An infinite regression is a proposed chain of causation in which each purported cause itself requires another event of exactly the same type to cause it.
This raises the question of what set the original chain in motion--in short, what was the "first cause." Whether all things must have a "first cause" or not, is a subject of debate.
Many scientists, observing the remarkable complexity of life (and especially of DNA, the molecule that holds the complete instruction set for life), doubt strenuously that life could have originated on the earth out of non-life--a process called abiogenesis. Francis H. Crick, the co-discoverer of DNA, recognized this early and also is alleged to have recognized other conditions that abiogenesis would have required, that in all probability did not exist on earth. Crick did not believe that life was created by supernatural means, and therefore deduced that since life did not originate on earth, it was deposited on earth from outside.
How, then, did this happen? Most proponents of his outside-seeding of life, called panspermia, suggest that the comets contain the seeds of life within their tails, and the earth acquired these seeds by passing through a comet's tail. Dr. Crick and his colleague Leslie H. Orgel assumed something far more radical: that an advanced civilization built and launched a brace of intergalactic ballistic missiles, each laden with bacteria and blue-green algae, in all directions from their homeworld. One such missile crash-landed on earth, and all life on earth is the by-product of the payload of that missile.
But this prompts two questions:
- Where did life originate, that it would then infiltrate multiple cometary tails?
- Did yet another advanced civilization fire the missile that provided the seed of life from which the most recent launch authority had its own origins?
Unless an eventual origin of life is proposed (on another planet or in space), then for each step, the observer must regress one age into the past. The problem is that he never stops regressing. An infinite regression cannot have an identifiable first cause.
Another Example: Who created the creator?
Another example of infinite regression is when one asserts that life must have been created, thus requiring a more complex creator. However, for this logic to hold, the creator is a life form which requires another life form to create it. This logic chain continues and causes an infinite regression.
Another method is to assume that the Creator is the First Cause and is the only Entity that is Past-Eternal (and Future-Eternal).
Classical illustrations of infinite regression
The oldest practical illustration of the concept of infinite regression requires the experimenter to erect two mirrors facing one another, and then to stand between them. He will see his own image looking back at him, and then the back of his own head, and then his face, and so on, an infinite number of times.
A more modern experiment requires a television camera and receiver. If one sends the signal from the camera to the receiver, and then aims the camera at the receiver, the receiver will show a picture of itself, holding a picture of itself, holding a picture of itself, holding a picture of itself, and so on to infinity.