Does the phrase "Santa just isn't" make sense?

Question

As the title says, does it make sense?

It feels right. Not just though.

Answer 1

It makes perfect sense in context. The context is that it needs to be recognised as a sentence fragment. A fragment such as that is perfectly grammatical, though: it has a subject and a verb.

"I'm going to the party, but Santa isn't."
"Why isn't he?"
"He just isn't."

This can be said to be an extreme ellipsis, omitting the final "...going to the party."

As has been commented previously, the verb be can mean exist: "I think, therefore I am"; "To be or not to be, that is the question." But (a) this is now a specialised, particular use; (b) it doesn't really admit contractions.

I think, therefore I am; Santa is not.

Such a sentence is grammatical and complete, but because it relies on a particular sense of be it would benefit from some emphasis when spoken:

I think, therefore I am; Santa is not.

This particular usage might almost be punnish in the conversation above. Santa just isn't going to the party because he just is not.

Answer 2

It's ok as a sentence fragment but not as a whole sentence in itself.

"Santa just isn't very keen on mince pies."

is fine, but

"Santa just isn't."

as a way of saying that Santa doesn't exist, is not normal usage and is not likely to be understood without some kind of further context, explanation or parallel construction to clue the reader in to what it means.

If the phrase had some context, like this:

"I'm eating mince pies. Santa just isn't."

then that would be comprehensible, but only because there's an ellipsis - the context indicates what Santa isn't doing: "Santa just isn't eating mince pies".

You could also get away with it by using a parallel construction to explain in what sense you intend the reader to understand the verb 'to be':

"I think therefore I am, but Santa just isn't."

That's my instinctive feeling as a native speaker; it's a little difficult to find documentation to back this up (which is interesting in itself - I'm quite surprised that "it just is" just isn't in the OED).

But let's look at the relevant bit of the OED definition for 'be':

I. Without required complement: to have or take place in the world of fact, to exist, occur, happen.

1.

a. To have place in the objective universe or realm of fact, to exist; (spec. of God, etc.) to exist independently of other beings. Also: to exist in life, to live. Now literary.

Here's the citations, from Hamlet onwards:

• 1604 Shakespeare Hamlet iii. i. 58 To be, or not to be, that is the question.
• 1611 Bible (King James) Gen. v. 24 Enoch walked with God: and he was not; for God tooke him.
• 1697 Dryden tr. Virgil Æneis ii, in tr. Virgil Wks. 247 Troy is no more, and Ilium was a Town!
• 1733 Pope Ess. Man i. 115 To be, contents his natural desire.
• 1762 W. Falconer Shipwreck iii. 51 The parting Ship that instant is no more.
• 1810 Scott Lady of Lake iii. 97 How are they blotted from the things that be.
• 1823 Byron Don Juan: Canto IX xxiv. 17 Tyrants and Sycophants have been and are.
• 1827 T. Carlyle in Edinb. Rev. Oct. 347 God is, nay alone is.
• 1837 T. Carlyle French Revol. I. i. ii. 11 So much that was not is beginning to be.
• 1907 E. Nesbit Enchanted Castle xii. 347 The great beasts came first, strange forms that were when the world was new.
• 1961 Bible (New Eng.) John i. 1 When all things began, the Word already was.
• 2004 Independent 3 Mar. 10/1 After 58 years the BBC's Letter from America, the world's longest-running speech radio programme, is no more.

"be, v." OED Online. Oxford University Press, December 2014. Web. 29 January 2015.

I've highlighted the negative versions - none of them use the contracted form ('isn't') - although of course that in itself doesn't mean that you can't do it.

The nearest I can come to an explanation - or a justification, really - is that because this particular use of 'to be' is "now literary", the contraction just doesn't work with it. OED.I.1.a is a rather formal usage, and the contraction (being innately informal) can't co-exist with that.

This is also true of other uses of 'to be': the song title

"I Am What I Am"

could not be rephrased as

"I'm What I'm"

without losing its meaning, and

"I think therefore I am"

is not equivalent to

"I think therefore I'm".

Answer 3

(Without any padding such as suggested in other answers) it's an unusual construction, but as an intended parallel or anti-parallel of

I am

(KJV, God telling Moses His Name)

it makes a telling contrast. Some might consider it rather too blunt, offensively so perhaps. I doubt that anyone would suggest it was blasphemous.