I’ve long pondered the opposite of must, meaning the obligation does not exist. It isn’t must not - that specifies the opposite obligation.

One might say I must go to work today but I don’t have to go to work tomorrow - an awkward circumlocution.

I’ve tried ‘I not must go..’ but that sounds clumsy, even though it puts not in the place you’d expect it, before the word it negates.

Comments?

I needn’t go.

Grant

[quote author=granthutchison link=board=grammar;num=1034956538;start=0#1 date=10/18/02 at 12:47:28]I needn’t go.

Grant

I’d say, I need not go.  Funny, it resonates with my (sometimes) reluctance to contract words that we saw in "haven’t" and "have not."

Hmm. I’ve always considered "must" and "need" to be synonimous, however, it is apparent that "must not" and "need not" are interpreted differently.

Might this be explained by "need"‘s need for "to"? (as in "I need to eat" being equivalent to "I need not eat")

Suddenly that makes a lot of sense to me. "I need to not eat" would be equivalent to "I must not eat." I don’t suppose one could "must" a noun. (Hence it’s an "auxiliary" verb and the whole distinction is starting to make a little more sense to me.)

Anybody have any thoughts on "must needs." (a construction I run into occassionally.) It seems to me that "must needs" becomes its own compound auxiliary verb. it also seems to me that its construction has dropped the normally requisite "to" in "needs to". (Makes me want to stick a hyphen in there.)

[quote author=seanmcox link=board=grammar;num=1034956538;start=0#3 date=10/18/02 at 22:25:18]Hmm. I’ve always considered "must" and "need" to be synonimous, however, it is apparent that "must not" and "need not" are interpreted differently.

Yes, as brynbaker says, "must not" is the reverse obligation of "must" - in "must not" the must keeps its sense of obligation, and the not reverses the sense of the following verb. But in "need not", the not reverses the need, removing the obligatoriness from the expression - it’s the equivalent of saying "I don’t need to".

Anybody have any thoughts on "must needs."

This is such a strikingly odd phrase that I can still remember exactly when I ran into it first: at the age of ten, reading Gulliver’s Travels (and who on earth decided that was a children’s book?); the Brobdingnag section, to be precise.
Looking at the progression of usages in the OED, it seems that this construction orginated in an old adverb, needs, implying necessity, which seemed to be able to loll around the whole sentence rather than sticking with the verb the way the auxilliary must does. A sample quotation (rendering into modern spelling from the 1493 original) goes: "Perceiving when an argument proceeds into his conclusion needs." (The modern equivalent, I think, would be "Perceiving when an argument necessarily leads to his conclusion.")
Then, for some reason, needs got itself entangled with must - more or less intensifying the meaning of must by duplicating it, leading to such very definite constructions as: "But needs perforce I must become content ..."
Finally must, the auxilliary verb, and needs, the adverb, seem to have settled together in the forms must needs and needs must, doing more or less the same job as "really must" does today.

Interestingly, the OED also describes the same formation with will: "He will needs go", which implies fixity of purpose - the will implying purposeful action, and the needs providing the fixity.

Grant

I’m glad I asked about that. I suppose then that I have a new (old) synonim for "necessarily". (However, I’m going to have to sit a ponder its usage for bit before I begin to feel comfortable with it.)

I just took a look at the etymology proffered by Merriam-Webster. M-W gives it as having come from a genitive for of the old word for "need." M-W also gives the definition as "of necessity" or "necessarily." I think I’ll try to keep the "of necessity" or "of need" definition in mind as they are obviously genitive constructions.

I fear I may start runing around with contructions like "must of need" rolling out my mouth. However, if I’m careful (which I’m often not) it does not of need have to be so. (it does not needs have to be so; it does not have to be so of need)

Yeah, I’m going to want to play around with that. Thanks. :D

[quote author=seanmcox link=board=grammar;num=1034956538;start=0#5 date=10/19/02 at 12:43:01]Yeah, I’m going to want to play around with that. Thanks. :D

Pleasure. It was nice for me to be reminded of perforce - I think I might start wheeling that one out myself, on occasion.

Grant

[quote author=granthutchison link=board=grammar;num=1034956538;start=0#1 date=10/18/02 at 12:47:28]I needn’t go.

... and the other posts:

Need is not synonymous with must. I think need is an internal requirement or obligation (e.g. food), must is an external obligation imposed by society or authority.

[quote author=brynbaker link=board=grammar;num=1034956538;start=0#7 date=10/20/02 at 05:16:42]Need is not synonymous with must. I think need is an internal requirement or obligation (e.g. food), must is an external obligation imposed by society or authority.

That’s the derivation, for sure, but current usage has blurred that to extinction. ("I need to get my tax return completed soon", "I must have that dress")
The OED is happy with the external imposition of a need to act: "To be under a necessity or obligation to do something."

Grant

[quote author=granthutchison link=board=grammar;num=1034956538;start=0#4 date=10/19/02 at 10:13:13]
Yes, as brynbaker says, "must not" is the reverse obligation of "must" - in "must not" the must keeps its sense of obligation, and the not reverses the sense of the following verb. But in "need not", the not reverses the need, removing the obligatoriness from the expression - it’s the equivalent of saying "I don’t need to".

This has been a very interesting thread.  If I understand correctly:
I must go = I have an obligation to go
I must not go =  I have an obligation to not go
I need to go= I have an (internal) requirement to go
I need not go= I have no requirement to go

So the "not" in the "must" phrase modifies the "go," not the "must," but it does modify the "need" in the "need" case.

I suppose we’d have:
I must go= I need to go
I need not go= ?
I need to not go= I have a requirement to not go= I must not go.

But must and need are two different parts of speech: and auxiliary verb and an adverb, respectively.  A negator (sorry, I don’t know the grammatical term) in a sentence with must will negate the verb itself, but in a sentence with "need" negates the adverb, so long as they are attached.  

Is this quality due perhaps to the parts of speech, rather than the source in obligation of "must" and need?"

[quote author=tamisaac link=board=grammar;num=1034956538;start=0#9 date=10/20/02 at 12:23:26]But must and need are two different parts of speech: and auxiliary verb and an adverb, respectively.

The AHD finds that ‘need’ can be an auxiliary verb, and indicates an internal requirement or an obligation:

need
n.
1. A condition or situation in which something is required or wanted: crops in need of water; a need for affection.
2. Something required or wanted; a requisite: "Those of us who led the charge for these women’s issues ... shared a common vision in the needs of women" (Olympia Snowe).
3. Necessity; obligation: There is no need for you to go.
4. A condition of poverty or misfortune: The family is in dire need.

v.
need·ed, need·ing, needs
v. aux.
To be under the necessity of or the obligation to: They need not come.

v. tr.
To have need of; require: The family needs money. See Synonyms at lack.

v. intr.
1. To be in need or want.
2. To be necessary.

v. aux.
To be under the necessity of or the obligation to: They need not come.

It also provides interesting usage and regional notes:

Usage Note: Depending on the sense, the verb need behaves sometimes like an auxiliary verb (such as can or may) and sometimes like a main verb (such as want or try). When used as a main verb, need agrees with its subject, takes to before the verb following it, and combines with do in questions, negations, and certain other constructions: He needs to go. Does he need to go so soon? He doesn’t need to go. When used as an auxiliary verb, need does not agree with its subject, does not take to before the verb following it, and does not combine with do: He needn’t go. Need he go so soon? The auxiliary forms of need are used primarily in present-tense questions, negations, and conditional clauses. Unlike can and may, auxiliary need has no form for the past tense like could and might.

Regional Note: When need is used as the main verb, it can be followed by a present participle, as in The car needs washing, or by to be plus a past participle, as in The car needs to be washed. However, in some areas of the United States, especially western Pennsylvania and eastern Ohio, many speakers omit to be and use just the past participle form, as in The car needs washed. This use of need with past participles is slightly more common in the British Isles, being particularly prevalent in Scotland.

The AHD suggests that use of ‘must’ implies an external condition:

must
v.  v. aux.

1. To be obliged or required by morality, law, or custom: Citizens must register in order to vote.
2. To be compelled, as by a physical necessity or requirement: Plants must have oxygen in order to live.  
3. Used to express a command or admonition: You must not go there alone. You simply must be careful.  
4. To be determined to; have as a fixed resolve: If you must leave, do it quietly.  
5.  a. Used to indicate inevitability or certainty: We all must die.  b. Used to indicate logical probability or presumptive certainty: If the lights were on, they must have been at home.  

v. intr. Archaic
To be required or obliged to go: "I must from hence" (Shakespeare).

n.  
Something that is absolutely required or indispensable: Promptness on the job is a must. Comfortable boots are a must when going on a hike.  

[quote author=Agoraphile link=board=grammar;num=1034956538;start=0#10 date=10/20/02 at 14:22:16]The AHD finds that ‘need’ can be an auxiliary verb, and indicates an internal requirement or an obligation:

But, and precisely my point, their definition of need as an auxiliary verb has no connotation of "internal requirement":

To be under the necessity of or the obligation to: They need not come.

The illustrative example pretty much provides the sense that Bryn was looking for in his original post. This is very similar to what I found in the OED, that the "neediness" apparently drops out of the meaning of "need" when it’s used as an auxiliary.

Grant

[quote author=tamisaac link=board=grammar;num=1034956538;start=0#9 date=10/20/02 at 12:23:26]But must and need are two different parts of speech: an auxiliary verb and an adverb, respectively.

As Agoraphile’s post shows, I think need is appearing as an auxiliary verb in the construction "need not go" - the adverbial use I mentioned was a very antique construction involving "needs" that is still with us in "needs must" and not much else.

Grant

I’m interested in this antique usage of "must" meaning "to be obliged to go." I can see how this would translate into an "external" requirement. In just about any situation I can think of, one could simply replace the word "must" with the phrase "to be obliged to go." (with "to be" being conjugated appropriately of course)

I must get this done. = I am obliged to go get this done.

The whole external/internal thing had me confused for a bit, but I think I see how that works. (Obviously Grant is right that modern usage pretty much ignores the distinction.)

Does the AHD give a PIE root for must? (I am so very fond of that Indo-European appendix. Gotta get myself an AHD once I have a good grasp of the state of my finances.)

Does the AHD give a PIE root for must? (I am so very fond of that Indo-European appendix. Gotta get myself an AHD once I have a good grasp of the state of my finances.)

You need an AHD, or you must have one?  :)

You can always follow my rule of thumb as regards finances:  if you have cheques left you still have money in the bank.

[quote author=seanmcox link=board=grammar;num=1034956538;start=0#13 date=10/22/02 at 01:17:40]Does the AHD give a PIE root for must? (I am so very fond of that Indo-European appendix. Gotta get myself an AHD once I have a good grasp of the state of my finances.)

The AHD gives a long semantic trail:

Must

(from) Middle English moste, from Old English moste, past tense of motan, to be allowed; see med- in Indo-European roots.

PIE
med- To take appropriate measures. Derivatives include medicine, modest, modern, commodity, and empty.  

1.  

a. METE, from Old English metan, to measure (out), from Germanic *metan; b. MEET, from Old English gemaete, "commensurate," fit (ge-, with; see kom), from Germanic derivative *maeto, measure.  

2.  

a. MEDICAL, MEDICATE, MEDICINE, MEDICO; METHEGLIN, REMEDY, from Latin mederi, to look after, heal, cure; b. MEDITATE, from Latin meditari, to think about, consider, reflect.  

3. Suffixed form *med-es-.

a. MODEST; IMMODEST, from Latin modestus, "keeping to the appropriate measure," moderate; b. MODERATE; IMMODERATE, from Latin moderari, "to keep within measure," to moderate, control. Both a and b from Latin *modes-, replacing *medes- by influence of modus (see 5 below).  

4. MEDUSA, from Greek medein, to rule (feminine participle medousa < *med-ont-ya).  
5. Suffixed o-grade form *mod-o-. MODAL, MODE, MODEL, MODERN, MODICUM, MODIFY, MODULATE, MODULE, MODULUS, MOLD, MOOD, MOULAGE; ACCOMODATE, COMMODE, COMMODIOUS, COMMODITY, from Latin modus, measure, size, limit, manner, harmony, melody.  
6. Suffixed o-grade form *mod-yo-. MODIOLUS, MUTCHKIN, from Latin modius, a measure of grain.  
7. Possibly lengthened o-grade form *mod-.

a. MOTE, MUST, from Old English motan, to have occasion, to be permitted or obliged; b. EMPTY, from Old English aemetta, rest, leisure, from Germanic compound *e-mot-ja- (prefix *e-, meaning uncertain, from Indo-European *e, *o, to). Both a and b from Germanic *mot-, ability, leisure.  

The above is cut-and-pasted from my new electronic AHD, purchased for a mere $30 and downloaded from the yDc website.