I think philosopher William L. Rowe describes agnosticism well. He says an agnostic is someone who neither believes nor disbelieves in the existence of God, while a theist believes that God does exist and an atheist believes that God does not exist. English biologist T.H. Huxley coined the term agnosticism in 1869, but the concept was expressed way before that. It goes back to the Greeks around 450 BC and even earlier mentions are recorded in the Hindu Vedas, written between 1700 and 1100 BC. The word agnosticism means “without knowledge” and refers to the agnostic’s unyielding tenet that you can never know for certain that God exists.
Agnosticism has sometimes been divided into two categories: STRONG AGNOSTICISM which is the view that the existence of God is completely unknowable because the nature of God and faith is far too subjective and unscientific and lacks empirical evidence. WEAK AGNOSTICISM is the view that the existence of God is unknown but is not necessarily unknowable; further evidence is needed.
How do you answer an agnostic?
FACTS: Agnostics have great minds and follow strong arguments from brilliant minds of old. Perhaps facts regarding the veracity of the Bible will be of benefit to them. Fulfilled prophecy, archaeological evidence, apologetic studies, and the like might appeal to their sense of reasoning. (Isa 1:18) “Come now, and let us reason together,” says the Lord . . .
FAITH: To believe in God, there is the necessity of faith. (Heb 11:6) But without faith it is impossible to please Him, for he who comes to God must believe that He is, and that He is a rewarder of those who diligently seek Him. As finite human beings we should not expect to be able to comprehend an infinite God. (Rom 11:33-34) “Oh, the depth of the riches of the wisdom and knowledge of God! How unsearchable his judgments, and his paths beyond tracing out! ‘Who has known the mind of the Lord? Or who has been his counselor?’” If one is devoid of faith, God is able to dispense it as a gift so that one may believe without test-tube proof. (Eph 2:8) For by grace you have been saved through faith, and that not of yourselves; it is the gift of God.
FEELING: The book of Ecclesiastes would be a great book of the Bible for the agnostic to read and discern. This book chronicles king Solomon’s shift away from God and the emptiness it produced. Agnostics have personal feelings like the rest of us. Empty feelings may be the result of an empty philosophy. We can be so smart and yet be so unhappy.
Jesus’s answer to “doubting Thomas” was “. . . because you have seen Me, you have believed. Blessed are those who have not seen and yet have believed.” (John 20:29)