Atheism/Theism and Agnosticism – Definitions




In this essay I will explore the two major competing nomenclatures concerned with the definition of atheism, theism and agnosticism. Then I will argue that the new nomenclature is to be preferred. Then I discuss various issues with atheism/theism and agnosticism.

After that I reveal a questionnaire that one can use to determine one’s position according to the new nomenclature. I also reveal a table that shows the beliefs of the positions according to the new nomenclature.

The two nomenclatures

There are currently two major nomenclatures that concern the definitions of atheism/theism and agnosticism though there are also other less used ones.i First, let’s explore the old one.

The old nomenclature

I call it the ‘old nomenclature’ because it is the one that it currently dominant in both the common population and in the book-form dictionaries although online dictionaries and lexicons list both of them.ii

The possible positions are according to the old nomenclature:

  • Atheism means “the denial of the existence of God or gods.“iii
  • Theism means belief/faith in the existence of God or gods.
  • Agnosticism means either “the belief that there can be no proof either that God exists or that God does not exist.”iv or is the lack of belief “either way”.

This is how the terms are generally used in the old nomenclature. There are several competing versions of the old nomenclature.

The second definition of agnosticism is often not found in dictionaries but people use it, that is, they use “agnosticism”to mean “on the fence” or undecided about the question.

According to the old nomenclature there are three possibilities that one might be: an atheist, a theist and an agnostic. These are sometimes not mutually exclusive giving rise to joint positions such as agnostic theist and agnostic atheist.

The new nomenclature

I call it the new nomenclature simply because it is newer in origin than the old. It is getting more and more popular.

The possible positions are according to the new nomenclature:

  • “Atheism” means the lack of belief in God or gods.
  • “Weak/negative atheism” means the lack of belief ‘either way’.
  • “Strong/positive atheism” means the denial of the existence of God or all gods.
  • “Theism” means belief in the existence of God or gods.
  • “Agnosticism” means either the belief that there is no knowledge about God or gods, or the belief that knowledge of God or gods is impossible.

This is how the terms are generally used in the new nomenclature. There are several competing versions of the new nomenclature.

Weak vs. negative and strong vs. positive

“Weak atheism” and “strong atheism” is more commonly used than “negative atheism” and “positive atheism” respectively, but I prefer the latter pair. “Weak” and “strong” has connotations about how strong the belief is, or to what degree that it is held, or perhaps that the evidence for the belief is strong or weak, and this confuses people. “Weak” and “strong” also has another meaning in logic where a system is said to be weaker than another system if all the well-formed formula that are provable in that system is a proper subset of the other system.

Likewise “positive” and “negative” also has irrelevant connotations. “Positive atheism” can be understood to mean making something positive out of one’s lack of belief in god, e.g. by going to atheist conferences etc..v “Negative” atheism can be understood to mean that atheism has a negative valued influence on one’s life or something similar to that. However, “positive” and “negative” also have non-misleading connotations. With regards to definitions, as this is, a negative definition is sometimes said to be one that defines something as lack of other things. If we define “nothing” as “the lack of all things”, then the definition of “nothing” is negative. “Positive” is used to mean the opposite. These meanings carry over to the negative and positive atheism definitions sine negative atheism is indeed defined as the lack of something else, that is, belief and positive atheism is defined not as a lack of something.


The positive/negative distinction was or is used by philosophers such as Anthony Flewvi and Michael Martinviiviii and possibly more that I don’t know of. They see a lot of action on internet discussion boards.

Agnosticism and the three possibilities

According to the new nomenclature there are precisely two possibilities that one might be in relation to belief in God or gods: An atheist or a theist. Either one has belief or one hasn’t. An atheist is a person that has no belief in God or gods. A theist is a person that has.

Atheists come in two flavors, negative and positive. A negative atheist is a person who has no belief that God or gods exist, and no belief that God or gods do not exist. Note the difference between lacking a belief that God or gods exist, and believing that God or gods do not exist. More on this later. We may formalize the negative atheism position as ¬B(G)∧¬B(¬G), and the positive atheism position as B(¬G).

Why the new nomenclature is be to preferred

Why should we use the new nomenclature? I think there are multiple good reasons. First we should just note a couple of things we should desire from a nomenclature about something:

  • Exhaustiveness. There are only the possibilities listed in the nomenclature.

  • Exclusiveness. One can only have one position in the nomenclature.

  • Clear definitions and an easy to use methodology.

I’ll argue that the old nomenclature fails on the second point and the third point, while the new nomenclature does not.

Clear definitions and exclusiveness

I think the old nomenclature is unclear. It is not easy to tell which position one has even if one knows the nomenclature. The difficulty is to find out whether, according to the old nomenclature, one is an atheist or an agnostic. How would one go about doing that? I suppose one could ask oneself: Is there any god belief in my mind? If the answer is ‘yes’, then one is a theist. But if the answer is ‘no’ what is one then? An atheist? An agnostic? Both? It is not clear whether these two categories are mutually exclusive or not. Some seem to think they are and some seem to think they are not. Confusion is all around.

Agnostics are sometimes said to be the ones that are “unsure” whether God or gods exist. What exactly counts as “unsure? It appears that that has to do more with psychological certainty than belief which is the topic. This is perhaps why many have argued against a straw man when trying to criticize atheism (in the old nomenclature). They thought that atheism implies that one is 100% sure that there is no God or no gods but this is a confusion, atheism does not imply that. Neither theism or atheism have anything to do with certainty or justification for that matter. Many theists and atheists alike do not have proper justification for their beliefs and some theists and atheists alike do have proper justification for their beliefs.

Sometimes atheists and agnostics have been seen as one group, perhaps because it is hard, if one accepts the old nomenclature, to distinguish between them. It seems that the public still holds this view. At least if we assume that polls are fitted to the people they are polling. Polls or statistics usually include a joint “atheist/agnostic” category.ix

In my studies with ordinary non-philosophic people, which consisted of talking with them about whether they consider themselves atheists or theists or agnostics, most of them failed to distinguish between belief in not-p and the lack of belief in p. To be more clear: The question asked had the form: Do you believe that p? where “p” is any proposition (or sentence perhaps). They think that answering “Yes” implies that they believe in p (correct) but answering “No” implies that they have belief in not-p (incorrect). They fail to distinguish between non-belief in p and belief in not-p. They just mix them together. The problem is probably caused by a dumb language construction. Normally when we want to express that we believe that something is not the case we say “I don’t believe that p” when we really ought to say “I believe that p is not the case.”. It is very easy to see the difference between these two when we formalize them. The phrase “I don’t believe that p” is formalized as ¬B(P) and the phrase “I believe that p is not the case” is formalized as B(¬P). Clearly the negation is to be placed different places.

I think this language confusion is the primary reason why most ordinary people who are agnostics consider themselves agnostics.1

I also note that even though there is not exact clearness in the new nomenclature it is more clear than the old nomenclature and thus is to be preferred for this reason.

Other considerations: Etymology

It has been claimed that both the new and the old nomenclature “fits” the etymology better. I believe that neither fits it the best.

“Atheism” comes from the Greek “theos” which means god, and the prefix “a-” which can mean either “without” or “not”. So, “atheism” can mean, according to the etymology, either “without god” or “not-god”. The former can be interpreted as negative atheism in the new nomenclature and the latter can be interpreted as atheism in the old nomenclature and positive atheism in the new nomenclature.

But even if etymology showed that the original Greek word means only “no-god” or only “without god” it would be a fallacy to argue that so does the word also today. This fallacy is called the etymological fallacy.x A word’s etymology is a good guide to what a word means today but it is only probabilistic. Consider, as an example, the word “electronic”. It comes from the Greek word ‘elektro’ which means ‘amber’.xi

Issues with the new nomenclature

Two meanings of agnosticism

Another reason to prefer the new nomenclature is the proper definition of “agnosticism” within it.

Agnosticism” in newer philosophical literature usually means one of two things: What is called strong agnosticism which is the belief that no one can know whether God or gods exists, and what is called weak agnosticism which is the belief that no one currently knows whether God or gods exist. This distinction can be found both in online lexiconsxii and in works by philosophers.xiii

The new nomenclature is compatible with both of them, but in the questionnaire I have used agnosticism to mean weak agnosticism.

The scope of agnosticism

There is a scope problem in the definition of agnosticism. Who is it, exactly, that either lacks knowledge of God or gods, or that cannot have such knowledge? Is it oneself? All humans? All sentient beings? These are separate questions with perhaps separately answers. In the questionnaire

In the questionnaire I have set the scope of agnosticism to oneself.

The scope of atheism/theism

Should positive and negative atheism refer to all gods or just a specific god? This may strike one as a minor issue. Some people continue to employ their chosen version of the meaning of positive or negative atheism and think that that is what the term means. The fact is that the term is ambiguous. I think we can get rid of that ambiguity by distinguishing between the two different meanings. The most commonly meant scope of atheism is the set of normal gods, which are the most usually used god concepts. This excludes concepts such as pantheism and includes classical theism, the various versions of the christian god, the muslim god, the hindu gods etc. This is how I use the word atheism when it is not qualified. If needed one can qualify atheism by making it relative to a specific god or set of gods, e.g. the nordic gods. In the questionnaire I have used set the scope to the most common gods simply written as “gods”.

“Theism” however is usually taken to mean only belief in a single god. Belief in multiple gods is called polytheism.

Negative atheism and propositional attitudes

It is tempting to regard negative atheism as an attitude towards propositions, but this would exclude non-cognitivists, i.e. people who think that the sentence “a god exists” does not express any proposition. It results in a contradiction if we see consider non-cognitivists as negative atheists and that negative atheism is a propositional attitude since that implies that the sentence expresses a proposition and the non-cognitivist denies this. I think it is best to include non-cognitivists as negative atheists and so I have to find some way to make sense of it. It of course involves dropping the propositional attitude analysis of negative atheism. What might one replace it with? We shall not explore that now.

Knowing and believing that one knows

We colloquially say that agnostics are those who don’t know that a god exists, and that gnostics are the ones that does. What are we to do then we both atheists and theists call themselves gnostics? Either a god exists or it doesn’t, and so either some atheists know, some theists know or neither any atheist or any theist knows. It is not possible that both a theist and an atheist knows since that implies that a god exists and that a god does not exist. How are we to fit our nomenclature to this?

The answer is pretty simply. The nomenclature is to be about what one believes that one is, not what one actually is. So gnostics are those who believe that they know, and agnostics are those that don’t believe they know.


1. Do you believe that a god exists?

Yes. Go to 2.

No. Go to 3.

2. Do you believe that you know that a god exists?

Yes. You are a gnostic theist.

No. You are an agnostic theist.

3. Do you believe that no god exists?

Yes. Go to 4.

No. You are an agnostic negative atheist.

4. Do you believe that you know that no god exists?

Yes: You are a gnostic positive atheist.

No: You are an agnostic positive atheist.


This questionnaire assumes that the person does not hold contradictory beliefs about these matters. If this is not assumed one can be both a positive atheist and a theist etc.

Rigorous table

Position Belief that a god exists Belief that one knows that a god exists. Belief that no gods exist. Belief that one knows that no gods exist.
Gnostic theist T T F F
Agnostic theist T F F F
Agnostic negative atheist F F F F
Agnostic positive atheist F F T F
Gnostic positive atheist F F T T


This table assumes that the person does not hold contradictory beliefs about these matters. If this is not assumed one can be both a positive atheist and a theist etc.


iE.g. Drange’s. See Theodore M. Drange, Atheism, Agnosticism, Noncognitivism (1998),

ii Atheism. (2009, March 19). In Wikipedia, The Free Encyclopedia. Retrieved 19:32, March 19, 2009, from

iii The American Heritage® Dictionary of the English Language, Fourth Edition, 2006

iv The American Heritage® Dictionary of the English Language, Fourth Edition, 2006

vIndeed a major discussion board uses “positive atheism” exactly this way. See

vi Flew, Antony. “The Presumption of Atheism”. The Presumption of Atheism and other Philosophical Essays on God, Freedom, and Immortality. New York: Barnes and Noble, 1976. pp 14ff

vii Martin, Michael. The Cambridge Companion to Atheism. Cambridge University Press. 2006. ISBN 0521842700,

viii Martin, Michael (1990). Atheism: A Philosophical Justification. Philadelphia, PA: Temple University Press. ISBN 0-87722-943-0.

ixSee e.g. Zuckerman, Phil. “Atheism: Contemporary Rates and Patterns”, chapter in The Cambridge Companion to Atheism, ed. by Michael Martin, Cambridge University Press: Cambridge, UK (2005)

x Gary N. Curtis, The Etymological Fallacy,

xi Douglas Harper, Electric, Online Etymology Dictionary,

xii Strong agnosticism. (2008, September 30). In Wikipedia, The Free Encyclopedia. Retrieved 21:27, March 19, 2009, from

xiii Graham Oppy, Weak Agnosticism Defended, 1994,


1It’s a problem with many languages, including English and Danish, that it is hard to distinguish between a negative and a lack of a positive.

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