- "Right now, I can't say I know what they want from me. But I'm willing to take a leap of faith, and believe that they're guiding me. I'm asking you to take that leap with me."
- - Benjamin Sisko (DS9: "The Reckoning")
Leap of faith was a term used to describe one's decision to have faith or believe in something that was empirically unknowable at the time, then act on said belief by making a choice that seemed irrational otherwise.
Starfleet officers were trained to act scientifically and rationally based on learned knowledge and facts of the situation. Starfleet admirals generally disliked religious inclinations as an excuse to act. (DS9: "Rapture")
Data took a leap of faith in order to believe that he could become Human, becoming something other than he was. (TNG: "Rightful Heir") Benjamin Sisko entrusted the Bajoran Prophets to save his son, even as they were trying to kill the Pah-wraith that was inhabiting Jake's body. (DS9: "The Reckoning") Janeway ignored her first officer and chief medical officer advice to wait for a scientific way to save Kes, and she took a leap of faith that not only would Kes be saved, but that she herself would not die. (VOY: "Sacred Ground") In the anti-time past, Jean-Luc Picard asked his crew to take a leap of faith and trust him, when he ordered the USS Enterprise-D into a temporal anomaly discovered in the Devron system. (TNG: "All Good Things...")