Former Vice President Joe Biden started out the third Democratic debate on ABC pretty strong. But as the night went on, Biden’s answers started to make less and less sense. He couldn’t answer a point-blank question about Obama’s deportation record and responded to question about US withdrawal from Iraq with a frankly incomprehensible assertion about the country’s ethno-religious divisions.

But by far his strangest answer of the night came near the end, when he was asked a question about his controversial record on race and schools. Specifically, he was confronted with comments from 1975 on slavery, in which he said “I’d be damned if I feel responsible to pay for something that happened 300 years ago.”

So Biden was asked whether he still held these attitudes: “What responsibility do you think that Americans need to take to repair the legacy of slavery in our country?” What follows is a transcript of his rambling answer (I have omitted nothing), which for some reason includes references to record players and Venezuela:

Well, they have to deal with the — look, there’s institutional segregation in this country. From the time I got involved, I started dealing with that. Redlining banks, making sure we are in a position where — look, you talk about education. I propose is we take the very poor schools, triple the amount of money we spend from $15 to $45 billion a year. Give every single teacher a raise to the $60,000 level. Number two, make sure that we bring in to help the teachers deal with the problems that come from home. The problems that come from home, we have one school psychologist for every 1,500 kids in America today. It’s crazy. The teachers are — I’m married to a teacher, my deceased wife is a teacher. They have every problem coming to them. Make sure that every single child does, in fact, have 3, 4 and 5-year-olds go to school. Not day care, school. Social workers help parents deal with how to raise their children. It’s not that they don’t want to help, they don’t know what to play the radio, make sure the television — excuse me, make sure you have the record player on at night, the — make sure that kids hear words, a kid coming from a very poor school — a very poor background will hear 4 million words fewer spoken by the time we get there. MODERATOR: Thank you, Mr. Vice President. Biden: No, I’m going to go like the rest of them do, twice over. Because here’s the deal. The deal is that we’ve got this a little backwards. By the way, in Venezuela, we should be allowing people to come here from Venezuela. I know Maduro. I’ve confronted Maduro. You talk about the need to do something in Latin America. I’m the guy that came up with $740 million, to see to it those three countries, in fact, changed their system to people don’t have to chance to leave. You’re acting like we just discovered this yesterday. Thank you very much.

It’s hard to tell, but I think the reference to the “record player” is a reference to dubious research suggesting poor kids hear fewer words at home than wealthy kids. I think; again, it’s hard to tell.

The bigger takeaway, though, is twofold.

First, the Democratic frontrunner’s answer to a question about his alarming past comments on race — arguably the central issue of the Trump era — is a grab bag of policies plus some word salad involving record players and Venezuela. He simply does not attempt to reconcile his comments with his current attitude; we’re still in the dark as to what he actually thinks about his old attitudes on slavery. It’s an especially notable dodge given that Biden launched his campaign in Charlottesville, positioning himself as the opposite number to Trump’s racial demagoguery.

Second, the nonsense parts of the answer (the record player reference in particular really made me think about some of Trump’s rambles) has to raise questions about Biden’s mental fitness for office, especially given his age. It’s an uncomfortable and difficult topic to talk about. But it’s an issue that, as my colleagues Tara Golshan and Ella Nilsen explain, Democratic voters are increasingly worried about.