1. EPISTEMOLOGY Section 3

2. Descartes’ Doubt If it is possible that I am dreaming now, then I have reasons to doubt whether my current perceptual beliefs are true.

3. Descartes’ Doubt 1.If it is possible that I am dreaming now, then I have reasons to doubt whether my current perceptual beliefs are true. 2.It is possible that I am dreaming right now.

4. Descartes’ Doubt 1.If it is possible that I am dreaming now, then I have reasons to doubt whether my current perceptual beliefs are true. 2.It is possible that I am dreaming right now. 3.Therefore: I have reasons to doubt whether my current perceptual beliefs are true.

5. What is the form of this argument? 1.If it is possible that I am dreaming now, then I have reasons to doubt whether my current perceptual beliefs are true. 2.It is possible that I am dreaming right now. 3.Therefore: I have reasons to doubt whether my current perceptual beliefs are true.

6. What is the form of this argument? 1.If it is possible that I am dreaming now, then I have reasons to doubt whether my current perceptual beliefs are true. 2.It is possible that I am dreaming right now. 3.Therefore: I have reasons to doubt whether my current perceptual beliefs are true. 1.If p,

7. What is the form of this argument? 1.If it is possible that I am dreaming now, then I have reasons to doubt whether my current perceptual beliefs are true. 2.It is possible that I am dreaming right now. 3.Therefore: I have reasons to doubt whether my current perceptual beliefs are true. 1.If p, then q.

8. What is the form of this argument? 1.If it is possible that I am dreaming now, then I have reasons to doubt whether my current perceptual beliefs are true. 2.It is possible that I am dreaming right now. 3.Therefore: I have reasons to doubt whether my current perceptual beliefs are true. 1.If p, then q. 2.p.

9. What is the form of this argument? 1.If it is possible that I am dreaming now, then I have reasons to doubt whether my current perceptual beliefs are true. 2.It is possible that I am dreaming right now. 3.Therefore: I have reasons to doubt whether my current perceptual beliefs are true. 1.If p, then q. 2.p. 3.Therefore, q.

10. Modus Ponens 1.If it is possible that I am dreaming now, then I have reasons to doubt whether my current perceptual beliefs are true. 2.It is possible that I am dreaming right now. 3.Therefore: I have reasons to doubt whether my current perceptual beliefs are true. 1.If p, then q. 2.p. 3.Therefore, q.

11. Second Argument 1.It is impossible to distinguish with certainty between dream experiences and waking experiences.

12. Second Argument 1.It is impossible to distinguish with certainty between dream experiences and waking experiences. 2.If it is impossible to distinguish with certainty between dream experiences and waking experiences, then I cannot know whether I am awake right now.

13. Second Argument 1.It is impossible to distinguish with certainty between dream experiences and waking experiences. 2.If it is impossible to distinguish with certainty between dream experiences and waking experiences, then I cannot know whether I am awake right now. 3.If I cannot know that I am awake right now, then it is possible that I am dreaming right now.

14. Second Argument 1.It is impossible to distinguish with certainty between dream experiences and waking experiences. 2.If it is impossible to distinguish with certainty between dream experiences and waking experiences, then I cannot know whether I am awake right now. 3.If I cannot know that I am awake right now, then it is possible that I am dreaming right now. 4.Therefore it is possible that I am dreaming right now.

15. What is the form of this argument? 1.It is impossible to distinguish with certainty between dream experiences and waking experiences. 2.If it is impossible to distinguish with certainty between dream experiences and waking experiences, then I cannot know whether I am awake right now. 3.If I cannot know that I am awake right now, then it is possible that I am dreaming right now. 4.Therefore it is possible that I am dreaming right now.

16. What is the form of this argument? 1.It is impossible to distinguish with certainty between dream experiences and waking experiences. 2.If it is impossible to distinguish with certainty between dream experiences and waking experiences, then I cannot know whether I am awake right now. 3.If I cannot know that I am awake right now, then it is possible that I am dreaming right now. 4.Therefore it is possible that I am dreaming right now. 1.p.

17. What is the form of this argument? 1.It is impossible to distinguish with certainty between dream experiences and waking experiences. 2.If it is impossible to distinguish with certainty between dream experiences and waking experiences, then I cannot know whether I am awake right now. 3.If I cannot know that I am awake right now, then it is possible that I am dreaming right now. 4.Therefore it is possible that I am dreaming right now. 1.p. 2.If p, then q.

18. What is the form of this argument? 1.It is impossible to distinguish with certainty between dream experiences and waking experiences. 2.If it is impossible to distinguish with certainty between dream experiences and waking experiences, then I cannot know whether I am awake right now. 3.If I cannot know that I am awake right now, then it is possible that I am dreaming right now. 4.Therefore it is possible that I am dreaming right now. 1.p. 2.If p, then q. 3.If q, then r.

19. What is the form of this argument? 1.It is impossible to distinguish with certainty between dream experiences and waking experiences. 2.If it is impossible to distinguish with certainty between dream experiences and waking experiences, then I cannot know whether I am awake right now. 3.If I cannot know that I am awake right now, then it is possible that I am dreaming right now. 4.Therefore it is possible that I am dreaming right now. 1.p. 2.If p, then q. 3.If q, then r. 4.If p, then r (unstated) 5.

20. What is the form of this argument? 1.It is impossible to distinguish with certainty between dream experiences and waking experiences. 2.If it is impossible to distinguish with certainty between dream experiences and waking experiences, then I cannot know whether I am awake right now. 3.If I cannot know that I am awake right now, then it is possible that I am dreaming right now. 4.Therefore it is possible that I am dreaming right now. 1.p. 2.If p, then q. 3.If q, then r. 4.If p, then r (unstated) 5. Therefore, r