Satan was the mastermind behind the rebellion. By cunningly deceiving Eve, and using her to influence Adam, who was not deceived, he was able to challenge God in a way that he knew God would have to address. Basically, their disobedience stated that they didn't want to follow God's commands and wanted to decide matters for themselves, so he let them make that choice. The Bible clearly tells us that Adam was not deceived, so he knew exactly what he was doing and what the consequences would be and he did it anyway.