Modern science (and scientists such as Stephen LaBerge) argues that the dream world is a simulation of the real world. In a bid to achieve authenticity, many of the features of the real world are faithfully replicated. However, our mind is not perfect: there are a few key aspects which it fails to reproduce.

Having this in mind, one can use these innacuracies in order to test reality and to discern if they are in a dream or not.

The table below states some common inconsistencies between the real world and the dream world.

The real world The dream world
Actions have short-term and long-term consequences. Actions do not carry long-term consequences.
Free will is given to everyone whenever possible (on a non-philosophical level at least). The dreamer is often led 'on-rails' through a situation until he or she becomes lucid or wakes up.
Surreal events seldom occur, and when they do, they are met with suspicion and suprise. Frequent surreal events often go unnoticed.
Machines often function as intended (though not always!) Machines malfunction easily and frequently.
The world, and all the objects in it, are governed by fundamental forces, and these cannot be ignored. The dream world is far from logical. Gravity and other forces can be overcome or altered with ease.
A change of scene requires a car, a plane ticket, or hiking boots. Scene changes can occur spontaneously.

Some other more in-depth differences exist. For instance, a dreamer's own reflection in the mirror is usually misshaped and dark in dreams, while it is neat and flawless in reality.

See also[]

Reality check

Lucid dream

Dream Initiated Lucid Dream