Examples of reality assumptions include time, free will and ethics. Another example of a reality assumption arose after the discovery that light traveled in waves. The assumption was that there must be an "ether" that the light waves travel through.
This assumption was hypothesized based on how water waves travel through water and how sound waves were disturbances in the air. However, Einstein's theory of special relativity proved that there was no such "light ether" and that the reality assumption was false.
Time is also a reality assumption because it cannot be observed. Time is a reality assumption that connects the past with the future. However, a person is anchored in the present moment and therefore is unable to perceive the dimension of time. The individual simply has to assume that it exists.
Free will and ethics are reality assumptions that account for things like control, responsibilities, consequences and morality. Ethics is a system that attempts to establish a list of behaviors that humans perceive as acceptable and unacceptable. This system gives an individual the ability to plan and make morally correct decisions at a future point. The individual assumes that any morally correct decision that he makes in the future will be considered acceptable by society at that future point.