Arguments against thiesm

Argument from Parsimony
P1: The development of religion and human belief in God(s) are adequately explained by natural means
P2: The development of religion and human belief in God(s) are adequately explained by supernatural means
P3: Natural explanations require fewer assumptions in order to work
C: By Occam's Razor, belief in God(s) can be dismissed

Free will is incompatable with Christianity
P1: God creates all people
P2: God knows everything that will happen in the future
P3: God has the power to create all possible humans
C: It is impossible for a person to exist who has not had all of their choices decided by god at the moment of their creation by god

Weak epistemology of 'faith'
When confronted by the fact that it is impossible to reach the conclusion that god exists either logically or experimentally, many theists will say that faith is required and that if it is genuine, should lead you to the correct conclusion.

Now, when I look at Christian Fundies and Muslims, I see two groups of people who’s faith in their religion seems incredibly genuine. We are left with only a couple of options to make sense of this, either EVERYONE in one of those groups is a liar and does not have genuine faith, or at least some people in each group do, and genuine faith is not therefore not a consistent way to reach correct conclusions.

Proof:

P1: ∃x G(x) → c : x ∈ People
There exists a person such that Genuine Faith (G) implies belief in Christianity

P2: ∃x G(x) → m : x ∈ People
There exists a person that Genuine Faith (G) implies belief in Islam

P3: (c ∧ m) ≔ F
The proposition “Christianity and Islam” is defined as Falsum

C: ∃x G(x) → F : x ∈ People
There exists a person such that Genuine Faith (G) implies belief in Falsum

Arguments against athiesm

Kalām cosmological argument
P1: Whatever begins to exist has a cause of its existence.
P2: The universe began to exist.
C: Therefore, the universe has a cause of its existence.