Is There a God?

Is there a God? Christians don't believe on blind faith. Scripture says God has made himself known through what he has made (Romans 1:20) and the moral law written on our hearts (Romans 2:15). This section lays out the classic arguments for God's existence, as formulated by philosopher William Lane Craig and others, along with examples from the natural world that point to design.

We can't make God appear in front of you, and no argument can force him to show himself. But he has not hidden. He has revealed himself in what he has made, in the moral law written on our hearts, in Scripture, and above all in Jesus, who rose from the dead. These arguments don't replace faith; they clear the way for it. Our part is to respond: to call out to him in faith. "Anyone who comes to him must believe that he exists and that he rewards those who earnestly seek him" (Hebrews 11:6).

The Cosmological Argument (Kalam)

The universe began to exist, so it has a cause beyond itself.

Everything that begins to exist has a cause.
The universe began to exist.
Therefore, the universe has a cause.

This is one of the most discussed arguments in modern philosophy of religion. The logic is valid: if both premises are true, the conclusion follows. So the question is whether the premises are more plausible than their denials.

If the universe has a cause, what must that cause be like? It created all space, time, matter, and energy, so it must itself be spaceless, timeless, immaterial, and enormously powerful. And it must be personal: an impersonal, timeless cause would either always produce its effect or never produce it. Only a free agent can choose to create a universe with a beginning. That is a remarkable description of God.

Premise 1: Things don't pop into being from nothing

Out of nothing, nothing comes. If things could come into existence uncaused from nothing, we would expect to see it happen all the time, and it would be inexplicable why only universes, and not bicycles or horses, do so. Every experience we have confirms premise 1.

Premise 2: Philosophical evidence

An actually infinite number of past events leads to absurdities. If the past were infinite, an infinite series of days would have had to be completed one by one to arrive at today, and an infinite series cannot be completed by successive addition. So the past must be finite.

Premise 2: Scientific evidence

The standard Big Bang model describes a universe that began to expand from an initial state a finite time ago. In 2003, physicists Arvind Borde, Alan Guth, and Alexander Vilenkin showed that any universe that has, on average, been expanding throughout its history cannot be infinite in the past; it must have a past boundary. The second law of thermodynamics points the same way: if the universe were infinitely old, it would already have run down.

“Then who caused God?”

Premise 1 says everything that begins to exist has a cause. God, by definition, never began to exist. Any explanation of reality must end in something uncaused; the evidence shows that it cannot be the universe, which had a beginning.

“Quantum physics shows things can come from nothing.”

Quantum events arise from the quantum vacuum, which is not nothing. It is a sea of energy governed by physical laws. Nothing means no space, no energy, no laws, nothing at all.

“Maybe the cause was impersonal, like a law of nature.”

Laws of nature describe what happens within the universe; they don't cause anything on their own, and they didn't exist before the universe. A timeless, unchanging cause producing an effect with a beginning points to a free choice.

Sources: William Lane Craig, Reasonable Faith (3rd ed., 2008), chapter 3; William Lane Craig, On Guard (2010), chapter 4; A. Borde, A. Guth, A. Vilenkin, "Inflationary spacetimes are incomplete in past directions," Physical Review Letters 90 (2003)

The Argument from Contingency

Why is there something rather than nothing?

Everything that exists has an explanation of its existence, either in the necessity of its own nature or in an external cause.
If the universe has an explanation of its existence, that explanation is God.
The universe exists.
Therefore, the universe has an explanation of its existence, and that explanation is God.

Some things exist necessarily: they could not fail to exist. Everything else is contingent: it happens to exist but might not have, so it depends on something else. You, the earth, stars, and galaxies are all contingent.

The universe is simply the collection of contingent things, so it too needs an explanation outside itself. That explanation must be a necessary, uncaused being beyond space and time, which is what Christians mean by God. Unlike the Kalam argument, this one works whether or not the universe had a beginning.

Premise 1 is common sense

If you found a translucent ball in the woods, you would assume it had an explanation. Making the ball the size of the universe doesn't remove the need for one.

Premise 2 follows from the nature of the universe

The universe is all of space, time, and matter. Its explanation must therefore be beyond space and time, immaterial, and uncaused: a necessary being. That fits the description of God.

“The universe just exists. It's a brute fact.”

That's not an explanation; it's a refusal to ask the question. We never accept "it just exists" for anything else in the universe. Why make an exception for the whole?

“Maybe the universe exists necessarily.”

Nothing about the universe appears necessary. Its particles, laws, and constants could have been different, and the universe as a whole could have failed to exist.

Sources: G. W. Leibniz, The Principles of Nature and Grace (1714); William Lane Craig, On Guard (2010), chapter 3

The Fine-Tuning Argument

The laws of physics are set within a razor's edge to allow life.

The fine-tuning of the universe is due to physical necessity, chance, or design.
It is not due to physical necessity or chance.
Therefore, it is due to design.

Physicists have discovered that the constants and quantities in the laws of nature fall within extraordinarily narrow ranges that allow life. If they were even slightly different, there would be no stars, no planets, no chemistry, and no life. This is recognized across worldviews; the debate is over how to explain it.

The cosmological constant

The energy of empty space, which drives the expansion of the universe, is often described as fine-tuned to around one part in 10^120. Much larger, and the universe would have flown apart before galaxies could form; much smaller (negative), and it would have recollapsed.

The initial order of the universe

Mathematician Roger Penrose calculated that the odds of the universe's low-entropy starting state arising by chance are about one in 10^(10^123), a number so large it could not be written out even with one digit on every particle in the universe.

Not physical necessity

Nothing in physics requires the constants to have the values they do. Physicists treat them as independent inputs, and many theories allow vast numbers of alternatives.

Not chance

The odds are so small that chance is not a reasonable explanation. Even the atheist astronomer Fred Hoyle, studying how stars produce carbon, concluded that "a superintellect has monkeyed with physics."

“If the universe weren't fine-tuned, we wouldn't be here to notice.”

True, but it doesn't remove the need for an explanation. Philosopher John Leslie's illustration: if you survived a firing squad of 100 trained marksmen, you shouldn't shrug and say, "Of course they all missed, or I wouldn't be here." You should ask why they missed.

“There could be infinitely many universes (a multiverse).”

There is no direct evidence for other universes. Any mechanism that generates universes would itself need to be fine-tuned. And a multiverse predicts that we should most likely be isolated brains popping into existence, not observers in a large, orderly universe like ours.

Sources: William Lane Craig, Reasonable Faith (3rd ed., 2008), chapter 4; Roger Penrose, The Road to Reality (2004); Fred Hoyle, "The Universe: Past and Present Reflections," Engineering and Science (November 1981); John Leslie, Universes (1989)

The Moral Argument

Real good and evil require a real moral lawgiver.

If God does not exist, objective moral values and duties do not exist.
Objective moral values and duties do exist.
Therefore, God exists.

Objective means true whether or not anyone believes it. Most people recognize that some things, like torturing a child for fun, are really wrong, not just unpopular or unhelpful.

Without God, morality reduces to evolution, culture, or personal preference. None of those can make anything truly right or wrong; they only describe what people happen to feel. God's own good nature provides the standard, and his commands give us our duties.

This argument also answers the problem of evil. If we agree that evil truly exists, we have already agreed that good exists, and that there is a moral law telling them apart. As Wes Huff puts it, "a moral law needs a moral lawgiver."

Premise 1

Many atheist thinkers agree. If humans are only the product of blind natural processes, morality is a useful survival instinct, and there is no ultimate fact of the matter about right and wrong.

Premise 2

We perceive moral truths as clearly as we perceive the physical world. Someone who sincerely thinks there was nothing really wrong with the Holocaust is not offering a different opinion; they are missing something real.

“You can be good without believing in God.”

Absolutely. The argument isn't that atheists can't be moral, but that without God there would be no objective standard of good to live by. See "You don't need God to be a good person."

“Is something good because God commands it, or does he command it because it's good?”

Neither. God's commands flow from his own perfectly good nature. Goodness isn't arbitrary, and it isn't a standard outside God; it is grounded in who God is.

“Morality evolved to help us survive.”

Evolution might explain why we have moral feelings, but not whether those feelings track anything real. If morality is just survival instinct, then "cruelty is wrong" is no more true than "I prefer chocolate."

Sources: William Lane Craig, On Guard (2010), chapter 6; C. S. Lewis, Mere Christianity, Book 1; Wes Huff, interview on The Shawn Ryan Show (episode 279)

The Resurrection of Jesus

If Jesus rose from the dead, God exists, and we know who he is.

There are well-established historical facts about Jesus' death and its aftermath: his burial, the empty tomb, the appearances, and the origin of the disciples' belief.
The best explanation of these facts is that God raised Jesus from the dead.
Therefore, God exists, and Jesus is who he claimed to be.

The other arguments point to a Creator. The resurrection identifies him. If God raised Jesus from the dead, he vindicated Jesus' claims to be the Son of God. The Evidence Explorer covers this in detail.

Sources: William Lane Craig, Reasonable Faith (3rd ed., 2008), chapter 8

Signs of design

Our Moon

The Moon is unusually large compared with its planet, and it does far more than light the night.

It stabilizes the tilt of Earth's axis. Without it, Earth's tilt could swing wildly over long periods, causing extreme climate changes (Laskar and colleagues, Nature, 1993).
Its tides mix the oceans and coastal waters, supporting rich marine life.
The Sun is about 400 times wider than the Moon and about 400 times farther away, so the Moon covers the Sun almost exactly during a total solar eclipse. Those eclipses have allowed important scientific discoveries, including a key early test of Einstein's general relativity in 1919.

Good to know: The Moon is slowly moving away (about 3.8 cm per year), so perfect eclipses are a feature of our era in Earth's long history. Some see that as remarkable timing for a world with observers.

A planet made for life

Earth combines many conditions life needs, all at once.

It orbits in the zone where liquid water can exist, in a nearly circular orbit that keeps temperatures stable.
Its magnetic field shields the atmosphere and surface from the solar wind and cosmic radiation.
Its ozone layer blocks most harmful ultraviolet light, yet lets through the light life needs.
Plate tectonics recycle carbon and nutrients and help regulate climate over long periods.
Its atmosphere is transparent, allowing us to see and study the universe.

Good to know: Astronomers are still learning how common Earth-like planets are. The argument is strongest when focused on how many conditions must align together.

Water

Ordinary water has extraordinary properties that make life possible.

Unlike most substances, water expands as it freezes, so ice floats. Lakes freeze from the top down, insulating the life below instead of freezing solid.
It can absorb a lot of heat with little temperature change, stabilizing oceans, climate, and body temperature.
It dissolves more substances than almost any other liquid, carrying nutrients through soil, oceans, and living cells.

The carbon "coincidence"

The element of life exists because of a precisely placed energy level inside the atom.

Carbon is made inside stars when three helium nuclei combine. Fred Hoyle realized this would almost never happen unless carbon had an energy level at a very specific value, and predicted it before it was found.
Experiments confirmed the energy level, now called the Hoyle state.
Hoyle, then an atheist, wrote that "a common sense interpretation of the facts suggests that a superintellect has monkeyed with physics, as well as with chemistry and biology."

Information in the cell

Every living cell runs on coded information.

DNA stores instructions in a four-letter chemical code, read and translated by molecular machines into proteins.
The human genome is about 3 billion letters long, and nearly every cell in your body carries a copy.
In our experience, coded information always comes from a mind. How the first self-replicating, information-rich system arose remains one of science's great unsolved questions.

Good to know: This is an argument about the origin of life, not about later biological change.

Partners that need each other

Some living things depend completely on one another.

Fig trees and fig wasps: many fig species can only be pollinated by their own specific wasp, and the wasp can only reproduce inside that fig's flowers. Neither survives without the other.
Yucca plants and yucca moths: the female moth gathers pollen, deliberately packs it onto the yucca's flower, and lays her eggs there. Her larvae eat some of the seeds, but leave plenty to grow.
Clownfish and sea anemones: a protective layer of mucus lets the clownfish live among the anemone's stinging tentacles, which protect it from predators, while the clownfish defends and cleans the anemone.

Good to know: Biologists explain these partnerships through coevolution. The design argument asks whether intricate interdependence like this is best explained by unguided processes alone.

The woodpecker

A bird that hammers wood with its head, thousands of times a day.

Woodpeckers can strike up to about 20 times per second, with their heads decelerating at forces over 1,000 times gravity.
Their tongues are remarkably long. In many species, the tongue's supporting bones (the hyoid) wrap around the back of the skull, sometimes reaching the forehead or nostril.
A 2022 study found their heads don't work as shock absorbers, as was long believed. Instead, the beak and skull act like a stiff hammer, and the bird's small brain, tightly packed in the skull, can tolerate the impacts.

Good to know: Older claims about built-in "shock absorbers" are out of date. The newer findings still show a design suited for an extreme way of life.