Philosophy 5320-02: Cosmological and Ontological Arguments

Continually being revised as the semester progresses.

Instructor: Alexander R. Pruss
Class times: Tuesdays and Thursdays, 12:30-1:50 pm, MH 108
Office hours: Monday, Wednesday and Friday, 10:00 am-11:00 am, MH 213
Course website:


Cosmological Arguments start with a very general feature of the world, say the existence of something rather than nothing or the fact that there is motion, and argue that this feature is to be explained in theistic terms, in terms that involve a First Cause. Cosmological Arguments thus are a posteriori, but the feature of the world that they are based on tends to be highly general and uncontroversial. Ontological Arguments, on the other hand, strive to show on purely conceptual grounds that there must be a God, typically conceptualized as a being than which no greater is possible.

In the latter half of the 20th century, significant progress has been made both in precisely formulating these arguments and in identifying criticisms of these precisely formulated arguments. While Cosmological Arguments are typical of philosophy, i.e., their success is the subject of much controversy (whether it should be the subject of controversy is a different question), it is widely acknowledged that no Ontological Argument is successful, though in the case of most instances of the Ontological Argument, there is disagreement about why it fails. Nonetheless, we shall consider two recent attempts to make an Ontological Argument work by bringing in a posteriori premises to demonstrate a logical point.

Tentative topics

  1. Kalaam arguments (Al-Kindi, Craig)
  2. Aquinas' arguments
  3. Clarke's argument
  4. Hume's replies (Hume, Rowe, Smith, Pruss)
  5. The Principle of Sufficient Reason (PSR)
    1. van Inwagen's objection (van Inwagen,
    2. Arguments for the PSR (Koons, Pruss)
  6. Less than the PSR (Koons, Gale, Pruss)
  7. The gap problem
  8. Standard ontological arguments: Anselm, Descartes, Leibniz and Godel (Oppy's book)
  9. Samkara's Principle (Pruss)
  10. Desire and the Ontological Argument (Buras)


  1. Graham Oppy, Ontological Arguments and Belief in God (do not but this before I know how much of it we want to use; maybe photocopies of small parts will do).
  2. Alexander Pruss, The Principle of Sufficient Reason: A Reassessment, excerpts (I may have to have you buy the book--legal stuff has to be checked).
  3. Various articles put out for you to borrow and photocopy.

The specific readings will typically be announced two classes in advance, and will in fact be listed in the online version of this syllabus.

Lecture notes



Typically, each student taking the class for credit will write a paper each week. The paper will be handed in at the beginning of one of the two classes that week, and the student will be prepared to present it for class discussion (bring an extra copy for yourself to read, if you want to read; I will want one to follow along and make notes on). The paper is 1.5-2.5 pages long, and consists of a brief but clear exposition of some argument from the reading together with an argumentative response (critical or constructive). The ideal is a paper in the journal Analysis.

On at most one occasion (as well as in cases of reasonable personal distress), a student may combine the paper assignments from two successive weeks into a single, unified 4-5 page paper. On at most two occasions, the paper can relate to the reading or discussion of the immediately preceding class instead of the reading for the class during which it is handed in.

I would like to ask that not all of your papers be handed in on Thursdays, tempting as that may be.