So if I say, "All giraffes are green. The sun is a type of giraffe. Therefore, the sun is green," that argument would be valid but not sound?
Hi HM, I believe that I misread your statement.
It doesn't follow a formal deductive structure so I would argue that it isn't valid or sound.
One of the correct modus ponens structures:
(1) If A, then B.
Your argument would follow this structure if you stated that : All giraffes are green, the sun is green. The Sun is green, therefore the Sun is a giraffe. There are also other variants of this argument which are internally valid. (i.e. the conclusion follows from the premises, not necessarily based on truth).