# Is there a conjunction bias?

This is slightly related to question The unprecedented success of the “intersection” operator .

Apart from a set of maths books of null measure, most have the following property:

Objects definitions are presented as a conjunction of properties.

Most axiomatic are also clearly conjunctive in their presentation.
It is uncommon to have say "By definition a Zorglub is a red zorg or a white zorg".

Q1 : Do you agree with the bias (if not, give enough examples)?.

Q2: Is this bias mainly a discourse convention or does it lie deeper (where?) ?

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We generally want to talk about very specific things; conjunctions increase specificity, and hence they're useful. Maybe I'm missing the point---are you asking for more than this sort of answer? – Scott Morrison Feb 16 '11 at 2:35
Conjunctivitis can be extremely contagious. – Tom Goodwillie Feb 16 '11 at 4:35
@Scott: Specificity is relative (level) . A 'human being' is a man of a woman ( Yet of course you could argue that the right name is 'social human being' and that is certainly less natural as a concept as it's longer name shows).Yes I ask for more but your idea is good as one of the reason for the bias, yet it look to me as not being the only one. – Jérôme JEAN-CHARLES Feb 16 '11 at 5:19
I don't think I agree with this bias- every time we say "by abuse of notation" we mean a disjunction. A common disjunction in mathematics would be define a zorg to be either a specific zorg or an equivalence class of zorgs, and similarly for maps between zorgs. For instance, a knot is a PL embedding of S^1 in S^3 or in R^3; or an ambient isotopy class thereof. – Daniel Moskovich Feb 16 '11 at 14:31
When I first saw this question, my impression was that it was too broad to get useful answers. But I wasn't sure, so I let it lie for a while to see what kind of answers would be given. Now, 14 hours later, the response I like best is Tom Goodwillie's conjunctivitis joke...so I have voted to close. – Pete L. Clark Feb 16 '11 at 16:26