Can we create a system without the law of modus ponens?
- John-Michael Kuczynski
- Jan 22, 2021
- 1 min read

Not possible.
Modus ponens is basically to the effect that you can infer it if it follows.
Without it, you are in dry dock, inference-wise.
Of course, you can always tinker with the way it is expressed. Instead of saying
((P->Q) &P)->Q,
you can say:
-((-P or Q)&Q)&-Q)
But given that ‘P->Q’ is definitionally equivalent with ‘-P or Q’, this isn’t exactly a way to get rid of modus ponens. Same holds if you try any other work-around.





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