One of the more common criticisms I've heard directed at atheists is that in order to be an atheist, one must claim to know everything that exists in the universe and beyond. That is, in order to claim that no gods exist, one must possess all knowledge about everything that could possibly exist. Since obviously no human could possibly know everything that exists, it is argued that atheists are simply dishonest and arrogant.
While there may be atheists who make such claims, the vast majority do not. This is actually a misunderstanding of atheism on the part of believers who offer this criticism. The majority of atheists do not in fact assert that no gods exist. Most are actually agnostic, and simply remain unconvinced that any particular god exists.
However, in this article I want to go a bit further and put forward some arguments for why it may well be more rational to believe that no gods exist, at least for all practical purposes.
When we talk about gods, what are we really talking about? Many believers tend to play a bit of a bait-and-switch game with the term "god", where on the one hand they're talking about a vague deistic notion of a creative force or "intelligence" elsewhere in the cosmos, and next minute they're talking about a loving, all-knowing, all-powerful creator person who understands each of us personally and wants a relationship with us. These are very different concepts, and we should really be more specific when talking about gods, in order to avoid this confusion.
That's why I think it's important to try to limit the scope of what we mean when we ask whether there is a god. By ruling out gods that are for all practical purposes irrelevant to us, we can narrow down the search for any actual gods we should care about.
Not the gods you're looking for
There are a number of conceptual "gods" that would easily fit into the category of "creator" or "intelligence" but are completely contradictory to the gods most believers believe in, and are definitely not the God Christadelphians believe in.
For example, suppose the universe really was created by some sort of creative force, like a universe factory. Perhaps all it does is create universes and let them go. Such a force barely even meets the definition of a god (whatever that is - I will return to definitions at the end). It has no intentions or purpose, and perhaps no intelligence. Aside from the initial creation of the universe, it does not interact with us in any way.
As another example, imagine a powerful being that created the universe as a kind of experiment, but was unable to interact with anything inside it. Such a being could be described as personal, intelligent, and even the creator of the universe, but it has never communicated with us, and nor can it.
Imagine a powerful, loving creator god whose last act of love was to die in a burst of energy that gave birth to the universe. Again we have a being with many attributes of a god, but in this case it no longer exists.
The list of such "gods" is probably endless, and yet each is just as (im)probable as the next, including the god(s) people believe in and worship today. The odds of any believer being correct just on chance alone is effectively zero.
But should we be concerned about any of these gods existing? Of course not. Even if they existed, it would make no difference to us. That's why I mentioned "for all practical purposes" above.
When believers talk about the possibility of there being a god, they are not talking about these types of gods. In fact I would argue that most believers, along with atheists, don't believe in any of these impersonal gods, and thus they don't take the idea very seriously.
So when I argue that a god probably doesn't exist, I am not talking about these kinds of "gods". Any "god" that doesn't interact with us is completely irrelevant to us, and we to it.
Now that we've ruled out any god that doesn't interact with us, that necessarily leaves us with gods that do interact with us in some way.
What about an invisible being that exists everywhere in the universe but is indistinguishable from the laws of nature? Such a being would have exactly the same characteristics as the predictable natural processes we observe every day, such as gravity and thermodynamics. Would we worship the law of gravity? Hardly. Do General Relativity or Quantum Mechanics respond to prayer? Not in any way we can measure.
Ok, well what about an invisible being that exists independently of physical reality, in some form that our finite senses and equipment are unable to detect? What about a being that exists outside of time and space? Just because we cannot detect it, doesn't mean it doesn't exist.
Well ok, but now we have a new problem. If we cannot detect this being in any way, how did anyone discover it was there in the first place? A world inhabited by such an undetectable god would look exactly the same as a world inhabited by no god at all. Anyone claiming to have detected such a god would need to provide clear evidence. Many such claims have been made throughout history by people from many different religions, but no such evidence has ever been reliably confirmed. Worse, most religions actually contradict each other, and many of them admit outright that their god's existence cannot be verified by any empirical test.
Without some reliable, repeatable way to detect a god, we have no way to know it exists. To put it another way, all of the available information we have is entirely consistent with the non-existence of any gods. Gods that we have no way of detecting are therefore indistinguishable from gods that don't exist. For all practical purposes, it's the same thing.
The unknown god
So now we've ruled out gods that don't interact with us, and also gods that we are unable to detect. But what if there exists a god that we could conceivably detect if only we had the right equipment?
In Acts 17 we read about an altar in Athens with the inscription, 'To an unknown god'. The idea is the same. We are effectively asking, "What if there is a god out there, but we just haven't found it yet?"
How much energy should we spend worrying about a hypothetical god that no one has detected yet, just on the off chance that someone might detect it in the future? Not much, in my opinion. Believers seem to agree, since virtually none of them are concerned about the prospect of discovering a new god in the future.
If we're talking about a god that wants to be known, and has the means to make itself known to us (in an unambiguous way), then either that god will make itself known to us, or it doesn't exist.
The final cut, with definitions
Earlier I mentioned definitions. Unfortunately, most believers seem reluctant to offer testable definitions for their god(s). Instead they come up with vague terms like "all-knowing" and "all-powerful". But these attributes cannot all apply because they are self-contradictory.
For example, consider the popular criticism, "Can God create a rock so big he cannot lift it?" Or what about the question of whether an all-knowing god could know what it's like to not know something? The concepts of omnipotence and omniscience are incoherent. Therefore we can confidently rule out any god with such characteristics.
In response to these criticisms, some Christian apologists have gone with watered-down versions of God, inserting the words "logically possible" into the definition. Thus God would not need to know what it's like to not know something, because that would not be logically possible. But again we run into problems. It is not logically impossible for an all-powerful being to commit suicide. Can the Christian god do that? Perhaps it already has.
Further, it is logically impossible for an all-knowing god to have free will. So either it is all-knowing, or it has free will, but not both. Perhaps it has neither.
By now we've reached the point where we can start to think about how to define a god so as to incorporate everything covered so far in this article.
Put simply, in order for us to reliably confirm the existence of a god, it needs to interact with us in some measurable, unambiguous way, and it must have attributes that are self-consistent. But such verification has never occurred. There is no test that can reliably confirm the existence of a god. Further, believers disagree on virtually every aspect of the gods they worship, which suggests that their respective deities are not as detectable as the believers claim.
Which god is left?
The purpose of this article is to show that one does not need to possess infinite knowledge in order to rule out many conceptual gods "for all practical purposes".
In summary, any god that cannot or does not interact with me is irrelevant to me. Any god that I am unable to detect in any reliable way is also irrelevant to me. Any god that is detectable in principle, but not in practice, is irrelevant to me. Any god that hides itself from me, is not detectable in practice, and is therefore irrelevant to me. The only god I would ever need to concern myself with is one that is reliably detectable by me, and wants me to know it exists. I know of no such being.
Many believers claim that their favourite god is indeed detectable, but if so I have yet to discover any test that will reliably detect such a god. Conversely, some believers claim that their god cannot be tested, but an untestable god is an undetectable god. Back to square one.
What about a god that would be detectable by me, and wants me to know it exists, but for whatever reason it lacks the ability to show itself to me? I'm not sure such a being would be all that useful to me. Would it even know I exist?
Are there any gods left? This place is looking rather empty.
In closing, if you still think infinite knowledge is required in order to justify the belief that a god probably doesn't exist, just know that the same would apply to belief in the non-existence of unicorns, goblins, ghosts, leprechauns, the Flying Spaghetti Monster, Zeus, Thor, Odin, and every other god ever worshipped. If you believe that any of those beings probably don't exist, then you already know why I believe your god probably doesn't exist too.