Erhard Seminars Training (EST) was a pseudo-religious organization founded by Werner Erhard in 1971, later morphing into Landmark Forum. With seminars that purported to help people better understand reality, both promote dangerous truth claims that often cause great distress in those attending.
Some like to say that there is no absolute truth. It's a fun mental exercise, but nobody - absolutely nobody - lives that way. How can I be sure? Try a little experiment...