Having realized he was getting dragged down by all the clutter in his life, Imagine Dragons frontman Dan Reynolds sought therapy. This Smoke + Mirrors track was inspired by his new outlook after getting the help he needed. "It's actually a love song to my wife," he told The Illinois Entertainer. "But it's really more than that, more than that for me. The chorus of it says 'Do you know you're all I know?,' which is a really simple phrase. But there's so much power in that phrase, because I feel like, at the end of the day, I started everything over in my life, my spirituality, everything. So I just wiped it clean."
"So the first thing that comes to mind when it's all clean and there's nothing there is, I know that I love my wife, and I know that she's my best friend, and I know that I love my little girl," he continued. "Those are the things that I know, and that, to me, was the resolution of the album. The resolution is that I don't know the answers. I don't know which religion is right – I don't know that stuff. But what I do know is, I love my wife, I love my kid, and I want to be a good person, someone honest. The rest? I have no idea!"