Does Islamic law govern reality, or does reality govern Islamic law?

The Sharia is the ultimate arbiter, and reality must be dealt with through knowledge of the rulings of Islamic law, because this is an established principle that brooks no hesitation. Believers must obey Allah and His Messenger and refer to them for judgment. The Sharia takes into account the reality of those upon whom duties are enjoined through rules such as: capacity is a prerequisite for legal responsibility, harm is to be removed, hardship brings ease, custom is authoritative, and matters are judged by their intentions. The legal ruling is fixed and does not change if the circumstances of the cases are the same and their underlying reasons are unified. However, fatwas and rulings may change when applied to specific cases due to a change in the underlying reason or the emergence of relevant incidental factors, such as rulings based on custom and tradition which change with the change of custom across time and place.