'Money is an essential part of self-esteem.' : How is this the missing premise?

Question

_{Source: A Concise Introduction to Logic (10 Ed, 2008) by Patrick Hurley}

[Question on p 597:] 6. Missing Premise Question

Unequal pay for men and women is a completely indefensible practice and one that must be stopped immediately.
[1.] After all, can anyone seriously doubt that women have as much right to self-esteem as men?
[2.] Surely this fact alone is reason enough to justify their right to earn as much money as men.

Which of the following is an assumption on which the above argument depends?

(A) A person who has less money than another has less self-esteem.
(b) People who do not have jobs lack self-esteem.
(c) Women and men who perform similar jobs should earn similar salaries.
(D) Equal pay for equal work is a constitutionally guaranteed right of all workers.
(E) High self-esteem is as important to women as it is to men.

[ANSWER on p 603:] 6. This argument has the following structure:

[1.1.] Stated: Women have as much right to self-esteem as men.
[4.] Missing: Money is an essential part of self-esteem.
[3.1.] Stated: Women have as much right to money as men.
Answer: (A)

My Problem: I agree with the solution’s paraphrases (1.1 and 3.1), but I disagree with 4.
To me, the missing premise should instead be 5 as follows:

5. Since women have as much right to self-esteem as men, women should earn as money as men.

6. So is 4 wrong?

7. Rather than ‘essential part’, should 4 be stated as a Necessary Condition or Sufficient Condition?

Answer 1

This is a textbook problem set, so it's reasonable to expect a few possibilities that all work out. In a real debate, someone might take the time to clarify this.

In this case, I think you could fill in the missing premise with your premise 5: "Since women have as much right to self-esteem as men, women should earn as money as men." and you would create a more complete argument. However, since the book isn't actually asking for the missing premise (they're just using it to help explain what's going on), they chose a simpler premise.

Your [5] is technically a valid choice of a missing premise, but it would be a hard to defend one without taking a step back and arguing for missing premise [4]. The authors just skipped past the step you took, and went straight for what is traditionally taught as a bad life lesson. We generally try to teach our children money is not essential to self-esteem, so they felt they could get away with claiming that was the missing premise... it was simply more of a slam dunk.

Edit: To answer your question, the textbook is not asking for "the missing premise" in that they're not asking you to develop the most perfect argument possible, then identify which premise isn't there. They're just looking for an assumption. It doesn't have to be the most complete, it just has to be something there.

As for how [4] implies [5], it doesn't. It's the other way around. Your [5] implies [4] is a needed part of the argument. If you use your [5], "Since women have as much right to self-esteem as men, women should earn as money as men," there would still be a missing premise, because there's no obvious connection between a woman's rights to self-esteem and money. That connection can only be made by also including [4], "Money is an essential part of self-esteem." Only through [4] can you defend [5]