What is the ruling on atheism based on conviction in Islam, and will its adherent abide eternally in Hellfire?

Atheism is the denial of the existence of the Creator. An atheist is a disbeliever who will abide eternally in Hellfire, whether his atheism stems from conviction, imitation, or stubbornness. A disbeliever is not excused by claiming to be searching for the truth, because the proofs of God's existence and the truthfulness of Islam are clear to anyone who sincerely seeks them. Therefore, his claim that he strove and his striving led him to something else is mere obstinacy. God has condemned the deniers among the disbelievers in many verses, and the proofs of monotheism and prophethood are evident and abundant, so no one is excused by ignorance or heedlessness concerning them.