My father in his last years was tentatively diagnosed as having Alzheimer’s. I never believed it. Now, new research on the human genome and, among other things, how canaries learn new songs brings us a little closer to understanding how memory works, and why it doesn’t.

Anyone who has seriously attempted it knows the impossibility of representing past events authentically, as they were lived and felt by the people involved. …. People then just didn’t think the way we do.