It was during the contentious years of the Vietnam War that Matthew Lipman, a philosopher and educator, found that many Americans were having trouble presenting their views about the conflict cogently, and it distressed him.

Lipman, who was teaching at Columbia University at the time, concluded that many adults could simply not reason well for themselves, and he feared that it was too late for them to learn. So he responded with a radical idea: to teach children philosophy beginning in pre-kindergarten and continuing through high school.

Lipman died Dec. 26 in West Orange, N.J.

He was 87.

Lipman’s initial focus was on teaching logic, but the curriculum soon embraced concepts like truth, justice and freedom.

Gareth B. Matthews, an emeritus professor of philosophy at the University of Massachusetts, Amherst, said in an interview on Wednesday that Lipman was “the most influential figure” in helping youngsters develop philosophical thinking.