My grandmother taught a Sunday school class for senior adults up until the year before she died. She had tried to retire from it, but the class begged her to come back for one more year. She agreed, under one condition: “That if I lose my mind,” her blunt way of describing dementia, “you will immediately replace me without discussion. After all,” she reasoned, “how would I know?”

If meaning is inherently subjective, how would we know? How does anything mean anything? How is communication possible? How would my grandmother’s declaration make any sense at all?

The proposition that meaning is inherently subjective, if it does not eliminate meaning entirely, makes it impossible to distinguish between thought and dementia.