I put this into bullets so that it would be easier to critique individual premises. Logically, in order for an argument to be proven to be invalid, all you have to do is show how the premises don't follow to a conclusion, which can be done through showing how one of the premises are wrong.
- According to Calvinism, man is unable to come to salvation by his own power, and can only come to salvation through irresistible grace.
- If man is unable to come to salvation by his own power, then he can't help but sin (there is no middle ground between faith and sin).
- Therefore, according to Calvinism, man can't help but sin.
- Blame implies freedom, such that a person can only be blamed for what he's free to accept or reject. I.e., you can't blame a person for doing that which he can't help but do.
- Calvinism holds that the individual isn't free to accept or reject God except through irresistible grace.
- Therefore, Calvinism shouldn't place blame on sinners, given that blame implies a freedom to accept or reject God that isn't possible without irresistible grace.
- However, Calvinism does place blame on sinners; therefore Calvinism is logically inconsistent.
- Hold that individuals are free to reject grace, which would allow them to be blameworthy, given that blame implies freedom to accept or reject -- but here you don't have Calvinism.
- Hold that individuals are born in a state of innocence, not in sin, and that they're blameworthy in the sense of sinning first -- but here you have an unorthodox position that rejects original sin.
- Hold that theology doesn't need to be logically consistent -- but here you can believe anything about God given the lack of logic with exegesis.