Is this ellipsis grammatical?

Question

Which of these sentence constructions is correct? The only difference is the last word.

1. Sometimes questioning others' assumptions is not the hardest part of being an activist; the hardest part is questioning our own.
2. Sometimes questioning others' assumptions is not the hardest part of being an activist; the hardest part is questioning our own assumptions.

Answer 1

These two sentences are both correct in a sense that they are grammatical. In the first sentence, the word own is used as a pronoun, while in the second sentence it plays the role of an adjective.

own

[pronoun] that which belongs to oneself ⇒ the car is his own; I have reasons of my own

[adjective] belonging, relating, or peculiar to oneself or itself (used to strengthen a preceding possessive) ⇒ his own book, her own idea

The first sentence would be a better choice of expression. It is always good to omit words that are unnecessary.

Answer 2

There is no fault to be found in either. The first seems more elegant.