Does morality prove the existence of God? 

Religion is frequently held up as a model of correct or moral behavior. Many holy books contain rules for how people must live in order to reach Heaven or some similar blessed afterlife, and failure to follow those rules often means eternal banishment and punishment. A person who follows these rules and is "godly" is also presumed to be a moral, upright person, whereas atheists are frequently viewed with suspicion. After all, with no god to tell you how to behave, what's to stop a person from doing whatever she wants? One poll conducted by Canadian psychologists even placed atheists as more untrustworthy than rapists in the United States and Canada, showing that atheists are among the least trusted people even in North America ⁽¹⁾.

In reality, there's no evidence that atheists as a group are any more untrustworthy or immoral than any other group. There are dishonest atheists just as there are dishonest Christians and Muslims, and there are atheists who are paragons of good behavior just like any upstanding religious person.

Indeed, religions do seem to incite violence ^{(2) (3)}. This does not always imply a direct causal relationship between religion and violence, yet, this is the opposite of what you'd expect if morality really did stem from God.

Morals Change and Fall Out of Fashion

Religious texts are generally ancient, and they reflect the values of the times when they were written. Over time, our views of what is acceptable shift as our cultures progress, which makes many things found in the Bible or Quran seem outdated and highly problematic.

Consider, for example, the issue of slavery. Although there are some people who still believe that slavery is moral, the vast majority of modern Christians are unlikely to admit support for the ownership of another person. Nevertheless, the Bible has many references to slavery, carefully detailing the rules for proper slave ownership.

For example, in the Old Testament, Leviticus 25:44-46 explains that you can take slaves from neighboring nations but not enslave your own people: “Your male and female slaves are to come from the nations around you; from them you may buy slaves.” Exodus 21:20-21 helpfully clarifies that a slave-owner will be punished if he strikes a slave but only if the slave dies within a few days of the punishment: “they are not to be punished if the slave recovers after a day or two, since the slave is their property.”

Slavery isn't the only questionable practice condoned in the Bible. The death penalty was also wielded quite liberally in biblical times, and death was a popular punishment for sins in the Old Testament, including violations such as adultery (Leviticus 20:10), homosexuality (Leviticus 20:13), lying about virginity (Deuteronomy 22:13-21), breaking the Sabbath (Exodus 31:14-15), cursing your parents (Exodus 21:17) and more.

In Islamic teaching, it’s made quite clear that anyone who turns away from the Islam should be put to death. Within some of the most trusted and authoritative Hadith collections in Islam, which is the main source of Islamic laws and ethics, Prophet Muhammad is quoted as calling for the death penalty against apostates:

The Prophet said, "The blood of a Muslim who confesses that none has the right to be worshipped but Allah and that I am His Apostle, cannot be shed except in three cases: In Qisas for murder, a married person who commits illegal sexual intercourse and the one who reverts from Islam (apostate) and leaves the Muslims." (Sahih al-Bukhari, Vol. 9, Book 83, Hadith 17)

The Quran also advocates beating wives when they misbehave:

“Men are in charge of women by [right of] what Allah has given one over the other and what they spend [for maintenance] from their wealth. So righteous women are devoutly obedient, guarding in [the husband's] absence what Allah would have them guard. But those [wives] from whom you fear arrogance - [first] advise them; [then if they persist], forsake them in bed; and [finally], strike them. But if they obey you [once more], seek no means against them. Indeed, Allah is ever Exalted and Grand.” (Quran 4:34)

Of course, many religious people are quick to jump to the defense of their given holy book by insisting that passages like those mentioned above are taken out of context. The claim is that critics of religion ignore the verses that come before and after and by doing so, the verses seem to mean something that they are not intended to mean. Yet many critics have actually taken the time to study these verses within their context and with a great deal of detailed analysis. It is recommended that you do not use any of these verses in an argument before studying the context in which they were mentioned in. Curiously, many believers do not demand more context when mentioning verses describing love, charity or any other positive aspect of their scripture; verses are only viewed as being out of context when the content is unflattering for believers. This sort of cherry picking is a convenient viewpoint to hold but certainly not a defensible one.

While the punishments and habits described above may have fit into the accepted morals of the authors’ time and cultures, that doesn’t make those cultural practices acceptable today. Today, a man who kills his wife for lying about her virginity would be persecuted as a murderer, not lauded for his moral behavior. If morality truly stemmed from an all-powerful deity, it would not change over time.

The Euthyphro Dilemma

Are things moral simply because God says so? Or does God give certain orders because they are inherently moral? This is the question at the core of Plato's Euthyphro dilemma, a problem that lies at the heart of religious debates about the divinity of moral authority ⁽⁴⁾. If morality exists separate from God's will, there is no reason to rely on God for moral behavior; one could have moral standards independently without divine feedback. On the other hand, if God creates morality simply by saying whether something is right or wrong, then that’s not really morality; it’s arbitrariness. Morality would become nothing more than the whimsy of a divine being blindly followed by humans.

God is Either Impotent, Evil or Non-existent

Most religions claim an all-powerful, all-loving benevolent deity. However, physical reality often contradicts this claim. Terrible things happen to people every day. Children die tragically young, natural disasters wipe out whole communities and people die from accidents and disease. These do not suggest a righteous and compassionate god. These suggest that God is either powerless, cruel or non-existent.

Worse still is the concept of hell, where non-believers suffer in eternal torment simply for disbelieving in God. Indeed, this torture is supposedly granted even to theists who believe in the wrong gods. If the Christian religion is the “right” one, every Muslim, Hindu, Buddhist and Jew would burn in hell for eternity (John 3:18-36, 2 Thessalonians 1:6-10 and Revelation 21:8), and this rule is the same for other religions that believe in the concept of hell, such as Islam:

And whoever desires other than Islam as religion - never will it be accepted from him, and he, in the Hereafter, will be among the losers. (Quran 3:85)

Lo! Those who disbelieve Our revelations, We shall expose them to the Fire. As often as their skins are consumed We shall exchange them for fresh skins that they may taste the torment. (Quran 4:56)

They surely disbelieve who say: Lo! Allah is the Messiah, son of Mary…for him Allah hath forbidden paradise. His abode is the Fire... They surely disbelieve who say: Lo! Allah is the third of three; when there is no Allah save the One Allah. If they desist not from so saying a painful doom will fall on those of them who disbelieve. (Quran 5:72-73)

For them is drink of boiling water and a painful doom, because they disbelieved. (Quran 6:70)

And the dwellers of the Fire cry out unto the dwellers of the Garden: Pour on us some water or some wherewith Allah hath provided you. They say: Lo! Allah hath forbidden both to disbelievers (in His guidance). (Quran 7:50)

If thou couldst see how the angels receive those who disbelieve, smiting faces and their backs and (saying): Taste the punishment of burning! (Quran 8:50)

We shall assemble them on the Day of Resurrection on their faces, blind, dumb and deaf; their habitation will be hell; whenever it abateth, We increase the flame for them. That is their reward because they disbelieved Our revelations. (Quran 17:97-98)

Lo! We have prepared for disbelievers Fire. Its tent encloseth them. If they ask for showers, they will be showered with water like to molten lead which burneth the faces. Calamitous the drink and ill the resting-place! (Quran 18:29)

But as for those who disbelieve, garments of fire will be cut out for them; boiling fluid will be poured down on their heads, Whereby that which is in their bellies, and their skins too, will be melted; And for them are hooked rods of iron. Whenever, in their anguish, they would go forth from thence they are driven back therein and (it is said unto them): Taste the doom of burning. (Quran 22:19-22)

And those in the Fire say unto the guards of hell: Entreat your Lord that He relieve us of a day of the torment. They say: Came not your messengers unto you with clear proofs? They say: Yea, verily. They say: Then do ye pray, although the prayer of disbelievers is in vain. (Quran 40:49-50)

An all-loving god would surely not damn his children to an eternity of torture simply for being born into a culture that believes in the wrong deity, follows the wrong holy book or attends the wrong type of church services.

In a debate about morality and the Christian religion, Sam Harris points out the double standard in the idea of an all-benevolent god ⁽⁵⁾. When something good happens to a believer, believers often attribute that to God. When a disaster occurs, believers often explain that God's will is mysterious and cannot be comprehended by mortals. These two claims are in opposition; if God's will cannot be comprehended, how do we know that he has good intentions at all? It certainly does not lay a solid foundation for the claim of God as the ultimate source of morality.

A Natural Explanation for Morality

As science explores the nuances of human relationships, it becomes clear that morality can exist outside of religion. In fact, it's not even limited to humans. Altruistic behaviors have been observed in animals, particularly those with complex social structures ⁽⁶⁾.

Our brains have evolved with behavioral strategies that help the survival of our genes. This is responsible for selfish desires that have helped the survival of our species, but it has also lead to altruistic desires, such as sympathy or the desire for fairness. Such natural desires have improved the survival of our genes by increasing cooperation among individuals ⁽⁷⁾.

Social animals, including humans, behave in certain ways toward others because their brains have evolved to help to ensure not only their own survival, but also the survival of their genetic kin. To make us behave in such a way, our brains create feelings, such as sympathy and desire for fairness, that are hardwired in our brains ⁽⁷⁾. As Samir Okasha of the Department of Philosophy at the University of Bristol explains: “Contrary to what is often thought, an evolutionary approach to human behavior does not imply that humans are likely to be motivated by self-interest alone. One strategy by which ‘selfish genes’ may increase their future representation is by causing humans to be non-selfish, in the psychological sense” ⁽⁶⁾.

Our genes are not conscious. They did not have the foresight to optimize our desires for maximizing human flourishing in modern societies; hence, fully relying on our altruistic desires is not ideal. But humans are capable of conscious foresight and thus are able to design a more comprehensive set of standards.

Ultimately, moral standards, as we understand them, are social constructs. They are tied intimately to cultural circumstances and can change over time. Nevertheless, the source of these standards is rooted in sentiments such as sympathy towards our fellow conscious beings and a desire for living in a peaceful and cooperative society. Social constructs that are based upon such desires are, at their best, designed for maximizing human flourishing while utilizing our evolutionary desires to encourage them. Given that these desires are intimately tied to our brain states, maximizing the level of happiness for the most number of people can be best achieved by a scientific understanding of how our brains function and understanding what set of standards can best encourage more human interactions that lead to a functional society ⁽⁸⁾. 

References:

1. Gervais, Will M., Azim F. Shariff, and Ara Norenzayan. "Do You Believe in Atheists? Distrust Is Central to Anti-Atheist Prejudice." Journal of Personality and Social Psychology 101, no. 6 (2011): 1189-206.
2. Ellens, J. Harold. The Destructive Power of Religion: Violence in Judaism, Christianity, and Islam. Westport, Conn.: Praeger, 2003.
3. Hall, John R. "Religion and Violence from a Sociological Perspective." The Oxford Handbook of Religion and Violence, 363-374. Oxford: Oxford University Press, 2013.
4. Jowett, Benjamin. "Euthyphro by Plato." The Internet Classics Archive. Accessed September 4, 2014.
5. Harris, Sam. "Is the Foundation of Morality Natural or Supernatural? The Craig-Harris Debate." ReasonableFaith.org. April 7, 2011. Accessed September 4, 2014.
6. Okasha, Samir. "Biological Altruism." Stanford University. June 3, 2003. Accessed September 5, 2014.
7. Dawkins, Richard. The Selfish Gene. 2nd ed. Oxford: Oxford University Press, 1990.
8. Harris, Sam. The Moral Landscape: How Science Can Determine Human Values. New York: Free Press, 2010.