Actually there is a reason to reject the supernatural. A supernatural explanation can be invoked to explain anything and thus has no content. Water freezes because Poseidon wants it to; ice melts because Poseidon wants it to. These putative explanations are rejected (in scientific inquiry) because they allow no predictions at all. The assumption of supernatural intervention implys the inability to predict anything.
Actually there is a [fundamental] reason to reject the supernatural. A supernatural explanation can be invoked to explain anything and thus has no content. Water freezes because Poseidon wants it to; ice melts because Poseidon wants it to. These putative explanations are rejected (in scientific inquiry) because they allow no predictions at all. The assumption of supernatural intervention implies the inability to predict anything.