Trains and Chains and God as First Cause


Trains and chains are popular analogies used to illustrate the argument for a First Cause, whom we call God. See: Reasons to Believe (p. 32) by Scott Hahn, Answering Atheism (p. 236) by Trent Horn, Who Designed the Designer? (p. 34-37)  by Michael Augros, and, most recently, “What Caused God” by Trent Horn.

But is the concept of a causal chain of any value to an argument for the existence of God, or even to philosophy in general? This essay will note what happens to the analogies and to the basic philosophical argument when effect and cause are defined compatibly with these analogies.

The Train and Chain Arguments

The gist of the train and chain First Cause arguments is evident in two quotes from Horner:

  • “a boxcar’s motion can be explained only by something that is not itself a boxcar”
  • “if you got rid of any link in the chandelier chain, the whole thing would come crashing down”

The “train argument” identifies the cause of the motion of the caboose as the boxcar to which it is coupled and so on through a series of causes, i.e. boxcars, which must terminate with a locomotive, which explains its own motion and is thus, the first cause of the motion.

Similarly, the “chain argument” identifies the cause of the suspension of the chandelier as the link of the chain immediately connected to it and so on through a series of causes, i.e. chain links, which must terminate in something, which due to its construction, is not suspended and is thus, the first cause of the suspension. Augros, for example, proposes the ceiling I-beam of a structure as the first cause.

In summary: When you ask, “What caused this?” you naturally progress up the causal chain until you are left with only two options: a causal chain that is infinite or a chain that terminates with a final, “uncaused” cause. This is true both for temporal causal chains and hierarchical causal chains.

The Two Self-Evident Principles

  • Things exist.
  • Everything is intelligible, i.e. everything makes sense. This principle is sometimes identified as the principle of sufficient reason.

If one were to deny either of these principles, human intellectual knowledge would be impossible and there would be nothing intellectual to communicate to another human being.

The Definitions of Effect and Cause

An effect is that which does not fully explain itself. A cause is the other, which does explain an effect. In order to be a cause, it must be its own justification.

A cause and its effect must be of the same type and level. There are four types of causes: material, formal, efficient, and final or purposeful. There are different levels within causes. A formal cause, for example, may be at the level of substance or at the level of the property of a substance. An efficient cause, likewise, may be at the level of existence or at the level of local motion.

Application of the Definitions

It should be apparent that a cause must not only serve as a necessary explanation but also serve as a sufficient explanation of an effect. If that which is viewed as the prospective cause is not a sufficient explanation in accord with the type and level of the causality, it would not be the cause of the effect. It could be a necessary factor, and in that sense, a secondary cause, but it would not be the cause. Identifying a factor as simply necessary in explaining the effect leaves the search for the cause of the effect still in progress. Of course, a set of necessary, but individually insufficient factors may be sufficient as a set. This is common in cases that are the object of study by the physical sciences. However, such sets are not linear regressions.

For trains, each boxcar is not the cause, i.e. both necessary and sufficient, to explain the motion of its coupled boxcar or the caboose. For chains, each link is not the cause, i.e. both necessary and sufficient, to explain the suspension of its adjacent link or the suspension of the chandelier. These sequences, formed by coupling or linking, are not sequences of causes.

The argument that a regressive series of causes must terminate in a First Cause serially identifies as logical the acceptance of the insufficient as sufficient. In only the terminal instance is it acknowledged that to be an explanation, an explanation must be sufficient.

God, as First Cause, is Immediately So

Local motion is characteristic of material things. So too, structure is characteristic of material things. Causality at these levels, namely local motion and structure, is fully explained at these levels of causality. The natures of material entities explain all of their material properties, including local motion and structure. The nature of a material entity is necessary and sufficient to explain everything about it with one exception, its existence.

The existence of a material entity, e.g. this cat, must be caused by other than this cat. That being cannot have the same existential flaw, which requires this cat to have another being as the cause of its existence. The existential flaw is that the cat’s nature is distinct from the cat’s existence. That is why its nature explains everything about the cat but its existence.

Where the effect is existence, the cause, in order to be the sufficient cause of the existence of another, must be an entity whose nature is its existence. Its nature would then not be indifferent to existence as is the nature of everything within our experience. Its nature must be To Exist. In revealing himself to Moses, this is how God identifies himself: “I am” (Exodus 3:14). In this being that we call God, there can be no distinctions of property and no distinction between nature and existence, else His nature would not be To Exist. Due to his uniqueness and due to his causing the existence of another (such as this cat), God’s causality of the other’s existence must be immediate. The alternative would be that God created an intermediate being, which is naturally and existentially indistinguishable from himself. That is a self-contradiction.


The properties of material things are related by their common characteristic of extension. Consequently, material things may be viewed as related to one another in networks and in linear sequences through their properties, i.e. at the causal level of property. Properties are subordinate to substance in causality because they exist in substances. In contrast, a substance or entity exists in itself, not in another.

Because God is the immediate cause of the existence of each created entity, he is the First Cause of its existence, in the sense of sole and immediate. Thus, to discuss sequences as having any relevance to the existence of God is inane, even if it is conceded for the sake of argument that there could be no infinitely regressive series involving material properties.

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2 thoughts on “Trains and Chains and God as First Cause”

  1. Pingback: Causality and St. Thomas Aquinas’ Second Way - Catholic Stand : Catholic Stand

  2. Pingback: Is God, as First Cause, a Numerical First of Many Causes? | theyhavenowine

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