Hi Jonathan,
It is very nice to re-meet you here. You wrote a fantastic Essay, congrats. Here are my comments:
1) Playing is the main reason for which I work like a researcher. In general, it is very s difficult for scientist becoming rich people, but they have the good luck to play in all their life!
2) I think that it is important to teach youngest children, starting from childhood, that science is playing. That is the best way to initiate them to science. I were lucky from this point of you as I had a teacher in my elementary school who initiated me to science in that way.
3) I did not know the nice Einstein's aphorism that "Play is the highest form of research", thanks for introducing me to it.
4) I completely agree with your statements that "We need to communicate that is isn't all hard work or memorization, that Science is and should be fun". In fact, I consider popularizing science as a kind of mission.
5) Your statements that "But once the developmental landmark is reached, allowing them to accurately estimate the dimensions of things around them, children also acquire an increasing ability to recognize and employ symbols, and to develop symbolic reasoning" is exactly what I am seeing with my son David, 3 years old!
6) I completely agree with the conclusions by Joseph Chilton Pearce and Michael Mendizza that emphasize the value of play for learning at all ages.
7) Although the notion that knowledge has value for its own sake is unpopular these days, it is my life philosophy.
8) I agree with my friend Doug Osheroff that researchers should question the wisdom of today's theorists. Sadly, this important point is made difficult by "political" and economic reasons.
As your departed friend Ray Munroe would say I had fun in reading your Essay. Thus, I am going to give you an high score. Congrats again and best luck in the contest!
Cheers, Ch.