A person is made up of three parts. The mind, the heart, and the body. The mind represents thinking which is unseen. The heart in the body represents the affections that are unseen. The body represents the appetites that are unseen.
A life mastered by the appetites ends in morbid obesity, addiction, incarceration, and loneliness. This is not a good life.
A life mastered by thinking seems right but — in the end — is foolish.
A good life is aligning thinking and appetites to serve the affections.