P => Q
says nothing about what happens if ~P.
Hello,
Struggling to get my head around this.
So we have this statement.
-----------------------------------
If it rains on Monday then mark will carry an umbrella on Monday.
It does not rain on Monday.
You deduce:
Mark does not carry an umbrella on Monday.
-------------------------
So if we assume that P means it does not rain on Monday.
and Q means Mark doesn't carry an umbrella on Monday.
So we know P>Q and Q is true then its valid? but this doesnt seem right as P is the opposite of the opening suggestion in the statement.
Any help?
2 answers
deduction is incorrect
draw Venn diagram
we only know that the rainstorm is in the umbrella circle. He could easily carry the umbrella in a dry northwest breeze.
hypothesis:
If a cow, then a mammal
Converse:
If a mammal, then a cow
(false)
Inverse:
If not a cow, then not a mammal (false)
Contrapositive:
If not a mammal, then not a cow (true)
draw Venn diagram
we only know that the rainstorm is in the umbrella circle. He could easily carry the umbrella in a dry northwest breeze.
hypothesis:
If a cow, then a mammal
Converse:
If a mammal, then a cow
(false)
Inverse:
If not a cow, then not a mammal (false)
Contrapositive:
If not a mammal, then not a cow (true)