Medical Ethics (Phil 164B)
Professor: Kristian Olsen
1) If I am cramming tonight, then I have an exam tomorrow
2) I am cramming tonight.
3) So, I have an exam tomorrow.
1) If I am not happy, then I am frowning.
2) I am not frowning.
3) So I am not, not happy.
The modus ponens that I wrote is valid because it fits the structure of a modus
ponens. In addition, it is a valid argument because the conclusion would be true if the
above premise were true. Also because the conclusion “follo