Son (looking at the ground from a park bench): Dad, how do I know that's a brick?
Dad: Don't be silly, you know bricks when you see them.
Silence -- dad thinks about his interrupted business while waiting for the child's delayed medical appointment.
Branden: But every brick has different cracks, what makes a brick a brick?
Dad: All these bricks have different details we just know they're bricks because they look like bricks.
Long silence.
Branden: How do we know which car is ours?
Dad (impatient but starting to pay attention): I know you know the answer. What are you really asking?
Branden: If we changed the bumpers, then changed the doors, and then changed each of the other parts, it would still be our car. What makes it our car?
Dad (now sincerely curious): Why are you asking these questions?
Branden: My teacher told us that when we get older all the cells in our body die and are replaced by new ones. But my friend, Ali, will always be my friend Ali when all his cells are changed. What makes him Ali?
Dad: Wow, that's a really good question. And I don't know the answer. I need to think about it but I promise I will give you my best answer when I have one. [Note: a fact-check revealed that brain cells are not entirely replaced with age but that is beside the point of the conversation -- Ali is not just a brain, and our car is not just an assembly of its original parts]
Since having that conversation, I rarely dismissed kids' questions, however silly they seemed, and I learned that kids have much deeper thoughts than I had ever imagined. At the time of the conversation, my son was about 10 years old. I could easily have missed a great opportunity to get a deep appreciation for children's musings. A later blog post will explain the answer that finally satisfied me.