LECTURE #2: Introduction to the Cosmological Argument


I. Why is the cosmological argument important?

II. The Basic Form of the Cosmological Argument

III. Variations on the Theme

IV. Metaphysical Background
A. Potency & Act, Essence and Existence
B. Impossibility, Necessity, and Contingency

I. Why is the cosmological argument important?

There is an interdepency between the cosmological argument (the argument to a first cause) and the design argument (the argument to a cosmic designer/creator). The two arguments are much stronger in tandem than they are when taken individually. We will look at this in more detail when we consider the design argument, but I want to foreshadow that discussion before launching into the cosmological argument.

If the cosmological argument is successful, it provides the means for answering certain important objections to the design argument. For example, a common and serious objection to the design argument is the threat of an infinite regress. The world is highly organized, so we infer a designer. But, every intelligent designer we know (i.e., human beings) are themselves highly organized systems. So, it seems that we need to infer a designer of the designer, and so on to infinity. Apparently, we haven't gained anything, so we should stop at the first step, and assume that the cosmos has no designer.

The cosmological argument, if successful, provides a powerful reply to this objection. The cosmological argument tells us that there is an uncaused first cause of the world. If the world bears the signs of intelligence, it is reasonable to attribute intelligence to the first cause. There is no threat of infinite regress, because we know that the first cause is uncaused. It provides the natural stopping point.

Secondly, the results of the cosmological and design arguments are complementary. As we shall see, the cosmological argument gives us good reason to infer that the first cause has such characteristics as eternity, infinity, unity and necessity. It gives us much weaker reasons, if any, for thinking that the first cause is personal, intelligent or purposeful. In contrast, the design argument gives us good reason to attribute intelligence and purpose to the creator, but it gives us little reason for assuming that the creator is eternal or infinite. Each argument tends to make up the deficiencies of the other.

II. The Basic Form of the Cosmological Argument

As we shall see, the cosmological argument has a long history, beginning with Plato and Aristotle, running through the medieval philosophy of Arabs, Jews, and Christians, and continuing into modern philosophy through Descartes and Leibniz. In addition, a number of 20th century philosophers have defended the argument. Despite this long history, all of the arguments are variations on a single theme. The common form goes something like this:

1. Everything of type X has a cause.
2. There is something of type X.
3. For some reason (namely, Y), the series of causes of an X must terminate in a first cause.
4. This first cause can be identified with God.

The variations on this form come about in three different ways. First and second, different versions fill in the variables X and Y in different ways. Third, there are a number of different conceptions of "cause/effect" that are employed in the arguments. These conceptions of causation vary in two different ways. Consequently, there are four different dimensions of variability to consider. The various arguments that result are not necessarily incompatible. It is quite possible that there are a number of different cosmological arguments, each valid, and all converging on compatible and complementary results. Most philosophers will champion one or another of the arguments as the best or most fundamental, but we shouldn't be too quick to assume that there is only one form on which all the others depend.

III. Variations on the theme

As I sketched in the last section, there are four parameters or dimensions of variability. These are:

1. Focus. What is the X? What type of things are supposed to need a cause?

2. Rationale. What is the reason Y? Why must a series of causes terminate in a first cause?

3. Temporality. What is the relationship between causation and time? Do causes always precede their effects, are they always simultaneous with their effects, or is causation independent of time?

4. Modality. Do causes make their effects necessary, or only possible or likely? Do causes necessitate or only incline?

Let's take each of these parameters one at a time.

Focus. Historically, there are three things that have been taken to be the focus of causation: motion/change, the actualization of a potential, and the existence of some thing with an essence or nature. The oldest arguments, including those of Plato and Aristotle, were concerned primarily with motion or change. The Latin word 'motion' (and the related Greek word 'kinesis') included more than just locomotion. Any change in the quality of a thing or its real relations to other things constituted a form of 'motion', e.g., getting hotter, heavier, beginning to glow, beginning to perceive something, thinking actively, as well as moving in space. We can think of every case of change as being an event or a process, and every event or process involves some change. So, the first specification of focus can also be thought of as insisting that every event or process requires a cause.

When we move to the actualization of potential, we are including static conditions or states within the focus group, so long as the state is accidental, that is, so long as it is not an essential or necessary feature of the thing. Suppose that there is an infinitely old and unchanging black hole in the cosmos, and suppose that this black hole has a mass of exactly 1 billion times the mass of our sun. Black holes can have a variety of mass-values, so it is not essential to this black hole that it have exactly this mass. It seems that it could have had slightly more or slighly less mass. If this is so, the potential mass of this black hole includes a range of values, only one of which has been made actual. Even though there has been no change in the mass of the black hole, we might think that there must be some cause of its having the mass that it does -- that something must have actualized its potential of having exactly 1 billion sun-masses.

The third focus group is that of all things that exist accidentally -- whose existence is not a matter of absolute and intrinsic necessity. For example, suppose the archangel Michael exists eternally without any change, and suppose that all of Michael's characteristics are essential to him qua archangel. There is nothing about him that cannot be explained by reference to his archangel-hood. Nonetheless, it is quite possible for there never to have been an archangel at all. The world could have been entirely archangel-less. Michael's existence is accidental, and it seems reasonable to look for a cause of that existence.


Almost all versions of the cosmological argument start with the assumption that causation is transitive and asymmetric. That is, if A causes B, and B causes C, then A causes C, and if E causes F, then F cannot cause E. These two properties of causation guarantee that there can be no causal loops or cycles. Consequently, there are only two kinds of series that are possible: those that terminate in a first cause (uncaused cause), and those that regress to infinity, without looping or stopping. There are three reasons for thinking that every series must end in a first cause.

First, one might be a finitist. A finitist believes that the real world contains only finitely many things. If there are only finitely many things, there cannot be any infinite series of any kind, so there cannot be any infinite causal regresses.

Second, one might take no position on whether there are infinite series, but one might think that an infinite causal regress is for some special reason impossible. I'll call this position the anti-regressive position.

Finally, one might argue that, even if there are infinite regresses, the infinite regress must itself be caused by something uncaused. This argument is typically carried out by arguing that we can aggregate all of the X's (where the X's could be events and processes, accidental states, or contingent existences), and that the aggregate itself must have a cause that lies outside the aggregate. For example, the aggregate of all contingent things is contingent, and we could argue that the aggregate must have a cause, and this cause must be non-contingent (since it lies outside the aggregate), and so the cause is itself uncaused, a termination point. This position I will call the aggregative view.


There are different conceptions of the relationship between causation and time. The first holds that causes are always earlier than their effects. This is the diachronic view (dia-chronic means through time). The second holds that causes are always simultaneous with their effects. This is the synchronic view (synchronic = together in time). Finally, one could hold the achronic view, the view that there is no necessary relationship between causation and time.

It is possible to combine all three views, by holding that there are three different kinds or forms of causation: diachronic, synchronic and achronic.


Some philosophers, especially those influenced by neo-Platonism, have held that causes necessitate their effects, that is, given the existence of the cause, the effect must happen: there is no possibility of the effect failing to follow. This position is held explicitly by Ibn Sina (Avicenna) and by Leibniz. Leibniz formulates a principle of sufficient reason: for every fact, there is a sufficient reason that explains why that fact had to be so, rather than any other way.

Many others have held that causes make their effects possible or likely, but do not bring about their effects with necessity. Someone who believes in a strong version of divine freedom must hold this view. God's essence may have inclined him to create a certain kind of world, but nothing necessitated that he do so. Some of the Arab philosophers were very explicit on this point. Holding that time is eternal but that the universe was created at a particular moment, the Arab philosophers of the Kalam tradition were faced with the problem of explaining why God created when he did, rather than earlier or later. Their answer is that nothing necessitated God's creating when he did. God's being is the cause of the existence of the world at the point in time of creation, but nothing necessitated that this effect occur at this time.