Consider the following argument from analogy. According our rules for appraising analogical reasoning, if a subsequent consideration strengthens the argument, answer a. Answer b if a consideration weakens the argument. Answer c if a consideration does not affect the argument. Bill has taken three history courses and found them very stimulating and valuable. So he signs up for another one, confidently expecting that it too will be worthwhile.

25. Suppose that his previous history courses were in ancient history, modern European history, and American history.
26. Suppose that his previous history courses had all been taught by the same professor that is scheduled to teach the present one.
27. Suppose that his previous history courses all had been taught by Professor Smith, and the present one is taught by professor Jones.
28. Suppose that Bill had found his three previous history courses to be the most exciting intellectual experiences of his life.
29. Suppose that his previous history courses had all met at 9:00am, and the present one is scheduled to meet at 9:00am also.
30. Suppose that, in addition to the three history courses previously taken, Bill also had taken and enjoyed courses in anthropology, economics, political science, and sociology.