There are very few things in life about which we can really be "certain".
I think part of the problem goes back to government schools which no longer teach children how to think. They teach what to think. In all cases the teacher knows the precise answer -- and you better know it too. This works fine for math -- 2+2=4 (although this can be racist). Children are taught to parrot the "correct" answer. Don't question climate change, don't question evolution, don't question whether men can give birth. The answer is always very clear and your teacher will drill it into your head.
But in most other subjects, certainty is not guaranteed. You have to think about multiple viewpoints and diverse possibilities. What was the cause of WWI? What was the cause of WWII? In Asia? In Europe? What year did WWII start? 1937? 1939? 1941? Anyone who thinks that they "know" the right answer is deluding themselves. These are complex questions and it depends on viewpoint. If schools taught children to think in a flexible way, I think a fair number of psychological and interpersonal issues might be resolved more easily.
I think part of the problem goes back to government schools which no longer teach children how to think.
The article mentions this ... as ‘introspect’.
Something definitely lacking in our schools/parenting, these days.