Republican presidential candidate Dr. Ben Carson continued to defend his recollection of his past on NBC's "Meet the Press" amid mounting questions about biographical discrepancies.

Carson brushed off criticism over a piece in the Wall Street Journal which said that after dozens of interviews with classmates, nobody remembered his role in sheltering students during race riots at his high school.

“Why would they know about that, unless they were one of those students,” Carson told NBC’s Chris Jansing.

Related: Carson Plays Defense as Biographical Questions Pile Up

However, the leading GOP candidate did admit that his timeline about meeting General William Westmoreland on Memorial Day in 1969 and subsequently being offered a scholarship to West Point could be wrong.

“Well I know he [Westmoreland] was there in Detroit…You know it may not have been Memorial Day. But it was sometime during the time that I was the City Executive Officer."

Another Carson anecdote — featured in his 1990 autobiography, "Gifted Hands" — recounts an issue with an exam while he was at Yale.

That story too has been called into question, prompting some to ask why neither Carson nor his campaign hasn't produced someone from his past to corroborate his version of events.

Some have suggested that his brother, Curtis Carson, would be a logical suggestion to confirm, at least, Carson's childhood anger.

However, Carson said, “My brother's not interested in talking to the media. And a number of other people aren't either, that I've talked to.”

When asked about whether he was ready for the intense scrutiny and vetting of a presidential campaign, Carson said he was but pushed back on whether what he is experiencing is fair.

“I have always said that I expect to be vetted, but being vetted and what is going on with me — ‘You said this 30 years ago, you said this 20 years ago, this didn’t exist’ — you know, I have not seen that with anyone else. If you can show me where that’s happened with someone else I will take that statement back,” he said.

Carson said this kind of scrutiny is born out of the “secular progressive movement in this country.”

He said he is a threat to that because he and his campaign are attracting “a great diversity of people and it worries them.”

While the chattering class may see these questions as a problem for the campaign, Carson credits them for contributing to a major fundraising haul this week. Yesterday, the campaign said he’s raised $3.5 million in the past week. In a tweet, Carson attributed this cash infusion to “media bias.”