Axiom:Rule of Assumption
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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?"
Sources
- E.J. Lemmon: Beginning Logic (1965): $\S 1.2$
