I wholeheartedly agree based on my own kids, but want to add a caution lest someone misunderstand: this testing, learning, and growing is of a kind that can
only be done without adult supervision. It's not something that you can give them with a private lesson. It's not something that can be taught in a classroom. It's not something that can happen
at all without adults letting the kids figure it out on their own by random trial and error.
Parents generally have a strong instinct to try to make things easier for their kids than they were for themselves growing up. We know the food is hot, so we blow on the kid's food or let it cool before giving it to them. We know the toy will break if it's repeatedly thrown down the stairs, so we impose a rule that "we don't do that in our house". We know X, Y, or Z, so we sit down with them and explain it to them.
I don't think that these explanations and rules have no place (I don't want a child learning what heat is by falling onto a wood-burning stove!), but we need to recognize that it's a strictly inferior way of learning something when compared to experience. And as you point out, unstructured play is where kids get that experience in a low-stakes environment.
Play serves a valuable purpose, but as soon as parents get involved to try to assist the purpose evaporates.
Parents generally have a strong instinct to try to make things easier for their kids than they were for themselves growing up. We know the food is hot, so we blow on the kid's food or let it cool before giving it to them. We know the toy will break if it's repeatedly thrown down the stairs, so we impose a rule that "we don't do that in our house". We know X, Y, or Z, so we sit down with them and explain it to them.
I don't think that these explanations and rules have no place (I don't want a child learning what heat is by falling onto a wood-burning stove!), but we need to recognize that it's a strictly inferior way of learning something when compared to experience. And as you point out, unstructured play is where kids get that experience in a low-stakes environment.
Play serves a valuable purpose, but as soon as parents get involved to try to assist the purpose evaporates.