Rule of Assumption

Context
The rule of assumption is one of the axioms of natural deduction.

The rule
An assumption may be introduced at any stage of an argument.
 * Abbreviation: $\textrm {A}$
 * Deduced from: Itself
 * Depends on: Nothing

Explanation
There is no question of making sure that the assumption is true - all we are concerned about is making sure that any conclusion based on the assumptions made are valid.

The introduction of an assumption $p$ into an argument by means of the Rule of Assumption can be interpreted in natural language as: "What if $p$ were true?"