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put this solution on YOUR website! 1. T ⊃ B Prove: L • B (Hint this involves using the Addition Rule)
2. T ⊃ ~X
3. T
4. X
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There is a logical contradiction in any attempted proof. Look at it.
1. T—>B Premise
2. T—>~X Premise
3. T Premise
4. X Premise
5. ~X 3,2 Modus Ponens (MP)
6. X & (~X) 5,4 Contradiction — we must stop here!
Since the attempted proof contains a contradiction, one can not make a sound proof of L & B. Note that another way to look at this: it may be possible to "prove" L & B but the proof will not be sound. This is similar to proving 2=1 when there is a division by zero somewhere in the chain of reasoning.
