# can, need, must



## Scholiast

Dear all

A sage moderator has asked me to re-post this here, rather than in the English Only forum where I first tried:

There must be previous threads on this, but I have been unable to find them.

One of the rare relics in modern English of the A-S conjugational system  is that of the 3rd-person singular of regular verbs ("she earn*s*...", "he show*s*" &c.).

Why do then these modal verbs (and others, such as "will") defy the  general principle? And why does "need" need "needs" when it is positive  ("He needs to go...") and not when not ("He need not go...")?

Σ


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## sumelic

Greetings Scholiast!
There's a good wikipedia article on it at http://en.wikipedia.org/wiki/English_modal_verbs. Basically, for most of the verbs used as modal verbs in modern English, the present tense actually descends from the Proto-Indo-European form that became the preterite for other verbs. These verbs are called preterite-presents because they have the form of preterites but the meaning of present tense verbs. And in preterite forms, modern English has lost all person-marking, so we don't see the -s suffix on the third person singular. "Need" is not a preterite-present verb; I guess that the "s" was dropped either by analogy with words of similar meaning like "must" and "should", or that some kind of subjunctive thing was going on.
Actually, some of the modern English modals are not descended from the original forms preterite-present verbs, but from the new past forms that arose in Germanic with dental past suffixes. It seems like there's been a general pattern in the history of English of past-tense forms being used sometimes not to denote literal past tense, but a more metaphorical distance from what is real. Words like "should", "would", "could", "might" are clearly the past forms of "shall", "will", "can" and "may", and "must" and "ought to" used to be the past forms of "mote" and "owe".


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## N'importe-qui

It's possible that "need" doesn't have the "s" because it continues the subjunctive. Additionally, other auxiliaries retain the "s" (is, has), so I'm not convinced that analogy is the most solid explanation.


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## fdb

sumelic said:


> descends from the Proto-Indo-European form that became the preterite for other verbs.



In other words: the IE perfect. You have perfect-presents in Latin too, e.g. odi.


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## N'importe-qui

fdb said:


> In other words: the IE perfect. You have perfect-presents in Latin too, e.g. odi.


It's not a good idea to think of the IE aspect as "perfect". Modern PIE interpretations refer to it as stative, expressing aspectless state of being or activity. Theoretically, it could have had tenses, but didn't seem to express any and so was probably generally present in meaning. In later development, it took on the connotation of present state achieved as the result of a prior action, and this is how the Greek perfect often tends to work. From there, it developed into a regular perfect and thence to a simple preterite, notably in Germanic. It's important to note that it's hard to explain the preterite-presents in Germanic and the perfect-presents of Latin without the stative interpretation. It's harder to explain how a true perfect tense could come to have a present meaning, than to explain that some verbs retained the stative form as is with present meaning and others used it for the past via the above-mentioned development in semantics.


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## Gavril

N'importe-qui said:


> It's not a good idea to think of the IE aspect as "perfect". Modern PIE interpretations refer to it as stative, expressing aspectless state of being or activity. Theoretically, it could have had tenses, but didn't seem to express any and so was probably generally present in meaning. In later development, it took on the connotation of present state achieved as the result of a prior action, and this is how the Greek perfect often tends to work. From there, it developed into a regular perfect and thence to a simple preterite, notably in Germanic. It's important to note that it's hard to explain the preterite-presents in Germanic and the perfect-presents of Latin without the stative interpretation. It's harder to explain how a true perfect tense could come to have a present meaning, than to explain that some verbs retained the stative form as is with present meaning and others used it for the past via the above-mentioned development in semantics.



This might be a side-issue, but are we sure that _can_/_shall_/_may_/etc. are a continuation of the stative semantics of IE perfects, rather than an internal Germanic development?

In modern-day English, the word *could* seems to have developed from being a simple past-tense form ("was able to") to a word with more conditional/subjunctive semantics ("might be able to"), and the word *might* has developed from the meaning "was able/permitted to" to the meaning "might be able/permitted to". Is it possible that the development of _can_/_may_/_shall_/etc. in early Germanic is just an earlier iteration of the same process?

(Then again, I don't know the specific details of how _could_/_would_/_might_/etc. have developed their subjunctive meanings: maybe the conditions for this development were not present in early Germanic.)


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## N'importe-qui

Gavril said:


> This might be a side-issue, but are we sure that _can_/_shall_/_may_/etc. are a continuation of the stative semantics of IE perfects, rather than an internal Germanic development?


Naturally, we can't be totally sure, as the development occurred before any attested Germanic language. That said, the semantics of many of the preterite-present verbs is stative, rather than modal. Notably, "fear", "owe", "learn", "be able to" are hard to categorize as anything other than stative.



> In modern-day English, the word *could* seems to have developed from being a simple past-tense form ("was able to") to a word with more conditional/subjunctive semantics ("might be able to"), and the word *might* has developed from the meaning "was able/permitted to" to the meaning "might be able/permitted to". Is it possible that the development of _can_/_may_/_shall_/etc. in early Germanic is just an earlier iteration of the same process?
> 
> (Then again, I don't know the specific details of how _could_/_would_/_might_/etc. have developed their subjunctive meanings: maybe the conditions for this development were not present in early Germanic.)


I think you're confusing later developments with the original state of affairs. Even in Modern English, we have the present "can", which is not at all subjunctive and expresses a stative idea. Since so few of these verbs remain as such in Modern English, it's hard to make definitive statements about their development just by looking at the current situation.

Remember also that "could", "should", "must" and "might" may actually just be continuations of the past subjunctive, which was even in Old English more or less equivalent in form with the past indicative for weak verbs. In German, where the subjunctive was more often marked by umlaut, the distinction is clear ("koennte" vs. "konnte" -- "I could" vs. "I was able").


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## berndf

Gavril said:


> This might be a side-issue, but are we sure that _can_/_shall_/_may_/etc. are a continuation of the stative semantics of IE perfects, rather than an internal Germanic development?


A mixture of both.
The present tense forms are morphologially regular class III strong verb preterite forms which makes the hypothesis of a derivation from the PIE stative quite compelling: _cunnan - ic can - þu canst - he can - we, ge, hie cannon_.
The past tense forms follow weak paradigms, i.e. they are obviously later additions within Proto-Germanic.


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## N'importe-qui

berndf said:


> A mixture of both.
> The present tense forms are morphologially regular class III strong verb preterite forms which makes the hypothesis of a derivation from the PIE stative quite compelling: _cunnan - ic can - þu canst - he can - we, ge, hie cannon_.
> The past tense forms follow weak paradigms, i.e. they are obviously later additions within Proto-Germanic.


But it's not just that the present tenses are formally equivalent to strong verb preterites (not all are class III, by the way, and at least one or two follow no identifiable ablaut pattern of strong verbs). The meaning of the present tense forms of these verbs in older Germanic languages is stative and, at least, not at all modal.


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## berndf

N'importe-qui said:


> But it's not just that the present tenses are formally equivalent to strong verb preterites (not all are class III, by the way, and at least one or two follow no identifiable ablaut pattern of strong verbs). The meaning of the present tense forms of these verbs in older Germanic languages is stative and, at least, not at all modal.


Gavril is right, "meaning" is something fuzzy and based on subjective interpretation and, as he said, you couldn't tell, if it is a intra-Germanic development or if it is really an inherited PIE aspect.

You need an analysis based on morphological paradigms as well to give the theory a decently solid base.


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## N'importe-qui

berndf said:


> Gavril is right, "meaning" is something fuzzy and based on subjective interpretation


I think you'd have to do some serious intellectual juggling to insist that "know", "fear" or "be able to" were really past tense forms that have somehow acquired a present meaning. It would certainly be an extraordinary claim to make, one for which you'd need considerably more evidence, and evidence that contradicts what we already have.



> and, as he said, you couldn't tell, if it is a intra-Germanic development or if it is really an inherited PIE aspect.
> 
> You need an analysis based on morphological paradigms as well to give the theory a decently solid base.


We have an analysis based on morphological paradigms. The preterite-present verbs are very consistent reflexes of the PIE perfect/stative formation. In fact, they retain some archaisms, such as the "t" of the 2nd person singular, otherwise lost in all Germanic languages except Gothic, and ablaut patterns that do not follow the existing strong verb patterns. Some of them also correspond directly with perfect-presents in Latin and Greek, the main example being "wait" and "oida". Same form, same meaning, same disconnect from the normal present/perfect distinctions in their respective languages.

If the question is whether the PIE perfect was actually stative, and not just a perfect with incidental stative meaning, there seems to be good evidence from older Greek and Sanskrit that verbs in this form had generally only stative meaning and only acquired the present perfect meaning at a later date. I know very little about Sanskrit, and only some about Homeric and other early types of Greek, so I can only repeat this as information I've read. Nonetheless, what I've seen seems convincing.


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## Gavril

N'importe-qui said:


> Remember also that "could", "should", "must" and "might" may actually  just be continuations of the past subjunctive, which was even in Old  English more or less equivalent in form with the past indicative for  weak verbs. In German, where the subjunctive was more often marked by  umlaut, the distinction is clear ("koennte" vs. "konnte" -- "I could"  vs. "I was able").



True, it seems (according to verbix.com) that these Old English verbs only  distinguished past subjunctive and past indicative in some of the  personal suffixes, which have long since been lost (indicative plural _cúþon_ "could" vs. subjunctive plural _cúþen_), and maybe it was only with the loss of these suffixes that the conditional and past-tense meanings merged in the same word.

I  still wonder, though, if meanings such as "to be able" and "to have to"  are expressed through the perfect in any IE languages outside Germanic?  I know that e.g. Greek can use perfect forms to express "know" and  "fear" (and perhaps also "own"), but as far as I know, the present stem  was used for "to be able" (_dúnamai_) and "to have to" (_deî_, _khrêi_, etc.).


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## fdb

Gavril said:


> I  still wonder, though, if meanings such as "to be able" and "to have to"  are expressed through the perfect in any IE languages outside Germanic?



As I am sure you know, können/can and kennen/know belong to the same Germanic root; “he can” is basically “he knows how to”. A semantic (not etymological) parallel is furnished by the perfect-presents Greek οἶδα_, _Sanskrit veda “I know”. Please note that Greek and Sanskrit have distinct forms for imperfect, aorist and perfect. These words are morphologically perfect.


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## Gavril

fdb said:


> As I am sure you know, können/can and kennen/know belong to the same Germanic root; “he can” is basically “he knows how to”.



That may be true of _can_'s Germanic cognates; in English, _he can_ also means "he is physically/mentally capable of (doing something)".

My understanding (maybe incorrect) is that, roughly speaking, Greek _dúnamai_ = "to be capable of", _epístamai_ = "to know how to", _oîda_ = "to know (a fact)". But each verb might be able to overlap with the others in some contexts.


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## berndf

The root split into two different verbs later, _can_ and _ken_, with different meanings. But the root is what fdb said.


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