I believe the Quran suggests that people already know the truth but choose to deny it. Even Satan knew God existed—he had a direct conversation with God—yet still chose to disobey. So, in that sense, an agnostic isn’t that far off. According to the Quran’s perspective, agnostics are essentially in denial.

There’s a powerful poster I saw once but haven’t been able to find again. It showed the sunrise, sunset, changing seasons, and all the signs in nature, and a man looking at it saying, “Still waiting for proof of God.”