The logic of science-1: The basic ideas

(For other posts in this series, see here.)

In the course of writing these blog posts, especially those dealing with religion, atheism, science, and philosophy, I have often appealed to the way that principles of logic are used in science in making my points. But these are scattered over many posts and I thought that I should collect and archive the ideas into one set of posts (despite the risk of some repetition) for easy reference and clarity. Besides, I haven’t had a multi-part series of posts in a long time, so I am due.

Learning about the principles of logic in science is important because you need a common framework in order to adjudicate disagreements. A big step towards in resolving arguments can be taken by either agreeing to a common framework or deciding that one cannot agree and that further discussion is pointless. Either outcome is more desirable than going around in circles endlessly, not realizing what the ultimate source of the disagreement is.

When people seek definite knowledge, they turn to science, not religion. For all its claims of revealing timeless truths, religion completely fails to deliver the goods. Nobody except religious fanatics seek answers to empirical questions in their religious texts, whereas the power and reliability of science is such that people accept completely counter-intuitive things as true, as long as a scientific consensus can be invoked in support of it. For example, the idea that stars are flaming hot gases is by no means self-evident, and yet everyone now accepts it. The idea that entire continents move is also accepted even though we cannot sense it directly. How does science get such persuasive authority? In this series of posts, I will examine how it can be so successful.

A good example of how the logic of science works is to see how the advance of science has made it quite obvious that there is no god. But it is important to be clear about how that conclusion is reached. Science has not proved that there is no god, can never prove that there is no god, and does not need to prove that there is no god. So why is it that so many scientists are so confident that god does not exist? It is really very simple. While the logic of science is such that it can never prove the non-existence of whatever entity that one might like to postulate, what it has shown is that god is an unnecessary explanatory concept for anything. It is just like the ether or caloric or phlogiston, scientific concepts that ceased to be necessary explanatory concepts, making them effectively non-existent. God has joined the ether, caloric, and phlogiston in the trash heap of discarded knowledge.

You would think that this simple point would be easy to understand. But as the cartoon below by Jesus and Mo shows, religious people somehow don’t seem to get this simple point, perhaps because it throws their own arguments for a loop. They seem to willfully misunderstand it, perhaps so that they can continue to argue against straw men. So let me repeat it for emphasis: Science has not proved, and can never prove, that there is no god. Science is not in the business of proving and disproving things. What it has shown is that god is an unnecessary explanatory concept.


A big source of confusion about the logic of science comes from religious believers in their efforts to create some wiggle room for them to claim that believing in god is rational. What they try to argue is that even if there is no evidence for god, it is still reasonable to believe in he/she/it. Some religious people claim that since we cannot logically or empirically prove that god exists or does not exist, taking either point of view is an act of faith on an equal footing.

This is flat-out wrong because the logic of science is different from the logic of mathematics or the logic of philosophy because evidence is an essential ingredient in science. In science, logic does not remain in the abstract but is applied to data. When it comes to empirical questions such as whether any entity (including god) exists, the role of logic is to draw inferences from evidence. In the absence of evidence in favor of existence, the presumption is nonexistence.

We believe in the existence of horses because there is evidence for them. We do not believe in the existence of unicorns (or leprechauns, pixies, dragons, centaurs, mermaids, fairies, demons, vampires, werewolves) because there is no evidence for them even though we cannot logically prove they do not exist. It really is that simple. Anyone who argues that it is as reasonable to believe in god as it is to not believe in god is forced, by their own logic, to assert that it is as rational to believe in the existence of unicorns, etc. as it is to not believe in them.

The only time one encounters this type of ‘logic’ is from people who are defending god, the afterlife, and all the other forms of magical thinking that they cannot bear to give up and cannot defend in any other way.

So what follows in this series of posts is my attempt to clarify some of the underlying logical principles on which science functions and why one can confidently say that, applying the logic of science, the only reasonable conclusion has to be that god does not exist. I have few illusions that it will persuade religious people to give up belief. As the TV character House said, “Rational arguments don’t usually work on religious people. Otherwise there would be no religious people.”

My goals are more limited and that is to enable atheists to more effectively expose the fallacious arguments of religious believers and to facilitate more meaningful discussions about the role of science in arriving at firm conclusions about things. Over time, as religious believers find their assertions firmly challenged by others in every sphere of life, we will see an accelerating erosion of belief.

Next in the series: Determining truth

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