The Carl Sagan Proof for the Christian God

Carl Sagan, a famous science apologist, science popularizer and agnostic, once said that extraordinary claims require extraordinary evidence. He used this as the concise reason for his effective atheism.

But I think we may take this oh-so-often-quoted-by-atheists “principle” and, in a Judo-like philosophical move, apply it to prove not only God, but the Christian conception of God. We’ll proceed in four easy steps from atheism or agnosticism to Christian belief. Here we go:

Step One: Atheism to Deism

Let’s begin with Mortimer Adler’s Proof for the Existence of God:

1. The existence of an effect requiring the concurrent existence and action of an efficient cause implies the existence and action of that cause.
2. The cosmos as a whole exists.
3. The existence of the cosmos as a whole is radically contingent (meaning that it needs an efficient cause of its continuing existence to preserve it in being, and prevent it from being annihilated, or reduced to nothing).
4. If the cosmos needs an efficient cause of its continuing existence, then that cause must be a supernatural being, supernatural in its action, and one the existence of which is uncaused, in other words, the Supreme Being, or God.

Conclusion: The Supreme Being, or God, exists.


Carl Sagan, Noted Twentieth Century Scientist and Agnostic

Adler’s proof is a version of the cosmological argument, most famously articulated by Saint Thomas Aquinas. Now while we might dispute with Adler whether premises (2) and (3) are necessarily true, if we apply Carl Sagan’s extraordinary evidence principle, we must come to the conclusion that they hold. For premise (3) to not hold, we would need to live in a universe that could not possibly be otherwise than it is, for this would be a cosmos of non-contingent beings. That is to say it must, in that case, be logically impossible, as impossible as there being a four sided triangle, by definition impossible, for anything at all, the weather, the President of the United States, the bus accident that killed my great aunt, everything, to have been otherwise than it is or than it happened. Now, in order for us to accept that claim as true, it would require some extraordinary evidence. Which we do not have. No, for all the world, it would appear that the world could be otherwise. It’s just not. It just happens to be the way it is. Therefore, unless you’re a Buddhist and wish to seriously deny premise (2), or unless you wish to deny Sagan’s Principle, Adler’s Proof holds and there is a God.

Let’s say you deny premise (2), if I told you that you don’t exist, wouldn’t you require some extraordinary evidence to be convinced of that claim? So Adler’s Proof, fortified with Sagan-logic, holds, and there is a God.

Step Two: Deism to Personal Theism

Mortimer Adler, Jewish Twentieth Century Philosopher, Educational Reformer, and Convert to Christianity and Catholicism

But what kind of God is this? Aristotle himself believed in a God that would satisfy Adler’s Proof, but it isn’t anything like the Christian God, or even the Muslim God. Aristotle’s God was completely impersonal, and more like a force of nature (just a completely uncaused Ultimate one) than a person. It would make no sense, for example, to pray to such a deity, since it would be unable to hear or even to understand your prayers.

But once again Carl Sagan comes to our rescue. Now it is easy to see how a Personal God could create Personal creatures like you and me with consciousness. Not easy per se because we do not understand what goes into consciousness or forming a consciousness, but I mean we can conceive how a being analogous to ourselves could say to himself, “I would like to create conscious beings who experience a mental life.” So let’s create a similar argument to the one from Step One:

1. Conscious, intelligent beings exist.
2. The existence of intelligent consciousness (or self-awareness) is radically different from physical existence, and no merely physical process can produce self-awareness.
3. If the only known way to produce conscious beings is from other conscious beings, then having established a Supreme Being exists, this Supreme Being would have to be conscious, and confer in some manner consciousness to other conscious creatures.

Conclusion: The Supreme Being, if He or It exists, is conscious and intelligent, is a He, not an It.

Now once again, premise (2) is suspect. But let’s apply Sagan-logic: There are absolutely no examples in our everyday lived experience of consciousness coming from non-consciousness. No, in our experience, conscious beings only come from other conscious beings (another way of stating premise (2)), and furthermore, when conscious beings in our experience are even removed from the company of other self-aware intelligent beings for an extended period of time, they inevitably go insane. Therefore, if we follow in the path of Sagan, we may safely hold that it is true that, if the Supreme Being exists, he must be conscious, because we have many concrete examples of conscious beings creating consciousness (and experience is arguably the best evidence there is), but there are no confirmed examples of conscious intelligent beings arising from mere matter. An extraordinary claim like a conscious intelligent being arising from mere matter requires extraordinary evidence that we do not have. No human being has ever witnessed it to happen. We cannot even conceive how it could happen. So (good Sagan-style agnostics that we are) we must assume that it doesn’t happen, and therefore, there is a self-aware, intelligent, conscious Supreme Being.

But wait, you say. You just said that in our experience, intelligence cannot exist outside of a community. Wouldn’t that imply, by Sagan-logic, that we should believe a single personal God does not exist, but he would need to live in a community of gods?

Step Three: Personal Theism to Multi-Personal Theism

There can only be one Supreme Being, because there can only be a single uncaused cause, not two. For if there were two uncaused causes, eternal, having existed since the world began, it would be more proper to call them one Supreme Being, or we might postulate them as aspects of the Supreme Being, or perhaps Persons of the Supreme Being, since they always existed together in cooperation, and neither caused the other to begin to exist in time.

Having established, then, by Sagan-logic that a personal God exists, we can further lay out the following:

1. Conscious intelligent persons only exist in communities of other conscious intelligent persons and soon descend into madness and irrationality if removed from their communities.

2. God (if He exists) exists as at least one intelligent Person. (established in Step Two above)

Conclusion: God (if He exists as an intelligent Being) exists as a community of multiple intelligent Persons.

Now can we absolutely prove premise (1) above? We can with Sagan-logic. It is an ordinary thing to see conscious intelligent persons in community, but it would be extraordinary to come into contact with one that had never been in contact with any other, that never required another intelligent, self-aware person. In fact, all of the evidence points towards the conclusion that consciousness cannot exist apart from community. To disprove it, we would need extraordinary evidence. Lacking that extraordinary evidence, it is only logical to conclude that Step Three is valid.

Step Four: Multi-Personal Theism to Christianity

Now to my knowledge the only major religion that proposes such a God is Christianity. Ironically, the Trinity is often proposed by critics as one of the reasons Christianity is irrational. But wouldn’t it be an extraordinary claim if an intelligent, multi-personal God exists, and Christianity happened to be correct by postulating such a God, completely by chance?

1. Christianity uniquely postulates the existence of a Multi-Personal God.

2. A merely human religion, without revelation from a Multi-Personal Supreme Uncaused Being, would not correctly guess that a Multi-Personal Supreme Uncaused Being exists.
Conclusion: Christianity is revealed by God to humanity.

Again, we might doubt that premise (2) is necessarily true, but Carl Sagan, that stalwart defender of sweet Reason, has our answer. Because we have no evidence that a merely human religion would correctly guess that God exists as a multi-personal being, indeed, such evidence would need to be extraordinary for us to believe it, we must conclude that a merely human religion would not guess this aspect of the nature of God.


And so we arrive at the interesting conclusion. If you cannot demonstrate that:

1. The universe could not possibly, consistently, be different than it is.

2. Conscious, intelligent, self-aware beings can arise from mere matter without other conscious, intelligent, self-aware beings directing their creation or begetting them.

3. Conscious, intelligent, self-aware beings can exist independently of, without any contact with, other conscious, intelligent, self-aware beings.
4. A merely human religion would be likely to correctly guess unaided by Reason that only one God exists, and He exists as a multi-personal Being…

If you don’t buy that, and if you can’t provide extraordinary evidence for those extraordinary claims, each of which has never been proven or witnessed by anyone living, then you must conclude, by Carl Sagan’s logic, that God exists as a Multi-Personal Supreme Being, and Christianity is true.

I can imagine someone saying, “Fine, a Multi-Personal God created the Universe and He also created intelligent, conscious, self-aware beings like ourselves and like Himself. But Christianity still is not necessarily true because I accept premise (4) immediately above: Surely among all of the religions that have ever existed, one is likely to have stumbled upon the correct answer. Maybe the Multi-Personal God who created the Cosmos, the Supreme Good, has no interest in interacting with humanity aside from holding them (along with the rest of Creation) in existence from moment to moment and watching them suffer pointlessly their meaningless, short lives until they pop out of existence at their deaths.” Well, I don’t think that’s a terribly likely conclusion myself. But now that, having been persuaded by Carl Sagan, purely through the operation of sweet Reason, you are a Multi-Personal Theist, let me tell you about a man named Jesus of Nazareth…


As I hope this article makes clear, the extraordinary evidence that Carl Sagan was looking for stood right in front of him every morning… in his bathroom mirror. Try Step One on your atheist or agnostic friend next time you see him, and see how it goes. What are your experiences with Christian evangelization?

Note on Dualism, Zoroastrianism, and similar religions: Denying premise (1) of Step Four above, someone might counter that Dualism is another religion that could be construed to postulate a multi-personal God, eternal and uncaused, albeit one with Persons at eternal war with each other. However, this religion (all the formulations I have heard of) states that one of the deities is good and the other evil. As another C. S. points out in Mere Christianity, to do so places the deities in question in subjection to a higher principle, namely the Good. In such a case, these deities could not both be Supreme, but The Good would be Supreme, as evil is merely a deprivation of Good and has no independent existence of its own. Only a cooperative community of God, whose nature is The Good, makes sense, and Dualism is incoherent.

This article originally appeared on my theology blog, Defense for the Hope, linked below in my Mini-Bio.