Recently there seems to have been a rash of debates between atheists and Christian apologists. Of course, we had the much-ballyhooed debate between Ken Ham and Bill Nye on creationism versus evolution ("Ham on Nye"), which only served the purpose of giving Ham's ridiculous beliefs attention they did not deserve. And, it got Ham enough money from donors an taxpayers to complete his theme park.

However, most debates involve an atheist scientist, philosopher, or former clergyperson against a Christian theologian or clergyperson. Occasionally we have an atheist layperson against a clergyperson. It is very unwise for a layperson to debate a theologian.

In the latest debates I have watched, as well as many others I have witnessed over the years, including several of my own, the Christians are almost always very smooth and well prepared. The reason is not that their arguments are so persuasive but that they generally have spent years in front of religion classes, lecture audiences, and church congregants, polishing the same old arguments.

And, after you have watched or participated in a number of these events, you find there very seldom is a new argument. All have all been refuted many times, but most in the audiences do not know that.

Atheists, on the other hand, with one or two exceptions, do not make a living promoting atheism and so have a much tougher job preparing for these debates.

Certainly atheist debaters will make their own arguments for atheism during their opening statements. I advise, again from observation and experience, that they limit these to their particular areas of expertise and avoid subjects outside those areas.

During their opening statements and throughout the debate, apologists are likely to make arguments with which atheists may not be so well versed. So, when the time comes for rebuttals, atheists often cannot provide cogent responses, or any responses at all, and so lose debating points.

An experienced debater will make note of every point his or her opponent makes and try to provide at least a one sentence response. That will prevent the opponent from coming back and saying, "My atheist friend never replied to this point." This takes experience. I never had enough to be good at it. In a debate, impressions are more important than the substance of an argument and not answering a point makes a bad impression.

In what follows I will provide a primer on the most common arguments made by apologists and suggest canned responses. By memorizing or bringing notes containing these responses to the debate, the atheist can be just as smooth as the preacher.

I do not provide any technical details. These suggestions are meant to be short, punchy statements to use during your rebuttals, which are usually time-limited. If you are a cosmologist, biologist, or biblical scholar, you don't need me telling you what to say on those subjects. If you are a non-expert on any subject, you should not say anything about it beyond your competence. Your opponent may call you out on it. I have seen that happen.

Note that there are a lot of arguments that could come up. Not all will be used in your debate because of time, so you need to study your opponent to learn his favorites. But you also need to come prepared with all of these responses to avoid as many surprises as possible.

Dan Barker, who is probably the most experienced atheist debater, with over a hundred under his belt, offers this advice:

"Debating is tough. As you say, there are so many ways the ball can bounce. But you are right that we should try to touch on every point raised, at least minimally. But I learned a long time ago that it is impossible to say it all in one evening event. (Written debates are different.) So don't try to 'squeeze it all in' or it can look frantic, rushed. Concentrate on our best knowledge. As long as we are prepared with some kind of adequate response to every possibility, as you say, then we can lead with our strength and do our best to impress the audience. Few people will walk away remembering even 10% of what was said, so impressions are important. Humor helps. A relaxed attitude helps. Confidence helps. Kindness and charity toward our opponents, some well-turned phrases and pithy one-liners, an attitude of honesty help. Sometimes an audience member will walk away with nothing more than an impression, a leaning toward or away from one of the debaters, which will influence their future learning. . . . in addition to the facts."

I will mainly emphasize scientific arguments, that is, those based on empirical evidence or lack thereof. However the atheist debater is very likely to be confronted with any one of many possible philosophical arguments based on logic alone, so I will present these first.

God can be proved to exist by logic alone. For example, we have the ontological argument, which appears in many forms. It was first proposed by St. Anselm in the 11th century. He defines God as "a being than which no greater can be conceived." If such a being only exists in the mind, then we could conceive of a greater being. But we cannot imagine a greater being than God, so God must exist in reality.

You are right; this argument has been proposed in many forms over the centuries. All have logical flaws. As for the original Anselm argument, it can be used to prove the existence of many nonexistent things such as the perfect pizza.

But there is a basic point to be made here. Ontological arguments are defined as those made from logic alone with no reference to observation. But no logical deduction can tell you anything that is not already embedded in its premises. All logic does is draw the conclusions that follow from those premises and check for any inconsistencies. Only by observation can we demonstrate whether the premises accurately describe or reflect the real world.

Science and religion are compatible as evidenced by the fact that many scientists are believers.

They are actually a relatively small minority. Only 7 percent of the members of the National Academy of Sciences, the elite of American science, believe in a personal God. Believing scientists compartmentalize their brains, leaving their critical thinking skills at the lab when they go to church and leaving their Bibles at home when they go the lab. God is not a coherent part of the scientific model of any believing scientist.

Science and religion are fundamentally incompatible because of their contradictory views on the source of knowledge. Science assumes that only by observation can we learn about the world. Religion assumes that, in addition, we learn by revelations from God.

Science was the result of Christianity, which introduced the use of rational thinking. Galileo, Newton, and other early scientists were Christians.

Science was well on its way in ancient Greece and Rome. But the Catholic Church muffled science when it took over the Roman Empire in the 4th century, ushering in the 1,000-year period known as the Dark Ages. This ended with the Renaissance and the rise of the new science, when people could once again think and speak more freely. So it is ludicrous to argue that science was a product of Christianity.

While it is true that great Christian theologians, notably Augustine and Aquinas, applied rational thinking to their theology, they viewed science as a means to learn about God's creation. They always insisted that revelation rules over observation. Galileo was the first true scientist of the modern age when he insisted that observation rule over revelation. That got him into trouble.

Of course Galileo and Newton were Christians. Their only other choice was to be burned at the stake. Atheism did not appear openly until the French Enlightenment a century later. That light was produced by the mind, not the flames engulfing a heretic.

The obvious presence of design and complexity in the world, especially in life, proves there was a designer.

That was a good argument prior to Darwin when people had no idea how life came about. Darwin showed that complex organisms evolve from simpler ones by purely natural processes, without the need for a more complex designer. It is important to note that Darwinian evolution implied many predictions that could have been falsified but were not. For example, evolution requires that the sun and Earth are much older than seemed possible at the time from physics. It was not until the twentieth century, with the discovery of nuclear fusion as the source of energy for the sun, that this problem was solved.

In physics as well as biology, simplicity begets complexity. A beautiful snowflake comes from unstructured water vapor. The notion that intelligent design is necessary for the complexity of the universe is completely wrong.

Many Christians believe in evolution.

Not really. Surveys indicate that what most believe in is God-guided evolution. That is not evolution as understood by science. That is intelligent design. There is no room for God in evolution.

Science still has not shown how life began.

That is true; but it does not follow that life had to be created by God. To assert that, you have the burden of proving that science will never discover the natural origin of life. We have no reason to think that's impossible. The basic ingredients of life are copious in space. Amino acids were produced spontaneously out of simple ingredients in the lab in 1953 by graduate student Stanley Miller after running his experiment for only a week.

The big bang proved the universe had a beginning. Everything that begins has a cause. Therefore the universe had a cause, which was God (Kalām cosmological argument).

Modern cosmology implies that our universe began in total chaos and so possesses no memory of a creation or creator. A number of models, fully worked out mathematically, show that no laws of physics were necessarily broken to produce the universe. Quantum mechanics demonstrates that not everything that begins has a cause.

The universe began with a singularity that marked the beginning of time.

A singularity is an infinitesimal point in space with infinite energy density. Quantum mechanics shows that such singularities do not occur in nature. I am surprised this argument continues to be made by apologists. One of its creators, Stephen Hawking, abandoned it almost 30 years ago. See his book A Brief History of Time, which came out in 1988.

Modern cosmology now has strong reason to think that our universe is just one of an endless number of universes called the "multiverse." The multiverse is infinite and eternal; it had no beginning and will have no end. There was no need for a creator because there was no creation.

We cannot detect universes beyond our own. Therefore they are not science.

Science deals all the time with objects, such as quarks and black holes, that have not been directly detected. Since multiple universes are strongly suggested by modern cosmology, they must be considered when we debate theological questions. As long as they are not ruled out, they cannot be used as a god-of-the-gaps argument for the necessity of a creator. What's more, other universes are in principle detectable by their effects on the cosmic microwave background.

Where did the mass and energy of the universe come from?

The total mass-energy of the universe is zero with the positive energy of matter exactly balanced by the negative energy of gravity. This proves it could have come from a prior state of zero energy without violating any laws of physics. In one published scenario, our universe came from an earlier universe by quantum tunneling.

How can something come from nothing?

"Nothing" is notoriously difficult to define. To define it you have to give it some property. But then if it has a property it is not "nothing." So this is an incoherent question unless you define nothing as an empty vacuum. In any case, the multiverse didn't have to come from anything. It always was.

Atheists claim that the universe just "popped" into existence. I can't believe this. It's preposterous.

Just because you can't believe it, doesn't mean it could not have happened. A number of plausible scenarios for the natural origin of the universe have been published by reputable cosmologists in reputable scientific journals. If you insist they are impossible, then you have the burden of disproving them.

Also, are you implying it is preposterous to believe that the universe popped into existence from nothing by an act of God? Now, that is preposterous.

[Note: If you want more details on debating cosmology, see the debate between cosmologist Sean Carroll and apologist William Lane Craig at the Greer-Heard symposium in New Orleans, February 21, 2014.]

Where did the laws of physics come from?

What we call the "laws" of physics are not something inherent in the universe. They are not commandments that material objects must obey. They are principles that physicists build into models to describe their observations. We should not assume that any of the ingredients in the models of physics correspond one-to-one with actual objects of ultimate reality. Of course, they must have something to do with reality to agree with observations. But we have no way of knowing exactly what that something is, so we waste our time arguing about it.

If the constants of physics were just slightly different, life would have been impossible. The probability that this happened by accident is infinitesimally small. Therefore they had to be fine-tuned by God.

While our kind of life would not have evolved had the constants been different, a number of independent computer simulations by competent scientists have demonstrated that some form of life in the universe would be possible over a wide range of constants. It is wrong to assume that Earth life is the only possible kind of life.

Furthermore, events with infinitesimally low probability happen every day. Given all the accidents that led to your ancestors, what is the probability you would have existed? To judge that one event is more likely than another you must compare their probabilities. What is the probability that there exists an all-powerful, all-knowing, absolutely good supreme being presiding over this vast universe that, at the same time, guides every leaf that falls to the ground, listens to every human thought, and lets a child die in agony from leukemia every four hours in the United States?

In fact, an all-powerful, all-knowing, absolutely good God is logically inconsistent with all the pain and suffering in the world. This is the best reason of all for nonbelief.

God gave humans free will so he cannot control suffering.

Perhaps he cannot control of the suffering caused by humans, but the natural disasters and diseases that kill thousands every year are not the result of human actions.

How can there be objective morality without God?

Socrates proposed what is called the Euthyphro dilemma: Either (a) God wills us to do what is good because certain acts are good, or (b) an act is good only because God wills it. If (a), then moral values are independent of God. If (b) then there is no morality because God can will whatever he wants. In this case, if he asks you to kill a baby, would you do it? If you answer, "That would be against God's nature," then you are adopting (a), admitting that there is an objective morality that does not depend on God. If that is the case, then atheists can be just as objectively moral as theists.

Don't atheists believe that morals are relative, depending on the situation?

Maybe some do. There is no dogma that all atheists are required to follow. But most atheists and theists hold to the same basic set of objective morals and ethics that evolved over the millennia from the need to live together in society. Many studies show that atheists are at least as moral, and perhaps even more moral, than Christians.

What about all the millions of people murdered by atheists: Hitler, Stalin, Mao, Pol Pot?

Hitler was not an atheist. The rest did not kill in the name of atheism while throughout history Christians, Muslims, Hindus, and others have killed millions in the name of their gods. Pope Innocent III alone was responsible for a million innocent deaths during the Fourth Crusade. Now, if there ever was a historical figure who was misnamed, it is Pope Innocent III.

There is convincing evidence that Jesus was a historical figure who performed miracles and rose from the dead.

There is absolutely no evidence that the Jesus of the gospels even existed. He is only mentioned in the New Testament, which was written long after his death by people who did not know him. St. Paul says little that suggests a historical Jesus. He also did not know Jesus. His "evidence" for Jesus is just his own mystical visions. He said, "I want you to know, brothers and sisters, that the gospel I preach is not of human origin. I did not receive it from any man, nor was I taught it; rather, I received it by revelation from Jesus Christ." (Galatians 1: 11-12).

The fact that Jesus is not mentioned by any of the many Roman historians of the time, some living in Jerusalem and who wrote voluminously, proves beyond a reasonable doubt that the Jesus described in the gospels is largely of not totally a fictional character. However, secular scholars disagree on whether Jesus is a historical figure. Bart Ehrman thinks he did exist, as an apocalyptic preacher. Robert Price think's he is not historical.

What about Josephus and Tacitus?

Both were born after Jesus's supposed crucifixion, so obviously they were not eyewitnesses and wrote long after the fact. Furthermore, the frequently quoted passage from Josephus: "Now there was about this time Jesus, a wise man, if it be lawful to call him a man," is now recognized to be a much later forgery. Tacitus and Josephus, at best, were writing about a new death cult called Christianity, which certainly existed by that time.

There is just as much evidence for the existence of Jesus as for Socrates.

Not true. No one who wrote about Jesus ever knew him as a real, living human being. Three people who wrote about Socrates at the time knew him: Plato, Aristophanes, and Xenophon.

Jesus was a great moral teacher whose teachings superseded those of the Old Testament and brought a new code of morality to humanity.

In Mathew 5:17-5:18 Jesus says, "Think not that I am come to destroy the law, or the prophets: I am not come to destroy, but to fulfill. For verily I say unto you, till heaven and earth pass, one jot or one tittle shall in no wise pass from the law, till all be fulfilled." But, then, the Bible is full of contradictions, so I am sure my opponent can find a passage where Jesus says the opposite.

Of course many of Jesus's teachings were moral. However, none was original. There are no significant moral teachings of Jesus, such as the Golden Rule, that did not appear hundreds of years earlier in many cultures.

More important, you can dig around and find many of Jesus's pronouncements that are immoral by modern, objective standards. In Matthew 10:34-35 he says, "Think not that I am come to send peace on earth: I came not to send peace but a sword. For I am come to set a man at variance against his father, and the daughter against her mother, and the daughter in law against her mother in law." And in 10:37: "He that loveth father or mother more than me is not worthy of me: and he that loveth son or daughter more than me is not worthy of me."

But what makes Jesus one of the most unpleasant characters in all of fiction, along with the Old Testament God Yahweh (quoting Richard Dawkins), is that he dooms everyone on Earth who does not worship him to an eternity in hell. The six million Jews who died in the holocaust just moved from one furnace to another.

Atheists believe the only reality is matter. Yet we have many examples of immaterial things such as thoughts, emotions, information, logic, and mathematics. How can that be reconciled with a purely material world?

Once again, there is no atheist dogma and we have some atheists who are not materialists.

While the items you mention are not material objects, they appear only in a material context. Thoughts and emotions are observable electrochemical signals in the brain. If there were no brains, there wouldn't be any thoughts or emotions. Information is stored in binary states within purely material computers. Logic and mathematics are exhibited by particles of graphite or ink on paper, or particles of chalk on a blackboard.

If there is no God, how can there be meaning and purpose in life?

When Darwin saw all the pain and suffering that exists among living things, he lost whatever faith he may have had in a beneficent God. As for human life, for most of history it was, as Thomas Hobbes said, "nasty, brutish and short." However, this has changed--at least for those of us who are fortunate to live in the developed world. Thanks to science--and no thanks to religion--we are free from much pain and suffering.

As former preacher Dan Barker says, there is no "purpose-driven life," but there is "life-driven purpose." We have time and the means to pursue other goals beyond mere survival, and have the opportunity to live very happy, meaningful lives. The almost-certain fact that there is no life after death gives us all the more reason to live life in the present, day by day, and enjoy all the pleasures that are available to us in family, art, music, travel, and whatever pursuits make our lives meaningful and purposeful in the here and now.

Many people, including myself, have had personal religious experiences where they have had direct contact with God or visited heaven (near-death experiences). Those are empirical facts too.

How can you prove they where not just hallucinations, all in the head of the person claiming the experience? I can tell you how! All that has to happen is the subject returns with some knowledge that she could not have possibly known prior to the experience. For example, suppose she meets Jimmy Hoffa in heaven and he tells her where he is buried. When she reports that location, authorities go to the site and dig up a body that they identify as Hoffa by its DNA.

Nothing like this has ever happened in the thousands of religious experiences that have been reported over the centuries.

There is every reason to believe in God and no good reason not to. If you do, you have everything to gain and nothing to lose. (Pascal's Wager)

You can make the wager if you want, but that does not make God exist. If he doesn't, think of all the time and money you wasted going to church. But more than that, if God is a just God, wouldn't he be more likely to want to share eternity with someone who honestly disbelieved for lack of evidence than a liar who pretended to believe just to get his ass into heaven?

Many billions of people have a hunger for God. We have a "god-shaped hole" in out hearts. If there was no food, we would have nothing to be hungry about.

There are billions of people who do not feel any hunger for God. And, again, that hunger does not mean God exists. I hunger for that perfect pizza, but that doesn't make it exist by just thinking about it.

Believers are healthier and happier than nonbelievers.

Even if this were true it would not prove God exists. But it is not true. Indeed, the happiest and healthiest societies are the ones with the highest percentage of nonbelievers, such as Denmark and other Scandinavian countries. In the U.S., surveys show that atheists are happier and healthier than theists. Furthermore, careful scientific studies have failed to find any evidence that prayer improves health.

What about the studies showing that churchgoers are healthier than non-churchgoers?

Well, there is no smoking in church. And many people are too sick to go to church.

Actually, these studies are inconclusive since they do not compare churchgoers with a control sample of non-churchgoers with the same demographics. A scientific study that does not contain a proper control sample is worthless.

Just because there is no evidence for God, that does not mean he does not exist. Absence of evidence is not evidence of absence.

Absence of evidence is evidence of absence when it is evidence that should be there and is not. If the God most people worship existed we should have seen evidence for him by now. The fact that we do not proves, beyond a reasonable doubt, that he does not exist.

The more one studies religion objectively, the less one is likely to be religious. Surveys show that atheists know more about religion than theists. Many former evangelical preachers have written eloquently about how they lost their faith once they learned the truth about how the Bible came to be written and pondered the suffering in the world. I will just mention a few: Bart Ehrman, Dan Barker, and John Loftus. Many clergypersons are coming out of the closet now, no longer able to maintain their self-respect preaching the nonsense they have been taught to preach to their congregations. We are beginning to near that point where we can imagine no religion. When that happens, the world will be a better place.