This quote is often attributed to Ralph Waldo Emerson. However, it seems to have actually appeared in a 90’s Nike ad by Janet Champ and Charlotte Moore. It’s partly based on the idea of self-fulfilling prophecy. This is the notion that we will try to make our beliefs come true in order to make our perceptions match with reality.
This can and often does happen–Sometimes subconsciously. The worst part is when our subconscious belief about who we are and who we want to be is negative. This results in a negative affect on who we are and who we become.
This quote also goes beyond the idea of self-fulfilling prophecy. It also means that we cannot be something we haven’t made the decision to be in the first place. An athlete doesn’t become an athlete without deciding to be an athlete. A business owner doesn’t become a business owner without deciding to be a business owner. And an astronaut doesn’t become an astronaut without deciding to be an astronaut.
So consider the person you’ve consciously or subconsciously decided to be. If you’ve decided and you know it with unquestionable certainty, good. You’ve already achieved a very crucial step in becoming that person. If you haven’t decided, you might want to begin pondering.