Question

Determine whether the following argument is valid or invalid.

Argument:
If a number is divisible by 2, then it is even.
The number 4 is even.
Therefore, the number 4 is divisible by 2.


The argument is valid by the Law of Syllogism.

The argument is valid by the Law of Detachment.

The argument is not valid.

The argument is valid but does not follow the Law of Syllogism nor the Law of Detachment.

Answer 1

Law of Syllogism states
If p implies q
And q implies r
the p implies r

p = a number is divisible by 2
q = it is even
r = The number 4 is even

So you decide if it is correct

Answer 2

this argument is invalid , i just realized

Answer 3

the law of detachment has the form

premise 1. if p then q .
premise 2. p
-----------
conclusion: q

Answer 4

@perl?

Answer 5

@kb02 You need to stop.

Answer 6

this argument has the form
if p then q.
q
--------------
p ,

this is invalid form

Answer 7

@perl Thank you!!!

Answer 8

But it is stating another idea...

Answer 9

this is actually a special kind of fallacy called asserting the consequence

Answer 10

http://en.wikipedia.org/wiki/Affirming_the_consequent

Answer 11

consequent*

Answer 12

and check out 'law of detachment' (also called modus ponens) http://en.wikipedia.org/wiki/Modus_ponens