the.com/modus tollens
Logic's hitman: deny the consequent, watch your whole argument collapse.
means A valid form of logical inference where, if a conditional 'if P then Q' is true and Q is false, you conclude that P must also be false.
from Latin, short for 'modus tollendo tollens' — 'the mode that, by denying, denies.' The verb 'tollere' means to lift, take away, or destroy; here it 'takes away' the conclusion to take away the premise. The term comes from medieval logicians who Latinized the inference rules of Aristotelian and Stoic logic, pairing it with its sibling modus ponens, 'the mode that affirms.'
- the form
- If P then Q; not Q; therefore not P
- falsification engine
- Popper built science's spine from this move
- latin name
- means mode that denies, in reverse
- sneaky failure
- humans botch it more than its cousin