NOT SENT Dear Alex, The summer ended on a very warm day. The high in Belmont was 86. The forecast for tomorrow is for similarly high temperatures. My memory corroborates the studies that show the earth to be getting warmer, but I can subscribe to no dogmatic assertion for the cause. The standard by which I calibrate my ignorance is ophthalmology, where in some instances the origin and the course of the pathologic process are certain beyond doubt, while in other instances the disease remains inscrutable, both its past and its future indefinable. I cannot escape the social and political consequences of uncertainty. For centuries, from the beginnings of our history, where experience fails we physicians have found certainty in language (nowadays in statistics). The world demands certainty and insists on action. The contemplation of something that is not, and perhaps cannot be understood is intolerable; and even more so, the absence of remedy. That nothing effective can be done is unbearable. Hence logic is jettisoned with a demand for action that culminates in social coercion. Does anyone know how climate change can be arrested or reversed? When confronted with danger, we human animals seek refuge in the herd. The demands of children and adolescents for action to "prevent" climate change, remind me of descriptions of medieval children's crusades in 1212, where thousands of children are said to have crossed the Alps into Italy with the expectation that God would sunder the Mediterranean for them so that they could pilgrimage to the Holy Land on dry land, as He had previously opened the Red Sea for the Israelites when they excaped from Egypt. And they were devastated when this did not happen.