Horse sense is a good judgment which keeps horses from betting on people.

The joke hinges on reversing expectations: “horse sense” is supposed to describe a human virtue, but Fields imagines it as a literal quality possessed by horses. In his punchline, good judgment is defined as the wisdom to avoid betting on people—implying that humans are less reliable, more irrational, or more morally compromised than animals. The humor is both cynical and self-deprecating: it mocks gamblers’ faith in human character while also poking at humanity’s tendency to romanticize its own “common sense.” Like many Fields aphorisms, it compresses a bleak view of human nature into a neat, memorable paradox.