is terrible and gets tiresome quickly;)
As an example of the type ...
- 1,163
2
votes
1
answer
2k
views
“Periodically” – How to Use This?
So, I happen to be in the process of creating this research paper about a historic figure; I had used Google to search for a synonym of occasionally, and one of the words I stumbled across was “...
- 107
2
votes
1
answer
100
views
What is the difference between these two sentences? "If A is true, then B is true" and "Since A is true, B is true"
Consider the following two sentences:
If A is true, then we can conclude that B is true.
Since A is true, we can conclude that B is true.
I have two questions:
What is the difference ...
- 159
2
votes
5
answers
152
views
Short human descriptions for logic's AND, OR and NOT
In a user interface, we are offering the user to combine searches using either AND, OR or NOT
http://whatis.techtarget.com/definition/logic-gate-AND-OR-XOR-NOT-NAND-NOR-and-XNOR
We have little ...
- 131
1
vote
1
answer
910
views
Word that serves the purpose of "xor?" [closed]
In programming we have the term "xor gate" for when one of two things is allowed, but not both. That is, P XOR Q is true if and only if exactly one of them is true, false otherwise.
But English is ...
- 29
1
vote
4
answers
919
views
What English construction matches the Boolean condition of nand?
English language usage has some logical word pairs including:
Or | Nor
Either | Neither
With | Without
But there doesn't seem to be an opposition to the word "and". In computer engineering and ...
- 632
1
vote
4
answers
486
views
"As a [noun]" followed by mismatching subject
There is one particularly commonly used language construct that I find logically incorrect. However, as a non-native English speaker, I can't decide authoritatively on whether the usage is actually ...
- 113
0
votes
5
answers
4k
views
Is there a difference between "being selected" and "being pre-selected"?
I am reviewing a document where it is stated that something is part of a set of pre-selected items.
To me that doesn't make sense. Isn't everything selected also pre-selected by definition? I mean ...
- 790
-1
votes
10
answers
469
views
Boolean OR in English
What is the English equivalent of boolean-OR, which conveys the meaning of "either of the options or both", as opposed to XOR, which conveys the meaning of "strictly one or the other"?
"Either or ...
- 285