"Supposably" vs. "Supposedly"

[Digital Stimulus]

I was taught "supposedly" is proper English and that "supposably" is not. Recently, I was challenged about it by my wife, who informed me that "supposably" is indeed in the dictionary. (I haven't performed anything approaching an exhaustive search, but it has been in every dictionary I've looked at so far.) I searched the archives here, and found some threads that mention it (with a reference to Joey Trebiani from Friends to boot!), but none that have contained any information as to *why* it's improper.

Certainly, one may suppose something. That something is then supposable. So, supposably, that something is correct. That makes sense to me, and yet I can't help but think it's wrong. (If one goes back and uses "believe" rather than "suppose", I'm less convinced it is incorrect.)

My question is - why is "supposably" improper English, based on grammatical rules or solid reasoning rather than simple dogma?

Thanks,

Kramer

[manhattan]

Welcome to the boards!

Your question is best suited to our General Questions forum -- I'll move it over there for you. Enjoy your stay!

[Zeldar]

If you check the definitions of those words (yes, it's in my dictionary, too) I think that context is going to be where the "supposedly" vs. "supposably" distinction comes in.

Most of the objections I hear to the use of "supposably" is as a synonym for "supposedly."

They don't appear to be synonyms.

[foolsguinea]

"Supposedly" means something is supposed.
"Supposably" (which I don't recall ever hearing) means something can be supposed.

I suppose that someone could want such a fine distinction as that which can be supposed but isn't, in which case "supposably" would seem to be the word to use. But if you mean that people suppose this to be true, you want "supposedly."

[Colibri]

Originally posted by jkramer3
My question is - why is "supposably" improper English, based on grammatical rules or solid reasoning rather than simple dogma?


Zeldar has it. There's nothing wrong grammatically with "supposably," it's that it's meaning is confused with "supposedly.

"Supposably" means "capable of being supposed."

"Supposedly" usually means "believed to be;" sometimed "mistakenly supposed," or "probable."

When people say supposably, what they usually mean is supposedly.

[Achernar]

Without contradicting anyone previous, here's my take. Roughly speaking, when modifying a predicate, supposably means "it seems to me that", while supposedly means "according to someone else".

Like say someone told you that a duck's quack doesn't echo in a vacuum.

No, wait, that's dumb. Imagine we're at a bus stop and I say, "Supposedly, this bus is never on time." You'd think I'd heard it from someone. But imagine I said, "Supposably, this bus is never on time." This would mean that I've seen the bus late a couple of times, and am comfortable in the assumption that it's always late.

[drhess]

Very good, Achernar! That's a great way of putting it.

[moriah]

A better distinction is past and future.

If something has been supposed (thought possible in the past, has been questioned as to its certainty in the past), then it is supposedly so.

If something can be supposed, then it is suposable (thought possible in the future, can be questioned as to its certainty in the future) and thereby, supposably so.

Peace
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The distinction between supposedly and supposably was supposedly one of person, but is supposably one of temporality.