Thought experiments

• The experience machine

  A machine offers any felt life you choose, while you are not actually living it.

• The runaway tram

  A tram will kill five people unless it is diverted onto a track where it will kill one.

• The transplant

  Five patients can be saved only by taking the organs of one healthy person who did not consent.

• Predicting a choice

  A predictor that has never been wrong names your choice before you make it.

• The perfect copy

  Your body is destroyed and a perfect physical and psychological duplicate is made elsewhere.

• A universe without a purpose

  The universe has no purpose of its own. The question is what follows for the meaning of a life.

• A machine that reports pain

  A machine organized as a nervous system says that it is in pain.

• Observation and necessity

  Logic says the thing you seem to see is impossible. The seeing still looks careful.