How to Explain or Defend Atheism
Humans have a history of making up convenient explanations for things unknown. For example, some had thought the sun to be a living god; others believed (and a very small number still do) the earth to be flat and the center of the universe. In short, explanations based on gods and heaven have been steadily replaced as new knowledge is gained. History suggests that remaining mysteries will be sufficiently explained in terms of familiar and rational forces rather than by supernatural ones. For example, many people believe that a superior being created life, while atheists believe that this is just another scientific phenomenon to which people have assigned a supernatural explanation. People once believed that it was a choice between blind chance and a god creating living organisms; therefore, most educated people saw a need for a god. We now know that the random process of DNA mutation is coupled with the nonrandom process of natural selection. An atheist might want to point out that the scientific consensus is that the Big Bang, abiogenesis, and evolution account for the beginning of the universe and the origin and diversity of life. While this does not rule out the possibility of a
god's guiding the development of life, it does show that a god is not needed as an explanation for the origin of life.
Explain that 'intelligent design' (a pseudoscientific term used by creationists) is just the awe of new experience or of overwhelming complexity. It is a poor argument for a god. It is an argument from ignorance, a god-of-the-gaps argument, and as the gaps are filled, the god is gradually removed from the picture. If a caveman were handed a modern camera, he would not guess that it was a result of step-by-step gains in knowledge over a very long time. It would seem inexplicable, magical, perhaps supernatural. 'The gods must have made it' may be a natural thought, but it would be wrong. While a caveman might imagine that a god created the camera out of nothing (poof!), the camera would have been created through a number of steps, out of simpler parts. Living organisms are also made of many parts that developed gradually through evolution. A creationist may try to claim that the eye is an example of irreducible complexity, but unlike evolutionary biologists who have an explanation, creationists do not explain the mechanism that a god would use to create an
eye.
Clearly define faith or belief: some people have faith that there is a god. For some people, the existence of a god is a given (it can be automatically accepted), like the fact that the sun will rise tomorrow. This is a philosophical belief and is (as yet) untestable by science. An example of another philosophical belief not testable by science is the belief that we are living in a world created by a supercomputer to deceive our five senses (like in The Matrix). Since we use our senses to observe the world around us and to do science, there is no way for science to investigate such a belief. So far, all phenomena that have been explained (e.g., lightning, diseases, the origin of the universe and life) have had natural explanations rather than supernatural one. So far, a supernatural explanation has never won out. Supporting a supernatural explanation may be possible, but it would be extremely difficult, as all natural explanations would have to be first excluded. An atheist does not have faith in a god like some other people. An atheist argues that one must have a reason to believe in something before considering it.
Point out that there are many gods. Any theist, especially
monotheists like Christians, reject all gods but their own. You can point out that you simply reject one more god than they do.This is a useful point to make if you are trying to get a theist to relate to/understand your position but it's not so useful if your debate opponent knows what they're doing. If they say, "Why do you not believe in the Lord?" you can respond with, "Why don't you believe in Thor or Odin? To some people these gods are just as real as your own."
Recognize that religions, abstract from their gods, are important as social institutions. People clearly have an innate affinity for stories, akin to the popularity of movies, plays, legends, novels and ballads. Our willingness to believe in well-told stories (even supernatural ones) is a trait of human psychology. Religions influence behaviour through scripture and tradition presented with or without explanations. Evolutionary biologists have suggested that religion is either a result of the sophisticated human brain or was selected for due to a beneficial effect, such as promoting cooperation among people.
Clarify that to give up on a god does not mean you give up on morals. Atheists simply accept responsibility for
the moral code by which they live their lives. If you are feeling confrontational, contrast this sharply to the practice of accepting the moral code of the Bible. (following Yahweh's commands without question, regardless of what the commands are. Eg, slaughtering women and children.) You may also wish to familiarise yourself with "the euthyphro dilemma" and other related rebuttals in order to question their moral foundation. There are a variety of moral codes that an atheist can use, and they tend to be easy to explain.
Ask "Where did the god come from?" in response to "Where did the universe come from?" The main reason for positing a God is to explain where did life and the universe originate because they seem designed but positing a God just pushes the questions further away because how do we explain the existence of this God that just happens to have all of the power and answers - it is just as difficult and substitutes one problem for another and leads to an infinite regress. This line of thinking is of the sort of a hypothetical person happening upon a sandcastle on a beach and thinking that it would be silly to think that the waves built it - it must have been a person - but
alas who built the person? If a deity of unfathomable knowledge and power could just happen or just exist then why not take it a step back and consider that perhaps a Universe of unfathomable beauty and complexity just happened?
Remembering why we believe what we believe helps us keep actions in line with principles. These are typical atheistic positions on the most common challenges.