===Relational quantum theory====

<blockquote>An interpretation of [[quantum theory]] according to which the quantum state of a particle, or of any subsystem of the universe, is defined, not absolutely, but only in a context created by the presence of an observer, and a division of the universe into a part containing the observer and a part containing that part of the universe from which the observer can receive information. Relational quantum cosmology is an approach to quantum cosmology which asserts that there is not one quantum state of the universe, but as many states as there are such contexts.<cite>Lee Smolin</cite></blockquote>

More on information and observers see: [[Bekenstein Bound]].