The blog series RJB is based on my reading of the Jefferson Bible for the 21st Century, published by Humanist Press. By extension, it is a secular re-reading and reinterpretation of the Gospels.
Beware of false prophets, who come to you in sheep’s clothing, but inwardly they are ravenous wolves. You will know them by their fruits. Do men gather grapes from thornbushes or figs from thistles? Even so, every good tree bears good fruit, but a bad tree bears bad fruit. A good tree cannot bear bad fruit, nor can a bad tree bear good fruit. Every tree that does not bear good fruit is cut down and thrown into the fire. Therefore by their fruits you will know them. – Matthew 7:15-20
The above Gospel passage contains one of the most enduring, common-sense pieces of advise ever given. It is a warning against false Gurus, but might also apply to politicians, good or bad friends, good or bad workers/employers, and so on.
It is true that the best and most legitimate way to judge a person, a religion, a philosophy, etc. is by its fruits. If we see violence being constantly produced by a certain political philosophy or religious worldview, then it is entirely appropriate to say that it produces violence, because that is what our senses and faculties are reporting to us. If we see them producing joy, or anger, or unhappiness, or discontent, then we can say those things. If a person is constantly frustrated, or disloyal, or always arguing with others, we should take heed before we engage them in association and experience their disloyalty and belligerence directly. This is just a matter of common sense.
Bearing fruits is also a metaphor for what we do with our existential condition. “By their fruits you will know them” is an eternally applicable existential truth related to self-creation, to how we define ourselves in relation to our society and our natural context, and it related to the existential and Sartrean adage “existence precedes essence”. That is, we are what we do with what life gives us: as free people, we have no choice but to engage in a process of self-definition. We first exist, and then within our context we are free to determine how we identify by our works and habits.
Each one must have a great work in order to be magnanimous, great existential projects that create meaning and, perhaps, make a better society. And by our fruits we define ourselves.