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- ola:: Negating the original consequent as the antecedent, does not negate the original antecedent as the consequent
- @:
INPUT[aliases][] - Taking a true conditional relationship, under certain insufficient assumptions, and invalidly inferring its converse
- there may be uncaught alternative antecedents
- one of the four Mixed Hypothetical Syllogisms
- the opposite statement, denying the consequent, is valid
- eg: lamp in dark
- PREMISE:
ifthe lamp is broken →thenthe room is dark - CONDITION: no other lights in room, nighttime, closed windows (insufficient)
- CONVERSE:
ifthe room is dark →thenthe lamp is broken - analysis:
- there are other possible antecedents, uncaught by the condition
- if lamp is working, but is off
- if there is no lamp in the room
- there are other possible antecedents, uncaught by the condition
- PREMISE:
- confusion of Necessity and Sufficiency
- the forward is valid, therefore necessary
- but the backward is insufficient, therefore invalid
- it is necessary antecedent that “a lamp is broken” (non-working) for the consequent of a dark room
- but “a dark room” is an insufficient antecedent for the consequent “a broken lamp”
- the forward is valid, therefore necessary
- eg: obviously false conclusion
- syllogism
- If someone lives in KL, then they live in Malaysia
- Joe lives in Malaysia
- Therefore, Joe lives in KL
- other antecedents exist: there are other states in Malaysia besides KL
- necessary-sufficiency
- “living in KL” is necessarily also “living in Malaysia”
- but “living in Malaysia” is insufficient to be “living in KL”
- denying the consequent is valid:
- ¬Q: Ken doesn’t live in Malaysia
- ¬P: Ken doesn’t live in KL
- contrapositive of the first statement
- syllogism
- eg: other antecedents
- note: wait this isn’t converse error, this is just generalisation?
- syllogism
- If animal is a dog, it has four legs
- cats has four legs
- Therefore, cat is dog
- related to Necessity and Sufficiency
- “four-legged” is necessary to describe “dog animal”
- but “four-legged” is insufficient to conclude “dog animal”
- other antecedents exist
- other antecedents like: If animal is a (cow, deer, etc.)
- can still lead to the same consequent: then it has four legs