Dennis Prager (one of my favourite political commentators) has an excellent article in Front Page Magazine. I am reprinting most of it.
For the full article go to the Source
So, while it is not possible to prove (or disprove) God's existence, what is provable is what happens when people stop believing in God.
1. Without God there is no good and evil; there are only subjective opinions that we then label "good" and "evil." This does not mean that an atheist cannot be a good person. Nor does it mean that all those who believe in God are good; there are good atheists and there are bad believers in God. It simply means that unless there is a moral authority that transcends humans from which emanates an objective right and wrong, "right" and "wrong" no more objectively exist than do "beautiful" and "ugly."
2. Without God, there is no objective meaning to life. We are all merely random creations of natural selection whose existence has no more intrinsic purpose or meaning than that of a pebble equally randomly produced.
3. Life is ultimately a tragic fare if there is no God. We live, we suffer, we die -- some horrifically, many prematurely -- and there is only oblivion afterward.
4. Human beings need instruction manuals. This is as true for acting morally and wisely as it is for properly flying an airplane. One's heart is often no better a guide to what is right and wrong than it is to the right and wrong way to fly an airplane. The post-religious secular world claims to need no manual; the heart and reason are sufficient guides to leading a good life and to making a good world.
5. If there is no God, the kindest and most innocent victims of torture and murder have no better a fate after death than do the most cruel torturers and mass murderers. Only if there is a good God do Mother Teresa and Adolf Hitler have different fates.
6. With the death of Judeo-Christian values in the West, many Westerners believe in little. That is why secular Western Europe has been unwilling and therefore unable to confront evil, whether it was Communism during the Cold War or Islamic totalitarians in its midst today.
7. Without God, people in the West often become less, not more, rational. It was largely the secular, not the religious, who believed in the utterly irrational doctrine of Marxism. It was largely the secular, not the religious, who believed that men's and women's natures are basically the same, that perceived differences between the sexes are all socially induced. Religious people in Judeo-Christian countries largely confine their irrational beliefs to religious beliefs (theology), while the secular, without religion to enable the non-rational to express itself, end up applying their irrational beliefs to society, where such irrationalities do immense harm.
8. If there is no God, the human being has no free will. He is a robot, whose every action is dictated by genes and environment. Only if one posits human creation by a Creator that transcends genes and environment who implanted the ability to transcend genes and environment can humans have free will.
9. If there is no God, humans and "other" animals are of equal value. Only if one posits that humans, not animals, are created in the image of God do humans have any greater intrinsic sanctity than baboons. This explains the movement among the secularized elite to equate humans and animals.
10. Without God, there is little to inspire people to create inspiring art. That is why contemporary art galleries and museums are filled with "art" that celebrates the scatological, the ugly and the shocking. Compare this art to Michelangelo's art in the Sistine chapel. The latter elevates the viewer -- because Michelangelo believed in something higher than himself and higher than all men.
11. Without God nothing is holy. This is definitional. Holiness emanates from a belief in the holy. This explains, for example, the far more widespread acceptance of public cursing in secular society than in religious society. To the religious, there is holy speech and profane speech. In much of secular society the very notion of profane speech is mocked.
12. Without God, humanist hubris is almost inevitable. If there is nothing higher than man, no Supreme Being, man becomes the supreme being.
13. Without God, there are no inalienable human rights. Evolution confers no rights. Molecules confer no rights. Energy has no moral concerns. That is why America's Founders wrote in the Declaration of Independence that we are endowed "by our Creator" with certain inalienable rights. Rights depend upon a moral source, a rights giver.
14. "Without God," Dostoevsky famously wrote, "all is permitted." There has been plenty of evil committed by believers in God, but the widespread cruelties and the sheer number of innocents murdered by secular regimes -- specifically Nazi, Fascist and Communist regimes -- dwarfs the evil done in the name of religion.