You can't directly, but you can often will yourelf to believe if you find the idea of god not existing to be too uncomfortable. You can't really choose your opinions, per se, as in your favorite color for instance, but you can 'choose' atheism by applying critical thinking to religion. Theists say we 'chose' to become atheists simply because we came to the conclusion that god doesn't exist. You can interfere with this discovery to a good extent by going
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John Adams Wrote:The Government of the United States of America is not, in any sense, founded on the Christian religion.