Agnosticism is the position that it is impossible to know many things especially questions surrounding the ultimate reality behind our existence, what happens to us when we die and the ontology (or intrinsic nature) of God. The question: 'what is God' must be a prerequisite to the question 'does God exist', because it makes no sense for one to try and prove the existence of something without defining what it is that one is trying to prove exists. The moment that the theist admits that they do not know what God is or what the nature of God is they have entered into the realm of Agnosticism. Gnosis is a Greek term that means ‘knowledge’ and for example Christian Gnostics claimed to have Esoteric Gnosis. The opposite is Agnosticism, or to claim to be without knowledge.
In order to understand the position of the agnostic one has to begin with the branch of philosophy called epistemology. Epistemology is simply the study of knowledge, how we know what we know and distinguishing what we know to be true from what we believe to be true. It is my firm perspective that anyone who humbles themselves and deciphers what they know compared to what they believe that they will inevitably arrive at agnosticism (the position that it is impossible to know many things) and hopefully as a result they will abandon organized religion.
In short knowledge should not be seen as simply the accumulation and memorization of information by the the cognitive processes of the brain. Rather knowledge in an epistemic context has more to do with concrete data that is justifiable, falsifiable, verifiable, repeatable and thus the data translates to a warranted belief through a rational and empirical methodology. In short we know what we know because we can observe and test what we know through the scientific method. Anything that cannot be tested, observed and rationalized through our individual and collective efforts is not knowledge rather unjustified belief.
What I would want the followers of any organized religion to focus on is what they do NOT know even if they have beliefs about the unknown. Metaphysical claims such as the existence of God, Angels, Demons,Jinn, Heaven and Hell should be categorized as unknowns. No one truly knows what they are. Hence they are outside of the scope of rationality. Beliefs in the occurrence of supernatural miracles however, such as Jesus walking on water or Muhammad splitting the moon, would be deemed irrational due to the fact that the claims are not metaphysical claims rather these are claims that directly have to do with the laws of physics that we do know. So there is rational, irrational and simply outside of the scope of rationality. While Theists can believe in a metaphysical reality the specific beliefs they have about metaphysical entities must be categorized as unknowns, unjustified beliefs, philosophical conjecture, and theoretical possibilities based on imagination. Beliefs in supernatural miracles however are different than beliefs in metaphysical realities and are irrational because the claim is made that the laws of physics as we know them are defied and there is no rational basis for this.
So allow me to demonstrate that Muslims and Christians are actually closet agnostics. In Islam there is this notion of Ilm al Ghayb (knowledge of the unseen). This knowledge of the unseen in a nutshell is the ultimate reality of all things and only God possesses this knowledge. God reveals this ‘ilm-al-ghayb’ to special individuals, namely the Prophets of God, however even the Prophets of God are limited in their capacity at truly knowing what the mystical things they have come to experience are. Generally through esotericism and mysticism individuals have claimed to have had experiences that gave them spiritual knowledge not otherwise known to collective humanity. However even if an individual claims such Esoteric Gnosis they still do not know what it is they have experienced. The experience is a mystery and therefore the only real Gnosis they have come upon is that there is a mystery beyond the biology, chemistry and physics of all that appears on the surface. In reality their inability to know what it is that they have experienced brings them right back to Agnosticism.
The moment the Muslim and Christian admits that they do not know what God is, what Angels are, what Jinn are etc. their beliefs collapse into agnosticism. There is a common discussion between the Purist/Literalist Salafi Muslims and the Ashari-Maturidi-Sufi Muslims. The purists will argue for example when the Qur’an describes the Divine in anthropomorphic terms that the true nature of the HANDS or FACE of God is unknown. Likewise, when the Qur’an mentions the ARSH or Throne of the Divine, which the Divine has ISTAWA or risen above (7:54), Muslims agree that the nature of the throne is simply unknown to collective humanity. The Ashari-Maturidi-Mu’tazili-Sufi types of Muslims will try and apply a metaphorical interpretation, but in the end agree with the Purists that the true nature of the Throne or Hands of God are unknown. Again, when one breaks down the theological perspective of Muslims and Christians not really knowing something, especially about what God is, what we find is that they are falling into the category of agnosticism. Therefore their agnosticism cannot be superior to anyone else's agnosticism.
Epistemology totally recognizes that people have beliefs about unknown. In effect there are three types of Agnostics. Agnostic Theists, Agnostic Atheists and Agnostics who don’t care. Agnostic Theists have beliefs about God but ultimately admit that they don’t know what God is or what God ‘wants’ (if God wants anything at all). Agnostic Atheists admit that they cannot prove a negative or prove that God (or any metaphysical entity) does not exist but they believe that most of the evidence points to there not being a God (at least the gods that organized religions describe). The third category is self explained.
Two beautiful sources for agnosticism in past human civilizations include Greek philosopher Socrates and Chinese philosopher Laotzi. The latter is known as the Father of Daosim and author of the Daodejing where he writes as follows:
The Dao that can be described is not the absolute Dao;
the name that can be given is not the absolute name.
Nameless it is the source of heaven and earth;
From Laotzi comes the approach of an unknowable God. The idea that any description that any one gives about God simply cannot really be what God is. However the notion that one can interact with oneself and the environment spiritually (i.e. interact with God) and not knowing the ontology or nature of that spiritual experience are two different issues.
The story of Socrates is a bit more inspirational. Here you have an individual who goes to an Oracle that makes a bold statement: no one is as wise as Socrates. Now pay attention to the fact that the Oracle did not say that Socrates is the WISEST, rather the statement was that no one is as wise as Socrates. This message from the Oracle is something that Socrates himself struggled with because Socrates himself believed that he had no wisdom at all. He claimed that he had no knowledge. Eventually he came to realize what was meant by that statement. Socrates was taken to court for “corrupting the youth” and for denying the religion/gods of the Greeks. Socrates went to the people regarded as wise in the community, namely the politicians, artisans and poets in order to prove the Oracle wrong. What Socrates realized from his experiences was that while each individual he encountered had some wisdom in terms of their trade that they actually did not know more than him in terms of life’s big questions. Finally Socrates had come to realize what the Oracle meant. Socrates admitted that he knew nothing. Admitting to ignorance is in fact the ultimate wisdom that he had and therefore no one was wiser than Socrates. Socrates was sentenced to death due to his “blasphemy”. This story of Socrates being killed for standing up for Philosophy is far more intellectually and spiritually inspirational than that of Jesus who was killed for making erroneous metaphysical claims.
In any event I hope from the bottom of my heart that Muslims and Christians seriously reflect, humbly admit, openly embrace and effectively grow from their inevitiable position of not knowing. Once they do that they will have renounced their position of wanting to implement and force their religion on others and especially their position that they have arrived at some type of exclusive understanding and absolutism concerning reality and existence.