7

This is one of those phrases used very commonly (and apparently subject to lots of scrutiny on this website), but is difficult to define and also far too long to submit to a reverse dictionary.

Let's say there's a situation with two outcomes. If outcome Y occurs, this means X must also have occurred. However, if we're only told that X occurred, we know nothing on whether outcome Y occurred or not.

The specific example for which I need this adjective is describing venom in spiders:

All spiders are venomous, but not all spiders have lethal enough venom to kill humans.

In this case, “lethal to humans” is outcome Y and "venomous" is X: if you're told that a spider is lethal to humans, you know that it must be venomous, but if you're told that the spider is venomous, you have no idea whether or not it can kill humans.

I can also word it as “Just because a spider is venomous, does not necessarily mean it kills humans.”

This "just because... doesn't necessarily mean..." phrase is used so often in common English that I'm convinced that there has to exist a one-shot adjective to describe the entire situation.

Following is a list of words that others have suggested that I think aren't accurate - if I was interpreting any of these incorrectly, please let me know.

  • mutually exclusive: would be correct if X and Y were traits that never occurred together
  • syllogism: describes a different logical scenario (3 statements: major, minor, conclusion)
  • modus ponens: only describes half of the relationship, the "Y implies X part"
  • prerequisite: only describes X, I want an adjective that describes X and Y's relationship
  • necessary and sufficient: only describes half of the relationship, the "Y implies X part," plus both words have different meanings in statistics and colloquial English
  • co-dependent: only has an irrelevant definition in psychology
  • converse implication: only describes Y, I want an adjective that describes X and Y's relationship
  • materially conditional: only describes half of the relationship, the "Y implies X" part

Question
What is the adjective?


TL;DR: "Individuals who value honesty above all tend to come off as insensitive to their peers, but just because I am honest does not necessarily mean I am insensitive. Thus, honesty and insensitivity are _____ traits."

What is the adjective that should fill in the blank?

3
  • Could you frame a sentence to describe the situation and leave a blank for the adjective? It will help us understand what you're looking for.
    – Tushar Raj
    Apr 12, 2015 at 12:04
  • I've added a TL;DR at the bottom. Hopefully that helps. @Area51DetectiveFiction Apr 28, 2015 at 5:08
  • "It does not follow [causally] that." Adjective would be "logically fallacious" or "illogical"
    – SAH
    Nov 1, 2016 at 20:57

5 Answers 5

5
+25

converse implication: only describes Y, I want an adjective that describes X and Y s 'relationship

The adjectives (concepts) you need are necessary and sufficient and the concept you already know of "relationship betweem X and Y (usually P and Q in logic), that is "implication"

In the quoted link you can see the possible combinations, the example you quote

The specific example for which I need this adjective is describing venom in spiders: "All spiders are venomous, but not all spiders have lethal enough venom to kill humans".

(not all spiders are venomous, so here you are already setting 2 conditions : X is a spider and X belongs to the subset of venomous spiders)

the condition P (a spider is venomous) is necessary but insufficient to Q (kill a man)

"just because an animal is a spider (and venomous spider) ... doesn't necessarily mean that it can kill a man”

1

How about "notwithstanding".

It's extremely toxic venom notwithstanding, the daddy-long-legs can't hurt you.

0

partial implication

or better

potential implication/inference ("venomous [spider]" might mean "deadly [for the man]")

come to mind in terms of the logical relationship.

2
  • @John Lawler Calling Professor Lawler to the rescue :-) Apr 5, 2015 at 4:38
  • Can you provide references? I searched all 3 phrases on dictionary.com, Merriam-Webster, Wiktionary, and Google and didn't get any useful results. Apr 6, 2015 at 6:02
0

I believe the fallacy is called Affirming the Consequent

http://en.m.wikipedia.org/wiki/Affirming_the_consequent

also called the converse fallacy.

As for an adjective that applies to X and Y's relationship, I would say they are not mutually implicative , because one implies the other, but the other does not imply the first.

But this is not saying much. If they were mutually implicative, they would form an identity ( X=Y) or a tautology (X=>Y AND Y=>X)

Or you could say one-way implicative, which, again, is not saying much; it says no more than X=>Y.

1
  • "Affirming the consequent" seems to be the scenario when I try to claim that Y is true knowing that X is (i.e. it's a derivative of the whole scenario). And, as you said, those adjectives don't suggest much. Apr 6, 2015 at 6:07
0

I believe this can be described as a conditional statement, or just as an adjective - conditional.

1
  • 2
    Hi Maddie, welcome to ELU! For the benefit of the OP, can you provide a reference source for that, and perhaps an example sentence or two?
    – Erich
    May 8, 2015 at 23:57

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge that you have read and understand our privacy policy and code of conduct.

Not the answer you're looking for? Browse other questions tagged or ask your own question.