Imagine being approached by some scientists to participate in a quick, non invasive experiment that will be financially rewarding (given that you correctly answer their questions).

You agree and so are placed in a large, but poorly lit room that is filled with different items. The objective is then explained: To find your way to the other door (on the other side of the room). They also explain that should you choose to only walk straight, you will not encounter any obstacles-better still, the straight path has some luminous footprints on the floor that can be easily followed to ensure that you don't jeer off course.

You decide to take the path you can see and eventually get to the end and exit the room. You are then asked to fill in a quick survey on your experience, so you can claim your reward. As you glance at the questions, you realise that they all relate to the items which you couldn't see but were apparently present.

The scientists thank you for participating but remind you about the conditions that would enable you win the cash prize... unfortunately, you have not qualified. Is that fair?