The physics of connection

IF I HELD A HAMMER CORRECTLY, the way my father taught me, and then swung it down on a rock, the rock would break. I would have caused that to happen. I would have transferred kinetic energy from my arm to the hammer’s handle and then to the hammer’s head and then to the rock. The energy would cleave bonds in the rock, and release sound and heat. My father taught me all that, long ago.

Now he lives in an adult foster home outside Corvallis, Oregon. When I grin at him as he sits in his wheelchair, he grins back. I can cause that to happen, too. But how? There is no law of physics to explain the transfer of emotions, no equation to describe the difference between what I send and what my father receives. I need that equation because that difference, I fear, is increasing.

When I was young,