GRADED A+.
Valid
1) If P, then Q
2) P
Therefore, Q
invalid
1) If P, then Q
2) Q
Therefore, P
valid arguments
an argument is valid iff when the premises are true, the conclusion must be true
or
an argument iff it's impossible for the premises to be true while the conclusion is false
sound arguments
iff 1) it's valid and 2) the premises are true
All sound arguments are ___
valid
some valid arguments are ___
unsound
all arguments must have a set of premises, but the set can be empty
true
all invalid arguments have false conclusions
false
all sound arguments are valid
true
a valid argument can have a false conclusion
true
the premises of a sound argument entail their conclusion
true