Decent memory is a matter of livelihood, of independence, most of all of identity.

Human memory is the ghost in the neural machine, a widely distributed, continually changing, multidimensional conversation among cells that can reproduce both the capital of Kentucky and the emotional catacombs of that first romance.

The news last week that scientists had developed a brain implant that boosts memory — an implantable “cognitive prosthetic,” in the jargon — should be astounding even to the cynical.

App developers probably are already plotting yet another brain-exercise product based on the latest science. Screenwriters working on their next amnesia-assassin scripts got some real-life backup for the pitch meeting.

The scientists are in discussions to commercialize the technology, and so people in the throes of serious memory loss, and their families, likely feel a sense of hope, thin though it may be. These things take time, and there are still many unknowns.