PHIL/RS 335
Arguments for God’s Existence Pt. 1: The
Cosmological Argument
Going back to the beginning.
 The cosmological argument has its origin in
Ancient Greek Philosophy.
 We see versions of the argument in the work of
both Plato and Aristotle.
 There, of course, the argument was not aimed at
proving the existence of a theistic divinity, but at
explaining the origin of the world.
The CA in the History of
Philosophy
 In the forms more familiar to us, the aim of the argument is
proving the existence of the God of the traditional
monotheisms.
 Historically, there are two periods of particularly intense
interest in the cosmological argument.
 The first is in the 13th century, due to the influence of Thomas
Aquinas, whose first 3 proofs for the existence of God in the
section of the text entitled “The Five Ways,” are various versions
of the cosmological proof.
 The second is in the 18th century, when the work of two
prominent advocates of the argument, Leibniz and Samuel
Clarke was at the zenith of its influence.
 Though there continue to be advocates of versions of the
CA, most contemporary philosophical theists have voiced
skepticism about the argument.
What is it?
 As should already be apparent, the
cosmological argument is really a family of
arguments which share a basic structure.
 Though there are significant variations which we
will have to account for, the various versions of
the CA begin with certain relatively noncontroversial descriptions of the natural world
and infer from them the existence of a necessary
being, which they then argue must be
understood as God.
Aquinas’s Five Ways
 As already noted, only the first three arguments
offered by Aquinas are versions of the cosmological
argument.
1. Argument from Motion
2. Argument from Efficient Causality
3. Argument from the Existence of Contingent Beings
 An examination of these three arguments reveals a
common set of elements.



They are all a posteriori arguments, starting with
observation and reasoning to conditions.
They all assume the impossibility of infinite regress.
Strictly speaking, they don’t quite get us to God, but
rather, to what, “…everyone understands to be God.”
Evaluation of these elements.
 The class of arguments we are calling a posteriori
arguments are common and generally non-controversial,
though they are most frequently developed as inductive,
rather than deductive arguments.
 The claim of the impossibility of infinite regress is much
more controversial. Copleston, in the inset on p. 62, tries to
rescue this claim by insisting that Aquinas’s assertion is an
ontological rather than temporal or genetic claim, but
set-theoretic mathematics provides the resources for
serious reservations here.
 The point of the last observation is to highlight that even if
we grant the force of the arguments offered by Aquinas,
we don’t seem to get the God of theism. We might get a
first mover, a first efficient cause, or a necessary being,
but not the loving, personal God which traditional theism
is committed to.
A More Modern Version
 Both Leibniz and Clarke combined an attempt to use the principle of
sufficient reason to establish the existence of a self-existent being and
then argue that such a being is best understood as the God of theism.
 The first step in the argument can be summarized as follows.
1.
Every being is either a dependent being or a self-existent being.
2.
Not every being can be a dependent being.
__________________________
Conclusion: There exists a self-existent being.
 Definitions

Dependent Being: a being whose existence is accounted for by
the causal activity of other things.

Self-Existent Being: a being whose existence is accounted for by its
own nature (what the Yandell’s refer to as “existential security”).
Explanation of Premise 1
 For Leibniz and Clarke (and the Yandells) the
truth of the first premise is established by the
Principle of Sufficient Reason.
 The PSR is commonly formulated as “Everything has
a reason,” though it can be formulated in a number
of more specific ways (see 69c2). What does this
mean? There are a number of possibilities.
 There must be an explanation a)for the existence
of any being; b)of any positive fact whatsoever
(73c2); c)of the cosmic whole.
Explanation of Premise 2
 There are two ways commonly employed to
establish the second premise.
 The first is Aquinas’s: there can be no infinite series.
 The second is the assertion that there are no brute
facts. That is, there has to be an explanation of why
there is anything at all (82c1).
 Consider the following causal chain
A1—A2—A3—An—An+1
 Relative to any A, the PSR is satisfied, but what about
the chain as a whole?
 Only the assertion of the second premise would
seem to satisfy the PSR for the chain.
Criticisms of the 2nd Premise
 Makes a category mistake. Assumes that the series
is of the same ontological order of the elements of
the series.
 Commits the Part/Whole Fallacy. All humans have
mouths, but that doesn’t mean that the category
“human being” has a mouth.
 Hume, Dialogues Concerning Natural Religion, Pt.
IX, “Did I show you the particular cause of each
individual in a collection of twenty particles of
matter, I should think it very unreasonable, should
you afterwards ask me, what was the cause of the
whole twenty. This is sufficiently explained in
explaining the cause of the parts.”
Criticisms of Premise 1
 Why should we accept the PSR?
 Is it intuitively true? Does reason presuppose it? If an explanation seems
possible, does that mean there is one (Yandells 76c1)?
 Mackie identifies a number of arguments which call these justifications
into question (79c2-81c2).
1. Contra Clarke, the PSR doesn’t seem to fit with what we know of human
behavior.
2. What about the requirements of reason? Scientific inquiry (philosophical
or otherwise) requires causal inquiry of the intra-series sort, but all such
inquiry begins in posits, and these don’t seem to require the PSR.
3. What about purposiveness? We often desire that there be an absolute
purpose, but surely thinking of our lives as purposeful doesn’t require an
absolute purpose.
 “We have no right to assume that the universe will comply with our
intellectual preferences” (81c2).
 See also the Rowe inset on p. 80.