TeachingLearning depends for its effectiveness on TeachingReaching. Time both helps and hinders my teaching. On the one hand, as I have become an old man, I know more, have more experience, more ideas, strategies, in short, a larger repetoire of resources on which I can draw. On the other hand, over time, there is more and more of a generation gap between me and you, and so it gets harder and harder for me to close this gap. (The gap has also widened as I have checked out of TV and news media pretty much altogether; come to think of it, perhaps it has narrowed.) To try to close the perhaps ever widening gap, I'll have to stretch to reach you. Conversely, you'll have to stretch to reach me. Collaborative TeachingLearning is already happening at the moment we begin to reach out to each other.
Update December 12, 2016: Now that I have gone blind in one eye, am going deaf, and have had several major surgeries, it has gotten harder for me to reach out. I am reminded of the opening scene from Vertigo. Please. Don't let me be that cop. Give me your hand! Give me your hand!