Probability

Trying to find the actual Jesus is like trying, in atomic physics, to locate a submicroscopic particle and determine its charge. The particle cannot be seen directly, but on a photographic plate we see the lines left by the trajectories of larger particles it put in motion. By tracing these trajectories back to their common origin, and by calculating the force necessary to make these trajectories move as they did, we can locate and describe the invisible cause. Admittedly, history is more complex than physics; the lines connecting the original figure to the developed legends cannot be traced with mathematical accuracy; the intervention of unknown factors has to be allowed for. Consequently, results can never claim more than probability; but "probability," as Bishop Butler said, "is the very guide of life."

Morton Smith, Jesus the Magician (San Francisco: Harper & Row, 1982)