28 lines
988 B
Markdown
28 lines
988 B
Markdown
---
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tags:
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- propositional-logic
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- logic
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---
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# Disjunction Elimination
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This rule is sometimes also referred to as _Constructive Dilemma_. This can be a
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bit tricky to understand because the goal is to derive or _introduce_ a new
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proposition separate from the disjunction you start out with. This may be
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disjunction, a single proposition or a proposition containing any other logical
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connective. You do this by constructing two sub-proofs, one for each of the
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disjuncts comprising the disjunction you start out with. If you can derive your
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target proposition as the conclusion of each subproof then you may invoke the
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conclusion in the main proof and take it to be derived.
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_Here is an example where Disjunction Elimination is used to derive a new
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disjunction._
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_Here are two further examples that use Disjunction Elimination to derive
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singular propositions_
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