- Credulity to the point of gullibility
Believing in everything is stupid and dangerous. Believing "just in case" or accepting a claim as true by default and not requiring supporting evidence is foolish. Faith falls into this category.
- Voluntary, willful ignorance
Keeping yourself in the dark on purpose is a sin in my book. Knowledge is always a good thing. Sure, ignorance is bliss but it's also ignorant. I'd rather be happy I know (or don't know) something and know it. You should always be willing to learn and be willing to change your mind if you find out you don't have the right information.
- Letting fear prevent you from understanding reality
Being afraid of the truth because it hurts or is too scary to face can be reasons for committing the aforementioned sin. I might go as far as to say the main reasons for the existence of religion are to A) make the unknown less scary (by claiming it to already be known), and B) to provide a more palatable version of reality. Yes, the truth sometimes hurts. Knowing that your lost loved ones aren't waiting for you in some magical realm is sad. Knowing that you're going to die is scary. But replacing knowledge for a false reality because of fear doesn't change reality, and it only makes it that much harder to come to grips with. As one religious text says, the truth will set you free.
- Limiting the rights and freedoms of others in order to make them abide by your standards
The standards of your religion are up to you to follow -- don't push them onto others. This "sin" is probably the main cause for many atheists and freethinkers such as myself to speak out so fervently against religion. Almost on a daily basis in the United States, Christians are pushing to get their religious standards into the law of the land. (California's Prop8 is a current example.) Keep your God out of my government and I'll leave you to your delusions.
- Sacrificing the mental, emotional, and physical well-being of a child in deference to your religion
Forcing religion on kids is child abuse. A child can be told almost anything at a young enough age and believe every word of it. Not allowing them to learn or ask questions is tantamount to keeping them locked in the basement. And it goes much further than just the psychological trauma of telling them things like they'll go to hell: kids actually die because parents just pray instead of seeking medical attention. If you want to die for your beliefs then that's fine, but don't endanger anyone else's life -- especially a child's.
- Wasting your one and only life worrying about and working for an afterlife that somebody told you might exist
Not living your life to the fullest is something that I would consider sinful. Spending that life hoping for an afterlife is even worse. It's foolish to try to prepare for something that has not been demonstrated even one tiny bit. Sure it's okay to hope, but you can't waste your life -- the only one you know for sure you get -- on blind faith.
- Only doing good based on the sole purpose of receiving a reward or avoiding punishment
Doing good because God tells you, not for goodness sake. We nonbelievers can help people because it's the right thing to do. Humans are cooperative, social creatures. Together, we've made the world what it is today. We learn from each other, teach each other, and pull ourselves up from the pits of ignorance -- and we don't need a god to do it. If you truly think you need a god to be good, then please stop reading this blog and do whatever it takes to keep your theism!
To commit most of these sins requires a religious worldview, but for whatever the reason, ignoring reality for what it really is and trying to push your skewed view onto others is a transgression to humanity.