Answer: I do not know if this is a multiple-choice question or not, but I would contend that it is because nature cannot betray or reject him, as humans do—since he is an illegitimate son—and he is requesting her protection.
Explanation: Just to elaborate a little on the answer, it can be added that Edmund is an illegitimate son, and, as such, he has been denied the same rights as his half-brother, Edgar. This bothers him tremendously, and he is ready to rebel. In these initial lines of his soliloquy he is expressing his trust in the goddess nature, the only one that, to his eyes, is impartial and cannot deprive him of his dignity and his humanity. Experience has proven to him that he cannot trust men, or anything that is touched or devised by them, since they have systematically rejected him for being an illegitimate son, and he is ready to resort to the gods in order to receive protection and fulfill his plan of seizing his brother's lands.
