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The First-Cause Argument

From the ordered chain of efficient causes at work in the world to a first cause that depends on nothing else. Aquinas's Second Way — distinct from the argument from change: it asks not why things change, but why they exist and act at all, here and now.

Premises & Hinge

The Argument

The numbered form is ours, after Aquinas's Second Way; cf. Copleston, and the SEP, "Cosmological Argument" — the words themselves are the philosophers', below.

  1. P1 Whatever exists and acts is caused to do so by something else — an order of efficient causes.
  2. P2 Nothing can be the efficient cause of itself, for it would have to exist before it existed.
  3. P3 This chain of here-and-now (essentially ordered) causes cannot regress to infinity; without a first cause there would be no others. the hinge
  4. Therefore there is a first efficient cause, itself uncaused — to which everyone gives the name of God.

The sources

The Argument Saint Thomas Aquinas 1268
The second way is from the nature of the efficient cause. In the world of sense we find there is an order of efficient causes. There is no case known (neither is it, indeed, possible) in which a thing is found to be the efficient cause of itself; for so it would be prior to itself, which is impossible. Now in efficient causes it is not possible to go on to infinity, because in all efficient causes following in order, the first is the cause of the intermediate cause, and the intermediate is the cause of the ultimate cause, whether the intermediate cause be several, or only one. Now to take away the cause is to take away the effect. Therefore, if there be no first cause among efficient causes, there will be no ultimate, nor any intermediate cause. But if in efficient causes it is possible to go on to infinity, there will be no first efficient cause, neither will there be an ultimate effect, nor any intermediate efficient causes; all of which is plainly false. Therefore it is necessary to admit a first efficient cause, to which everyone gives the name of God.

Source — Saint Thomas Aquinas, Summa Theologica I, q. 2, a. 3 — the Second Way (from efficient cause)

Objection Saint Thomas Aquinas 1268
It is superfluous to suppose that what can be accounted for by a few principles has been produced by many. But it seems that everything we see in the world can be accounted for by other principles, supposing God did not exist. For all natural things can be reduced to one principle which is nature; and all voluntary things can be reduced to one principle which is human reason, or will. Therefore there is no need to suppose God's existence.

Source — Saint Thomas Aquinas, Summa Theologica I, q. 2, a. 3, obj. 2 — the objection that God is superfluous

Reply Saint Thomas Aquinas 1268
Since nature works for a determinate end under the direction of a higher agent, whatever is done by nature must needs be traced back to God, as to its first cause. So also whatever is done voluntarily must also be traced back to some higher cause other than human reason or will, since these can change or fail; for all things that are changeable and capable of defect must be traced back to an immovable and self-necessary first principle.

Source — Saint Thomas Aquinas, Summa Theologica I, q. 2, a. 3, reply to obj. 2 — the reply that nature is traced back to God

Objection David Hume 1779
In such a chain, too, or succession of objects, each part is caused by that which preceded it, and causes that which succeeds it. Where then is the difficulty? But the whole, you say, wants a cause. I answer, that the uniting of these parts into a whole, like the uniting of several distinct countries into one kingdom, or several distinct members into one body, is performed merely by an arbitrary act of the mind, and has no influence on the nature of things.

Source — David Hume, Dialogues Concerning Natural Religion, Part IX (Cleanthes)

Argument hinges on:

The chain of here-and-now causes This chain of here-and-now (essentially ordered) causes cannot regress to infinity; without a first cause there would be no others. What does that mean?
The library's note

The Second Way is easy to confuse with the argument from change, but it asks a different question. That argument asks why a thing moves or alters; this one asks why it exists and acts at all — right now, this instant.

Consider the light in a room. It shines only because current is flowing through the bulb; the current flows only because the generator is turning; and so on. This is not a story about the past — it is all happening at once, and the light depends, this very moment, on every link below it. Cut the current and the light is gone instantly. Aquinas calls a chain like this essentially ordered: each member has no power to cause on its own, but only as it receives that power, now, from the one before it.

Such a chain cannot go back forever, because if every member were only passing along causal power it borrowed, with no first member actually supplying it, there would be no power in the chain and nothing would be lit. Yet the light shines. So there must be a first cause that is not itself being caused. And nothing, Aquinas adds, can be the cause of its own existence, since it would have to be there before it was there to do the causing.

The most memorable modern reply is Bertrand Russell's, in his 1948 radio debate with the Jesuit Frederick Copleston: pressed for the cause of the universe, Russell answered, "the universe is just there, and that's all." Critics also charge a fallacy of composition — that even if each thing has a cause, the whole collection of things need not. Copleston's reply was that an essentially ordered, here-and-now dependent series is exactly the kind that does require a first member. Whether it does is where the argument lives.

Written for this library — not a quoted source. It reports how the premise is argued and answered; the philosophers' own words are above.

If you accept it

Accept that a here-and-now causal series must have a first member, and — the fallacy-of-composition charge runs — you may be illicitly treating the whole collection of causes as one more thing that itself needs a cause.
Bertrand Russell; Graham Oppy ↗

The reply

The distinction defenders press is between a chain running back through time, which may be endless, and one acting all at once, where every later member depends on a member acting now.
Edward Feser, Five Proofs of the Existence of God (2017) ↗

If you deny it

Deny it, and you may stop with the world itself as a brute fact — "the universe is just there, and that's all" — but then the ordinary demand for a cause, honoured everywhere else, is simply switched off at the last step.
Bertrand Russell, in the 1948 debate with F. C. Copleston ↗

Where it leads

Accept that a chain of here-and-now causes cannot regress forever, and this argument leads to a first efficient cause, itself uncaused.

Beyond the public domain

The modern revivals and their critics are under copyright, so we don't host them — the reading doesn't stop at the public-domain record. Follow it at the sources:

Stanford Encyclopedia of Philosophy — Cosmological Argument Edward Feser, Five Proofs of the Existence of God (2017) — the existential proof The Russell–Copleston debate (BBC, 1948) — the exchange and transcript

You have read the premise, the objection, and the cost of each move. The library draws no conclusion.