"I Don't Know Why" by Starship is a love song that describes the feeling of being with someone who makes everything feel magical. The lyrics are filled with imagery of warm sunrises, crossed boundaries, and open doors. The singer feels like a child when they're with their lover and wants to hold onto that feeling forever. Overall, the song is about the power of love to transport us to a different time and place. It's a celebration of the way that being in love can make us feel young and carefree, even if we don't fully understand why.