I am sure that between “I know whom he is” and “I know who he is” the second is the grammatically correct, but for some reason I have difficulty explaining the reason for this to my mind. 
Is it something such as the word “that” being removed: “I know (that) he is who” as “I know (that) who he is”?
No, it’s because we do not reverse the order for the embedded question.
Where is he? - I know where he is.
Who is he? - I know who he is.
This is an embedded question. “Who” must be in the subjective case, although the question is not reversed (is he) but rather in the normal order (he is).
Sorry, in my question I meant to say:
Is it something such as the word “that” being removed: “I know (that) he is who” as “I know (that) who he is”? (not “who is he”!)
I know it should be “who”. I am just trying to understand why it is “who” instead of “whom” in this case.
Can we say it is who because it is the subject of the verb is? We do not say, for example, we saw the guy whom did it.
Paul
But why isn’t “who” the object of “know” when we say “I know who he is”?
Should we consider a “whom” as being implied instead, so that in meaning it is “I know whom who he is” but written as “I know who he is”?
Hi Essorant,
it seems to me that the whole clause ‘who he is’ is the object of ‘know’, not merely the word ‘who’. Within the object-clause however, the word ‘who’ is the subject, and therefore in nominative, not accusative case.
Does that make sense?
Maybe this little line of medieval Latin can help you.
Caedite eos! Novit enim Dominus qui sunt eius.
Classical authors, I think, would have preferred something like “Novit enim Dominus quos esse suos.” However, if you wish to use a finite form of the verb, you must have a subject that agrees with it.
The reason is this:
“who he is” is a clause that you will agree sounds correct. For example, “Who he is astounds me!” “Who he is makes everyone tremble,” etc. Therefore, “Who he is, I know him.” Thus: “I know who he is.” In reality, what has been omitted is the word “him” : “I know him who he is.” So “him” is the missing object you’re looking for, and its objectivity is transferred fully upon the clause “who he is,” though it shows no accusative marker.
Make sense?
It’s comparable to how Latin will omitt “is” in sentences like, “Is qui in lectica portatur multam pecuniam habet,” into “Qui in lectia portatur multam pecuniam habet.”
Do you have any sources you could refer to for this Luce? English is admittedly only my second language, but i don’t see any need to imply the word ‘him’, or assume that it has been omitted, particularly ‘in reality’. It seems to me that English simply does not require such a word to be expressed or implied, because the clause as object itself suffices.
Afterall, contrary to popular belief, English is not Latin in code.
Of course, i’d happily be wrong.
Hi Kasper; I had no idea that English was your second language; what’s your first, if I may ask?
Have you read the King James English version of the Bible? In it you’ll read many unmodern forms of English, that still fully qualify as Modern English and are officially part of this very language (including “thou” and “thy,” inter alia). Constructions such as, “They saw him who was fortold,” and so forth, are much more common. Though the hodiern English eschews these redundancies, they used to be quite normal.
So indeed, in reality, this is the omission, of the word “him.” I agree with you fully that the English of today, and of yesterday, does not require this “him,” and leaves it implicit — it even sounds strange to our ears of today. Still, this is the form, and I defer to someone else with more experience in explaining these constructions to provide more appropriate terminology and examples. After all, I learned about this concept here, at Textkit.
This is like déjà vu all over again (almost to the day one year ago).
No, I already told you. The fact that it is an embedded question is the REASON. There is no relative pronoun left out. It is not “I know that he is who” which becomes “I know who he is.” Just look at other embedded questions and you will see that it only makes sense!
What does he want? > I don’t know what he wants.
Whom will he bring? > I don’t know whom he’ll bring. (grammatically correct, though not colloquial)
Who will be there? > I don’t know who will be there.
Where has he been? > I don’t know where he has been.
How did he get there? > I don’t know how he got there.
Why did you say that? > I don’t know why you said that.
The question word is attached to the QUESTION. It is not a connector or relative clause opener. It is simply a QUESTION WORD! So, it functions in the same way that it would if you didn’t have the introductory phrase, which makes the question both indirect and embedded.
I agree with jaihare that it’s just a matter of being an indirect question, and the question word never changes when you go from direct to indirect. Also, I don’t think “who” is the subject of “who is he?”. Compare “who are you?” where the verb agrees with “you”, and how “he” moves back in front of the verb to subject position in the indirect question like with “I know who he is” but on the other hand you have “who’s here?” > “I know who’s here”.
Indeed. Because in “who is he?” the “who” functions as the predicate nominative in question.
He is John.
He is ?.
Who is he?
The subject is still “he.”
He is at work.
He is ?.
Where is he?
You’re right on the money. The difference in the last sentence is that “who” is the subject there.
John is there.
? is there.
Who is there?
I always tell my students that English grammar’s mostly systematic and easy, but sometimes I think I’m just plain wrong. LOL
Me liketh Lucus’ explanation best. It makes most sense to me to to think of the object as being invisible.
But I admit I am so obstinate that I still think that “whom” may be better in this case. That is is because the object itself is meant refer to a questionable being (a who), not a specific person with indication of gender (a him). I think this may be seen a bit better in a saying such as “she is who I love”. It doesn’t seem correct to decipher that as “she is who (her) I love”. But similar to the saying “It is that that I love” with two that’s, one going with “is” and the other being the object of “love”, it seems like sayings such as these have two who’s, where the one that is the object (the whom) is invisible.
I know who he is = I know (whom) who he is.
She is who I love = she is who (whom) I love
The subject “who” is seen by the eye. But the object “whom” is invisible and playing the ghost.
Certainly you can see that these two sentences are VERY different.
He is ?. (PREDICATE NOMINATIVE OF EQUATIVE VERB)
I know who he is. (Both GRAMMATICAL and COLLOQUIAL)
*I know whom he is. (Neither grammatical nor colloquial)
I love ?. (OBJECT OF THE VERB LOVE)
She is whom I love. (GRAMMATICALLY CORRECT, though not colloquial)
She is who I love. (Colloquial because we would now ask “Who do you love?” rather than “Whom do you love?” despite its being ungrammatical)
The two cases are different. The first case has to be the subjective case (who) while the second should grammatically be in the objective case (whom). Really, I don’t see what the confusion is here. The syntax is quite obvious.
Certainly you can see that these two sentences are VERY different.
VERY different?
They are the same kind, just with a different wordorder!
Um. Ok. SInce you told me…
With that said, your reasons sound sound.
But, what about the following sentence: I have always known him to be a stand up guy. Him is the Objective case. Colloquial?
Sure. It’s Dutch.