Is “else” in “someone else” necessary?

Question

Since I'm already referring to a person in third-person by using "someone", isn't the "else" in "someone else" redundant? If it not, why is that? The only significance I see in the addition of "else" is the implication that a person other than myself is similar to me, so "else" is just indicative of equality.

Context:

The man wants to be like someone else.

More context:

Someone else created that control mechanism.

Some more context:

When someone else wants to complete that task, they'll get it done.

In all cases, I feel like taking "else" away allows the meaning of the sentence remain.

Answer 1

The else is being used to highlight that you are referring to someone other than an implied or previously mentioned person.

Your three sentences really require more context and would be used something like this (just for example):

The man was not happy with his personality. The man wants to be like someone else.

The man wants to be like someone other than himself.

— Did you write that control software? — Someone else created that control mechanism.

It was someone other than the person being asked who created the control mechanism.

Bob is a very lazy man. When someone else wants to complete that task, they'll get it done.

Someone who isn't lazy would get the task done. [Apologies to all Bobs.]

Answer 2

...so "else" is just indicative of equality.

No, indeed it could well be suggestive of inequality.

It's indicative of difference, "someone else" is not the person or people currently referred to.

The man wants to be like someone.

Could make sense if we take "someone" to imply "someone of importance", much as somebody is used in "You don't understand I could've had class, I coulda been a contender, I could've been somebody... instead of a bum which is what I am, let's face it." from On the Waterfront (and indeed the scene in Raging Bull where he quotes On the Waterfront). This though is a different sense of someone to how it's used with the else; in the same sense he already is someone, so we need the else to get the real sense of the statement.

Someone created that control mechanism.

This is now close to a non-statement; of course someone created it. "Someone else created it" tells us that it was not created by the person/people/company who are the current focus of discussion (if there was no such focus, then it would mean someone else other than the person making that statement).

Because difference allows for inequality, then contrary to your statement about equality, it could be used to reflect inequality. (Inequality entails non-identity [not being the same thing or person] but non-identity does not entail inequality):

Maybe someone else can understand this.

Suggests that someone else might have the knowledge or deductive ability needed, but the speaker does not, so that "someone else" is not equal to the speaker, they're superior in this particular quality.

Conversely:

Maybe someone else would do that, but I couldn't do so in good conscience.

Suggests that the hypothetical someone else is morally inferior to the speaker, or at least would make the moral decision on different grounds.

Answer 3

1a The man wants to be like someone
1b The man wants to be like someone else

1a is either a silly statement or it's the introduction to "Who does he want to be like?", which implies that the speaker and listener are playing a guessing game. It would be better expressed as a single sentence: "Who does the man want to be like?"
1b is the response to someone's incorrect answer to the question in the previous sentence. The else is required for this sentence.

2a Someone created that control mechanism
2b Someone else created that control mechanism

2a is merely a statement of the obvious, unless the speaker or listener or both believe that control mechanisms create themselves or are spontaneously generated in some other mysterious manner. It would be better left unsaid.
2b simply means that the speaker didn't create the control mechanism. The else is required for this sentence or it's fatuous.

3a When someone wants to complete that task, they'll get it done
3b When someone else wants to complete that task, they'll get it done

3a includes the possibility that the speaker is a possible someone who might want to complete the task and who, therefore, will get it done.
3b excludes the possibility in 3a.
The else is required for this sentence if you want to make clear that you won't complete the task. If you want to be cryptic about it, the else is clearly contraindicated.

Q: Where's your iPAD? I want to borrow it.
A1: I gave it to someone. [else would be wrong here]
Q: To your girlfriend?
A2: No, I gave it to someone else. [else is required here]

Answer 4

It's remarkable to me how much the meaning of the sentence does change when you remove the else. In every example, the else emphasizes that you're not talking about the original or implied subject or object.

The following bracketed phrases are how I infer the unspoken meaning behind else in the example sentences.

The man wants to be like someone else. [He doesn't want to be like himself/a topical person.]

Someone else created that control mechanism. [It wasn't created by the person we originally thought.]

When someone else wants to complete that task, they'll get it done. [I, however, do not want to complete that task (so it won't get done right now).]

For contrast:

The man wants to be like someone. [We're being coy and don't want to say who it is he wants to be like.]

Someone created that control mechanism. [It wasn't created by the arbitrary interaction of particles. There must've been some Intelligent Design. Proof at last! >;) ]

When someone wants to complete that task, they'll get it done. [It's not a priority, and I might get around to it if someone else doesn't.]