What simply states what will be observed and always true but does not explain why

A Law

Explanation:

A scientific law talks about a law which has been observed and found to be always true but does not explain the reason behind it or the underlying causes which makes such an event to occur.

For example the law of conservation of energy states that energy can neither be created or destroyed, but can be converted from one form to another or transferred from one object to another.

In this law there is no reason why this happens and doesn’t state the causative factors.