we are all prisoners of our thoughts. - Sam Harris

In a now famous thought experiment, the philosopher Derek Parfit asks us to imagine a teleportation device that can beam a person from Earth to Mars. Rather than travel for many months on a spaceship, you need only enter a small chamber close to home and push a green button, and all the information in your brain and body will be sent to a similar station on Mars, where you will be reassembled down to the last atom. Imagine that several of your friends have already traveled to Mars this way and seem none the worse for it. They describe the experience as being one of instantaneous relocation: You push the green button and find yourself standing on Mars — where your most recent memory is of pushing the green button on Earth and wondering if anything would happen. So you decide to travel to Mars yourself. However, in the process of arranging your trip, you learn a troubling fact about the mechanics of teleportation: It turns out that the technicians wait for a person’s replica to be built on Mars before obliterating his original body on Earth. This has the benefit of leaving nothing to chance; if something goes wrong in the replication process, no harm has been done. However, it raises the following concern: While your double is beginning his day on Mars with all your memories, goals, and prejudices intact, you will be standing in the teleportation chamber on Earth, just staring at the green button. Imagine a voice coming over the intercom to congratulate you for arriving safely at your destination; in a few moments, you are told, your Earth body will be smashed to atoms. How would this be any different from simply being killed? To

The year was 1987, but it might as well have been the Summer of Love: I was twenty, had hair down to my shoulders, and was dressed like an Indian rickshaw driver. For those charged with enforcing our nation’s drug laws, it would have been only prudent to subject my luggage to special scrutiny. Happily, I had nothing to hide. “Where are you coming from?” the officer asked, glancing skeptically at my backpack. “India, Nepal, Thailand…” I said. “Did you take any drugs while you were over there?” As it happens, I had. The temptation to lie was obvious — why speak to a customs officer about my recent drug use? But there was no real reason not to tell the truth, apart from the risk that it would lead to an even more thorough search of my luggage (and perhaps of my person) than had already commenced. “Yes,” I said. The officer stopped searching my bag and looked up. “Which drugs did you take? “I smoked pot a few times… And I tried opium in India.” “Opium?” “Yes.” “Opium or heroin? “It was opium.” “You don’t hear much about opium these days.” “I know. It was the first time I’d ever tried it.” “Are you carrying any drugs with you now?” “No.” The officer eyed me warily for a moment and then returned to searching my bag. Given the nature of our conversation, I reconciled myself to being there for a very long time. I was, therefore, as patient as a tree. Which was a good thing, because the officer was now examining my belongings as though any one item — a toothbrush, a book, a flashlight, a bit of nylon cord — might reveal the deepest secrets of the universe. “What is opium like?” he asked after a time. And I told him. In fact, over the next ten minutes, I told this lawman almost everything I knew about the use of mind-altering substances. Eventually he completed his search and closed my luggage. One thing was perfectly obvious at the end of our encounter: We both felt very good about it.

the fact that unjustified beliefs can have a consoling influence on the human mind is no argument in their favor.