(June 21, 2016 at 2:28 am)IATIA Wrote: Fish have scales
Snakes have scales
Therefore snakes are fish.
Neither valid nor sound. Because the truth of the premises don't guarantee the truth of the conclusion, it's not even valid.
The modal ontological argument is valid because if premise 1 is true, then everything else stated in the argument must follow, under modal logic. So the matter becomes about whether the argument is sound or not.