Difficulty in distinguishing whether a singular or plural verb agrees with a subject; one which includes "both" followed by a prepositional phrase

Question

I have written the following sentence:

While I think the Austrian School's fixation both on natural prices and the rate of interest were akin to jousting at windmills...

First, am I correct in assuming that "fixation both on natural prices and the rate of interest" composes the entire subject?

Second, does "both" modify this sentence in any legitimate way, or is its inclusion merely tautological? Does its inclusion represent a conjunction reduction wherein the sentence effectively reads as "fixation on natural prices and fixation on the rate of interest were akin to jousting at windmills"? Does the inclusion of "both" make this a compound subject? If not...

Finally, and most importantly, is "were" the appropriate verb in this case; or, rather, should I have used "was"? As "fixation" is singular, and prepositional phrases aren't supposed to affect the verb, my gut is indicating the latter would be the correct verb to use in this case.

Answer 1

Your subject is the Austrian School's fixation both on natural prices and the rate of interest and its head is fixation. Therefore, since it is a singular noun, you definitely need a singular verb (was). Your rightly name both on natural prices and the rate of interest a prepositional phrase that does not affect the verb.

I am not sure what you mean by modify this sentence in any legitimate way. Both... and may not add new information to a sentence, but it certainly emphasises the presence of the two elements. Macmillan says that this phrase is

used for emphasizing that each of two things is true

• a plant that grows in both Chile and Argentina.

You can understand it as meaning not only... but also....

No, this is not a compound subject. Your sentence does not speak of two fixations, but of one. The fact that the fixation concerns two elements, does not make it plural.

If you had

While I think both the Austrian School's fixation on natural prices and its fixation on the rate of interest were akin to jousting at windmills...

then yes, it would be a compound sentence, but a rather chunky one...