Understanding Atheism
Nov. 29, 2025
In the mid-2000's there were about 150 million atheists out of a word population of 6 billion according to World Christian Trends AD 30-AD 2200 p.4. Atheism is not a single monolithic belief. Rather different atheists have different beliefs, united only by one definite belief: that God does not exist. This differs from agnosticism which only claims to not know whether God exists or not. This also differs from the beliefs of Spinoza and Albert Einstein, that believe in God only as sort of an impersonal force pervading the universe. This article briefly outlines different kinds of atheism and some things a Christian can say to an atheist.
Early Practical Atheism
Practical atheism might accept that there is one or more gods, but denies that we should do anything with our lives based o that belief. For example, some people today claim to be Christians, but they live their lives no different than if they were atheists. So the key question is not whether they claim there is a god or not, but do they live as though it made any difference. Here are a list of Greek philosophies, and many of them taught practical atheism.
Epicureans thought that the gods might exist, but they don't care about anything as puny as us, so there is no point in caring about them. Many Epicureans believed the atoms from Democritus.
To some Stoics, God is a pantheistic, rational force called the logos.
Cynics believed that god's actions, if not just from random chance, are not necessarily good or trustworthy
Cyrenaics varied. Some thought no God at all, and others thought the world itself was a benevolent god.
Pythagoreans thought of one Supreme, incomprehensible god higher than lesser Greek gods, who used math to develop the universe.
Plato taught of a Supreme, transcendent, unchangeable good, righteous God, higher than the other gods, who was the prime mover and first cause. (This was not Zeus.)
Neoplatonists taught that the highest god is "the One", the ultimate good and the ultimate source of all being. Divinity descended from him to the World Soul and then other lesser, immortal beings.
The 30 or so pseudo-Christian gnostic groups had various views, but they seemed to come from Platonism and Neoplatonism.
Paganism and much of Hinduism (Upanishadic Hinduism excepted) are actually practical atheism. The "gods" did not eternally exist, and they are just spending time living in the universe sort of like we are. Upanishadic Hinduism believes in one pantheistic, impersonal god; they think that other Hindus' beliefs in other gods are just simplifications for more primitive minds.
Deism
Deism does not deny God, but is a form of practical atheism beginning with Nicolas of Orsemes (died 1382) that said God wound up the clock of the word at the beginning, and now is no longer involved. Everything, including human behavior runs like clockwork; there is no free will. It became popular in England from 1654-1679. They were for religious toleration, because many felt that all religions were basically the same.
Prominent deists included Herbert of Cherbury, Lord Shaftesbury, Gottfried Liebnitz, and Immanuel Kant. Some American deists were George Washington, Benjamin Franklin, Thomas Jefferson, and Thomas Paine. Franklin said he was not sure about the divinity of Jesus, but it did not really matter because he would find out after he died anyway. Jefferson was famous for having a copy of the Bible where he cut out with scissors the parts he did not like.
An example of deism in the church is the poem Desiderata; a poem found in the basement of a church in American in Revolutionary War times.
Renee Descartes (pronounced de-CART), (1596-1650) was a famous mathematician and philosopher whose most famous line is "I think, therefore I am". He has been called an atheist by some, and Blaise Pascal accused him of being a rationalist deist. Descartes was actually a Catholic, those his books were banned. Here is what he wrote: "By God, I understand, a substance which is infinite, independent, supremely intelligent, supremely powerful, and which created both myself and everything else […] that exists. All these attributes are such that, the more carefully I concentrate on them, the less possible it seems that they could have originated from me alone. So, from what has been said it must be concluded that God necessarily exists." So this puts him in the theist camp.
Bishop Fénelon (1675-1715) has a succinct critique of deism: "They [deists] credit themselves with acknowledging God as the creator whose wisdom is evident in his works; but according to them, God would be neither good nor wise if he had given man free will-that is the power to sin, to turn away from his final goal, to reverse the order and be forever lost." Lettres sur divers sujects, metaphysique et de religion Letter 5. Quoted from James Sire's The Universe Next Door p.52
Early Christians Against Atheism
The early church specifically saw atheism in their time as an opponent of Christianity. Pre-Nicene Christians wrote specifically against Atheism were Justin Martyr (c.138-165 A.D.), Theophilus of Antioch (168-181/188 A.D.), Origen (c.240 A.D.), Gregory Thaumaturgus (240-265 A.D.), and Lactantius (c.303-320/325 A.D.).
But besides believing God created the world, atheists had an alternate view of how everything was made: with atoms.
Leucippus, Democritus, and Atoms
Eleatics were an early school of Greek philosophy that said that everything was one, and a pantheistic god was in everything. Prior to all the previous Greek philosophers, Leucippus and his disciple Democritus opposed the Eleatics. They were the first philosophers who conjectured the existence of atoms, small, indivisible spheres that make up everything. Everything was some mixture of void and atoms, and there was on pantheistic god. So they did not believe the universe was created by any being, but rather by atoms interacting with the void. Technically they did believe in god-like beings, but they were mortal, made of atoms, and kind of like us, just greater.
Because of everything associated with their philosophy early Christians were strongly opposed to Democritus' atoms. Eleven Pre-Nicene writers starting with Justin Martyr (c.138-165 A.D.) unanimously wrote against atoms. The only exception is a twelfth, Minucius Felix (c.200 A.D). wrote about atoms in listing various philosophies but did not say if it was correct or wrong. The Ebionites, a heretical group, also wrote of the foolishness of the Greeks who though everything was made of atoms in Recognitions of Clement (c.211-231 A.D.) It "proved" that atoms were wrong, because if everything were made of atoms then everything would fall apart at once!
Moving forward in time, Christians started changing their view with Macrina (c.327-379 A.D.), the younger sister of bishop Basil of Cappadocia and bishop Gregory of Nyssa. She believed that atoms could exist, but that God made the atoms.
It's Turtles, All the Way Down!
A question to ask both true atheists and those who do not believe in an uncreated God is: when Zeus/ Gilgamesh, etc. created the universe, what did he stand on? One answer, given around 500 A.D. is that the world was supported by eight elephants. (It is truly a great power of observation that they knew it was eight and not another number!). Except that the Skanda Purana (7th-8th century A.D.) and Ramayana (7th-4th century B.C.) say only four elephants. But what do these elephants stand on? A big turtle. But what does the turtle stand on? – a bigger turtle. But what does … … it's turtles all the way down!
This is a problem with any religion that does not believe in an uncreated being. One modern religion that has this problem is Mormonism, as one Mormon admitted.
So unless the answer is "turtles" or similar, you have to believe there is something, or Someone, who is uncreated and existed in the eternal past. Christians, Jews, and others say it is a personal being called God. Those who have faith in "scientism" say it is an impersonal force, of scientific laws and random chance.
Four Philosophical Arguments for God
Non-evidential arguments (not really proofs) of God can be put into four categories: cosmological, ontological, teleological, and moral. A limitation of all these arguments is that they do not prove a Christian God, or even a personal God, just that Someone or something is eternally out there.
The Cosmological argument says that created thing have a cause, and a beginning. Going back to "turtles all the way down", then there has to be at least one thing that was uncaused and had no beginning. But there had to be something, or Someone, that was eternally existing. It is sort of like if someone is trying to jump out of a bottomless pit, tell them to push off the floor!
The cosmological argument has three forms:
Leibnitz – you can't get something from nothing
Thomist – you cannot get a finite being from an infinite regress of finite beings, any more than you can get an orange by adding an infinite number of apples to a basket.
Kalam – whatever began to exist has a cause, and the universe began to exist. William Lane Craig is a Christian who has written much on this.
Secular science teaches a point when everything began, including time, called the Big Bang. Some atheists say the cosmological argument is not valid if the universe has always existed. But unwittingly, their critique of the cosmological argument only validates it: an uncaused some thing (or someone) has always existed. Some atheists would rather believe in an infinite number of universes than an infinite deity. Again, unless it is "turtles all the way down" there is only one ultimate, eternal entity.
Time Magazine wrote an article about this in a review of the book God and the Astronomers by an agnostic astronomer named Robert Jastrow. He says that it's as if the astronomers have climbed and finally reached the top of the mountain of ultimate knowledge, and they found a band of theologians had been sitting there for centuries. In other words, there had to be some First Cause, such as God, from which everything was created.
The Ontological argument, championed by Anselm of Canterbury (1078) is my least favorite argument. It defines God as that by which no greater can be conceived. There are two problems with this. First, to what extent does God's existence depend on human intelligence and imagination. – not at all. Second, replace the word "great", however you have defined it, with "green", "tall" or some other adjective. What have you proved about anything?
A Christian speaker named David Prentiss gave a good talk on this argument though. He said that all atheists believed in a god. He defined god, generically as uncreated, immortal, all-powerful, and eternally existing. He said that the name of the atheists' god is "random chance".
The Teleological argument is not a proof but an observation. The intricacy of the universe, and the exact balance of physical forces require a designer. Looking at everything required for there to be life, and even animals and plants, and even intelligent life, the probability of this happening by random chance is astronomically small, even on a time scale of 3.5 billion years. Without going into scientific arguments here, this is what four famous scientists have said.
William Paley, a Deist, has a famous quote: "every watch requires a watchmaker." Or to put it in more modern terms, compare Mount Rainier and Mount Rushmore. Mount Ranier looks like it was formed by natural processes. But do the faces on Mount Rushmore looked like they were formed by natural causes? – of course not.
Isaac Newton (1642-1727) once made a working mechanical model of the solar system. An atheist friend marveled at it, and asked Newton who made it. Newton replied tongue-in-check, "Why it just made itself." His friend asked Isaac to stop joking and tell him who made it. Newton repeated what he said. His friend started getting angry. Newton finally said that if you cannot believe this simple mechanical model of the heavens was made without a maker, how can you believe the actual heavens were made without one?
Jacques Monod said, "Life appears on earth: what before the event, were the chances that this would occur? The present structure of the biosphere certainly does not exclude the possibility that… it's a priori probability was virtually zero." Chance and Necessity. 1972 p.136.
Nobel Prize winner Sir Francis Crick said, "An honest man armed with all the knowledge available to us now, could only state that in some sense, the origin of life appears at the moment to be almost a miracle, so many are the conditions which would have had to have been satisfied to get it going." Life Itself. 1981 Simon and Schuster p.88.
Nobel Prize winner Ilya Prigogine is famous for his work on equilibrium and non-equilibrium systems. He said, "The idea of spontaneous genesis of life in its present form is therefore highly improbably even on the scale of the billions of years during which prebiotic evolution occurred." (Prigogine et al. Physics Today Nov. 1972 pp.23-31.)
Theism is the Basis for Morality
If there is no ultimate God, there is no ultimate meaning or purpose in life either. We have no more meaning than "dust in the wind" .
Without a belief in God, there is no basic for morality. That does not mean that atheists cannot do moral things, and refrain from evil things, but rather they have no basis for doing so. Let's say you kill a mosquito in your house. Is that any better than killing a person? – Let's say someone murders a person in cold blood; it that any worse than killing a mosquito in your house? – why? Because they person did not want to be killed? – neither did the mosquito. Is there any value of life of a human being, more than a mosquito? Many atheists, especially some communists, would say none whatsoever. Other atheists would say that human life is more valuable, but they really can't say why.
When you finish a lab experiment, and you throw the chemicals in a test tube down the drain, is that any worse than throwing the chemicals of a human body down the drain, - if we are nothing more than just chemicals? Why? Apart from a divine being creating people with a certain dignity (in the image of God in Biblical terms) what dignity do we have?
Types of Atheism
Besides practical atheists, there are many types of atheism, and they overlap.
Philosophical - non-scientific atheism
Psychological - psychology explains all religion
Scientism - science will have every answer
Secular Humanism - humanity is the highest good
Objectivism – totally selfish but don't hurt others
New Atheists - aggressive against Christianity
Communists - people exist for the state
Postmodernism – Truth is only relative
Philosophical Atheism
Some famous western atheists were Frederich Nietzsche (1844-1900), David Hume (1711-1776), John Paul Sartre (1905-1980), and Voltaire (1694-1778).
David Hume wrote: "If we take in our hand any volume; of divinity or school metaphysics, for instance; let us ask, Does it contain any abstract reasoning concerning quantity or number? No. Does it contain any experimental reasoning concerning matter of fact and existence? No. Commit it then to the flames: for it can contain nothing but sophistry and illusion." (Enquiry concerning Human Understanding section 1 pt. 1)
Other famous atheists include Susan B. Anthony, Luther Burbank, Andrew Carnegie, Marie Curie , Thomas Edison, H. L. Mencken, Bertrand Russell, and Margaret Sanger.
Sigmund Freud: Psychological Atheism
Sigmund Freud(1856-1939) was an atheist who though religion was a "collective neurosis", though he still considered himself a Jew. While he explained everything through the ego (will), super-ego (roughly conscience), and id (natural impulses, and Oedipus complexes (where a child has sexual feeling for the opposite sex parent and is against the same sex one), other psychologists including his students Adler and Jung strongly disagreed with his emphasis.
B.F. Skinner (1904-1990) founded behaviorism, a school of psychology that viewed people as predetermined robots without free-will.
Charles Darwin and Scientism
Scientism goes beyond a belief in science or even trust in science. It turns science into an infallible idol, almost worthy of worship. Charles Darwin was a regular church goer as a young man, but over time he became an agnostic. Another example of scientism is Carl Sagan, an agnostic.
Once a physics professor of mine said that everything was either matter or energy, and if you could not measure or do an experiment to show something was true then not to believe it. We were asked to comment on that in our homework. (Importantly, I was just auditing the class.) I said that a person who believed that would not make a good spouse, because you cannot see or measure love. (I did not know at the time that he was divorced.) Anyway, I got a very long note back from the grader. I was glad that I was only auditing!
One often-overlooked argument for macro-evolution is that if there is no God, then there is no other rational alternative besides evolution. So many believe in evolution not because of the evidence, but because they have to as Richard Leewantin acknowledges this "prior commitment".
However, Biochemist Klaus Stosa said, "More than 30 years of research into the origin of life a better perception of the immensity of the problem of the origin of life on earth rather than to its solution. At present all discussion on principle theories and principles lead either end in stalemate or in a confession of ignorance." Quoted from I Don't Have Enough Faith to be an Atheist (Geisler, Frank Turek tape 31 one minute in.
On the other hand some Christians, such as Cliffe Knectle, C.S. Lewis, and former atheist Alister McGrath believe in theistic evolution. In other words, God created using macro-evolution. This is not atheism. McGrath wrote a critique of Richard Dawkins' book The God Delusion called The Dawkins Delusion?.
John Dewey and Secular Humanism
Not all atheism is selfish. John Dewey (1859-1952), professor at Columbia and famous for the library's Dewey-decimal system, was involved with the 1933 Humanist Manifesto. He believed there was no God, but humans had responsibility for themselves, and their betterment was up to them. John Dewey was one of the most influential American in the first half of the 20th century; he had a key role into transforming schools from Christian places into liberal secular ones.
John Dewey actually rejected being called an atheist, but you can judge for yourself with his quote: "…there are forces in nature and society that generate and support the ideals …. It is this active relation between ideal and actual to which I would give the name ‘God.'" (A Common Faith p.51) quoted in the Wycliffe Dictionary of Theology p.71.
The science and science fiction writer Isaac Asimov was a signer of the Humanist Manifesto II (1973). Humanists are not as much anti-Christian as anti-God.
Ayn Rand and Objectivism
Not all atheists are communists or liberals. Ayn Rand, a Russian-born, Soviet-educated lady who started objectivism, was staunchly anti-communist and helped a Republican candidate. Her philosophy has been described as "ethical egotism", or basically don't hurt others, but do whatever is best for yourself, not others.
Years ago at the university I attended there was an Ayn Rand society booktable next to our Christian booktable. A Christian friend of mine, Phil, working at the book table, was talking with a few of the Ayn Rand people. He ask them, if it would be better for you if other people selflessly helped others, and you did not, then wouldn't it be more benefit for you not to tell others about objectivism, so that they could help you and others without you helping them? After a couple of days, the Ayn Rand booktable was gone.
Madalyn Murray O'Hair and New Atheism
Starting in 1925, the American Association for the Advancement of Atheism, later succeeded by the League of Militant Atheists, had as its goal to attack all religions through atheistic literature. This has been called New Atheism, which is basically atheism with an anti-Christian chip on its shoulder.
Atheists such as Nobel-Laureate physicist Steven Weinberg believed that science and religion are incompatible, and scientists should do all they can to weaken religion. New atheists include Madalyn Murray O'Hair (1919-1995), Richard Dawkins, and Cristopher Hitchins (a self-proclaimed antitheist).
If you think of all the religious wars throughout history, it sees those as a great evil caused by belief in one or more gods. Whether Hindus fighting Hindus for religious reasons, Muslims killing Jews, Hindus, Christians, and atheists, or Christians like Charlemagne massacring Saxon pagans, Catholics and Protestants fighting, it all is evil. You can certainly understand their point.
Karl Marx and Communism
However, while religious massacres were bad, atheists massacring others have been even worse. Besides the atheistic French Revolution, it was communist atheists that massacred people in the Chinese Cultural Revolution, Pol Pot in Cambodia, North Korea, and the Ukrainian famine. These were not done to convert people to atheism per se, but rather because of the atheistic view that human life has no intrinsic value. Truth is not objective, but whatever helps communism.
Communism has been the official "non-religion" of over a fifth of the world. You had to be an atheist to join the Chinese Communist Party. Atheism was the official philosophy or the Soviet Union (though not Russia), as well the Khmer Republic, North Korea, Laos, and other countries.
Post-Modernism
While most -atheists believe it is true there is no God, post-modernism denies there even is absolute truth. It is a cynicism that we can ever know the truth, or that we should care. Something might be true for me, but not for you, and vice versa. Post-Modernists might say there is no truth, or we cannot know what is true, there are no absolutes, or there is no morality. Whether something is true is unimportant; rather, is it useful? How do we know that history, morals, or science are true? Why should we care? If something makes us happy, now or later, why should we care about anything else?
How do you know for certain?
(I am going on memory here, so some of this might be imprecise.) Once after the evangelist D.L. Moody finished preaching a sermon a man came up to him and said, "Sir, I am an atheist." Then Moody asked him, out of all the knowledge that mankind has, what percentage do you think you know? The man gave an answer as a small number. Then Moody asked out of all the information in the universe, what percentage do you think mankind knows. Again, another small number. Then Moody said that in all of that knowledge that people know and you don't, and in all of the information that people don't know is there any chance that there might be a God you have not encountered yet? The man said there was. Moody said, then you are not an atheist, you are an agnostic. Moody then asked him, if there were a God out there, and He loved you and wanted the best for you, would you want to know about Him? The man said sure. Moody said, then you are not an agnostic, you are a seeker. Then Moody said if there was a book that allegedly came from this God, would you want to read it? The man said he would. So Moody gave him a copy of the New Testament.
Here is a similar discussion Norm Geisler had.
Non-believer: I don't believe in God; I am an atheist.
Geisler: Are you absolutely sure there is no God.
Non-believer: Well no, I am not absolutely sure. I guess it's possible there might be a God.
Geisler: So you're not really an atheist then, you're an agnostic then.
Non-believer: So I guess I am an agnostic then.
Geisler: What kind of agnostic are you? …
Non-believer: What do you mean?
Geisler: Well, there are two kinds of agnostics; there's the ordinary agnostic that say she doesn't know anything for sure, and then there's the ornery agnostic that says you can't know anything for sure.
Non-believer: I'm the ornery kind, you can't know anything for sure.
Geisler: If you say you can't know anything for sure, then how do you know that for sure?
Non-believer: What do you mean?
Geisler: How do you know for sure that you can't know anything for sure? You can't be a skeptic about everything, because that would mean you have to doubt skepticism.
Non-believer: OK, I guess I can know something for sure. I guess I am an ordinary agnostic.
Geisler: Since you admit now that you can know, why don't you know that God exists?
Non-believer: Because nobody has showed me any evidence.
Geiser: Would you be willing to look at some evidence?
Then Geiser gave the unbeliever a book by Frank Morrison, called Who Moved the Stone?
They visiting him later. Several weeks later he became a Christian.
From Why I don't Have Enough Faith to be an Atheist. reading 10 Time: 1:35 to 5:04.
You have to be politely persistent.
A Deist Response
Immanuel Kant (a deist not an atheist) wrestled with this and came up with a definition of good independent of God. He discussed "the science of right" and defined good as what was done out of a sense of duty. (sounds sort of stoic). When I was an undergrad in college, a friend had to write a paper on Kant, and I was interested in reading it before he turned it in. He went to lunch and told me to toss the paper on his bed when I was done. So I did so and I joined him for lunch. He asked me what I thought of Kant's view, and I told him I didn't agree with Kant at all. At the Nuremberg trials the soldiers who executed Jews in the Holocaust had the defense "I was only following orders". Was what they were doing good, because they did it out of a sense of duty? So I told him I felt it was my sense of duty to tear up his paper and throw it away? Then I asked him, "wasn't that good?" Then he (jokingly) picked up a knife and talked about his sense of duty. I guess so much for defining good as what is done out of a sense of duty!
This is Urgent!
Some agnostics and atheists don't see any urgency to settle the issue; there are lots of facts, such as Stiff ODE's and matroids, that if you don't understand them or even misunderstand them, that is not going to affect anything (unless you are doing heavy mathematics). But this is different. There are scriptures, reported to be from God, that says your ultimate destination in eternity depends on what you decide and commit to now before you die.
I had a friend in college, who was a scoffer of Christianity. I gave him the book by Josh McDowell, Evidence that Demands a Verdict, which he read cover to cover. After that he "believed', but he did not become a believer, in that he still had some sins he was unwilling to part with. But he would talk with atheists anyway and show them they were wrong. What he told one of them, which I thought was a very good point, is "you may have a good offense, but you have no defense." That seems true for most atheists. You might ask them what they believe, and what they think. And then see how that stacks up against the cosmological, teleological, and moral arguments.
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By Steven M. Morrison, Ph.D.