July 06, 2011

The logic of science-1: The basic ideas

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


Trackback URL for this entry is:


Professor, I think you are oversimplifying. The "evidence" the religious find for God is the Universe, whereas there is no such "evidence" for the other mythical entities you listed.

Posted by healthphysicist on July 6, 2011 11:37 AM


The point above was whether, in the absence of evidence for its existence, whether it was as reasonable to believe in existence of an entity as it was in its non-existence. My answer was no.

Evidence is key in establishing existence but the statement "the universe is evidence for God" has no content. One could just as easily replace the word 'universe' with the word 'rose' or 'worm' or anything else. You have to show why it counts as evidence for your claim. What is it about the universe/rose/worm/other that gives god's existence credibility?

Posted by Mano on July 6, 2011 12:22 PM


To the religious, one could replace "Universe" with "rose" or "worm". (It's just that the "Universe" takes those things and all other known things into account.)

It counts as evidence to their claim, from their perspective, because they've defined God as the creator of what exists. And that's why the existence of anything in the Universe counts as evidence for their claim.

Non-religious people counter this "logic" with the anthropic principle. But to the religious, the anthropic principle doesn't provide any real explanatory power ("things are the way they are", isn't much of an explanation).

To an atheist, Goddidit doesn't provide any real explanatory power.

(Just to be clear...I'm an atheist)

Posted by healthphysicist on July 6, 2011 01:07 PM

Hi Mano,

I have found a lot of benefit explaining the logic/rationale of science by bringing in the idea of philosophical/epistemological pragmatism, especially when interpreted in relation to the ability to make useful predictions.

I've received some pretty good feedback about this article I wrote to explain the connection between pragmatism and prediction, and how that relates to science:

I hope you find it useful! ;-)

Posted by Wonderist on July 6, 2011 10:58 PM

It counts as evidence to their claim, from their perspective, because they've defined God as the creator of what exists.

No, you're quite confused. In your comment you, unlike theists, are treating the universe itself as "god" (which is Spinozism- logically indistinguishable from atheism and hardly something theists would endorse), not as the creation of "god".

Posted by Steve LaBonne on July 7, 2011 09:02 AM

No, you're quite confused. I'm treating the Universe as evidence of god. I'm not treating the Universe as if it were god.

Posted by healthphysicist on July 7, 2011 09:09 AM

I'm treating the Universe as evidence of god.

Not only is that nonsense (the mere existence of a thing is not evidence for any particular theory of its origin), it's not at all what you originally wrote. You're VERY confused.

Posted by Steve LaBonne on July 7, 2011 10:02 AM


I originally wrote:

"The "evidence" the religious find for God is the Universe..."

You are very confused.

Posted by healthphysicist on July 7, 2011 01:30 PM

Mano, I am curious about why you use the word "definite" in reference to knowledge. It seems as though you are writing that we can find absolutes, when we are aware that the knowledge that we gain through science is contingent.

Do you mean it as 'pragmatic?'

Posted by Mike Haubrich on July 8, 2011 03:04 PM


I meant knowledge that one can rely on and so 'reliable' is what I should have written.

Posted by Mano on July 8, 2011 09:30 PM