Though you should pound the fool to bits with the pestle, amid the grits in a mortar, his folly would not go out of him.
As to the antitheists, materialists, secularists, empiricists, humanists and the like out there; they are actually correct in their basic assertion that there is no god, since they have reified for themselves an anthropomorphic "sky-daddy" (as they like to call it), that is nothing at all like God. It is the old straw man fallacy, but people are falling for it in droves.
All of their ensuing arguments, regardless of their feigned intelligence, cleverness, logic, or rationality, are entirely false because they argue to deny the existence of a fabricated thing that by design, doesn't actually exist. They have built themselves a god in their own image and that god must conform to their self-limiting world view or be rejected as false.
... Let him come down from the cross now, and we will believe in him..
It is futile to converse with them. They will not listen. Their minds are dark and their hearts are hard. If you were to tell them of the existence of birds, they would insist that you must show them proof by flipping over rocks. They would not lift up their eyes to the sky where you are pointing.
"Do not give what is holy to dogs, or throw your pearls before swine, lest they trample them underfoot, and turn and tear you to pieces.
More often than not, God deniers will try to defend their position by pointing to associates who hold some sort of academic credential in an effort to assert their correctness (appeal to authority fallacy). Often they will claim that by holding to the same idea as some famous or popular intellectuals that they therefore are intellectually superior to you and therefore their position is correct (spotlight fallacy).
Often an expert in one field of endeavor will say that since they cannot prove god exists within their area of expertise, god does not exist. Recently, noted evolutionary biologists have flaunted their credentials and used their platforms to argue this way. It's a form of spotlight fallacy in that the person, being an "expert" in one field is presented simply as an "expert" while disregarding the fact that they may have little, or no expertise in the actual field being discussed. An expert in X may be an imbecile in Y.
Frequently, they will point to the failings of persons (poisoning the well fallacy), or groups (guilt by asociation fallacy) who hold to the truth of God, or they will cite increasing numbers of people that agree with them (bandwagon fallacy) or (appeal to popularity fallacy), or they will screech vulgarities and hurl insults (ad hominem fallacy) or (personal attack fallacy), or simply resort to making a bunch of noise to drown out the opposing view.
Sometimes the empiricist will claim that the burden of proof rests on those who know God, to demonstrate that he exists within their frame of thinking. They assert that, since logically you cannot prove a negative (ie the non-existence of a thing), his existence must therefore be proven to them. That is a burden of proof fallacy, as they are trying to force proofs of God that fit into their (incorrect) idea of what god is.
Some may gratuitously say that belief in God is OK for you and me, but it is irrelevant for them (relativist fallacy), and some will try to move the discussion away from the core issue of God's reality to a similar related issue (red herring fallacy).
You can see that they use fallacies almost exclusively. (They sometimes use sophistry too.) They have to do so because error is indefensible. They don't seek truth, they seek only the illusion of a victory in the debate.
For everyone who does wicked things hates the light and does not come toward the light, so that his works might not be exposed.
The darkness of error is where they are, and familiarity with an environment gives a person a (false) sense of comfort regardless of the conditions of that environment. That is why the abused keep returning to their homes. It is futile to waste time in useless debate with them. Their ears are closed to truth and their eyes are shut to the light.
He said to them, "This kind can only come out through prayer."
Praying for them is far more efficacious than debating them.
No one can come to me unless the Father who sent me draw him, and I will raise him on the last day.
With prayer, the Father may draw them to the light. Without it they are lost.
"Pray, pray very much, and make sacrifices for sinners; for many souls go to hell, because there are none to sacrifice themselves and pray for them."
- Our Blessed Mother Mary - Fatima, Portugal - August 13, 1917
"We do not pray to convince God to act; our prayer for others is actually God’s way of permitting us to share in the good that He wants to give to them."
And just for fun, here's a little insult for the injured.
"...the principles of Darwinism cannot even be articulated without simultaneously transcending them. Or, once articulated, they falsify themselves..."