In the waning hours of a marathon second day of Kentanji Brown Jackson’s confirmation hearings, Senator Marsha Blackburn (R-TN) asked whether Jackson could define the word “woman.” Jackson said she could not, at least, “not in this context.” After all, she said, she is “not a biologist.”

It is easy to mock her response. But it was not, from a progressive perspective, an easy question to answer. It forces the respondent to navigate several competing and contradictory left-wing claims about sex and identity.

The first is that the United States is, in some enduring sense, “a patriarchy”—that is, it was designed by men to benefit men and subjugate women. This claim requires a definition of the word “woman” so clear and unambiguous that a group of men could successfully construct an entire social order dedicated to the oppression of women.

The second claim, related to the first, is that women are and have been corporately oppressed in the United States. This again requires that “women” exist as a distinct and definable class of persons.

The third claim is that marginalized groups of people have perspectives that are unique to those groups and inaccessible to people who do not belong to those groups. Hence proponents’ claim that it is important to have a “black woman’s perspective” on the Supreme Court, which implies that women have a perspective meaningfully different from and inaccessible to men.

The fourth claim, quite at odds with the first three, is that a person with male reproductive organs and a Y chromosome who claims to be a woman is, in fact, a woman. Womanhood, according to this view, has no objective component, and can be claimed by any person who sincerely identifies as “a woman.” It is a self-referential definition.

If Jackson answered Blackburn’s question correctly—”a woman is an adult human female”—she would have run afoul of the fourth claim. If she answered incorrectly, she would run afoul of the first three claims. She also would have seemed like a lunatic.

In Wednesday’s hearings, Senator Ted Cruz (R-TX) tried to force Jackson to once again navigate this thicket of contradictions. Cruz asked Jackson whether a man who identified as a woman would have Article III standing in a class-action sex-discrimination lawsuit. It was a good question. It used a live legal issue to get at the heart of Blackburn’s question. Jackson refused to answer, saying she would, if presented with such a case in the future, follow the same judicial methodology that she previously described to the committee.

It is understandable that Jackson, as a prospective Supreme Court justice, would not want to speculate on a hypothetical case. It is nevertheless disappointing that a person nominated to the Supreme Court in part on the basis of her sex would be unable to define what a woman is.