Everybody is at least the things, what the were, what they are, and what they want to become. The quote suggests that a person should take the first step or an other step toward theri goal.
It's fairly common maxim. Sometimes it is said, the journey of a thousand steps begins with the first step. or If you don't have a dream, how will you have a dream come true? or Hide not your light under a bushel. or Get up and go before your get up and go went. "eBgin to be now what you will be hereafter" alludes to the fact that the decisions and actions we take now, in the present, are the foundation and spark of what we will be, and be doing in the future. It all begins with our thoughts and dreams. These typically motivate us to take action to reach a goal. Sometimes we consciously take action to realize a predetermined goal. This is what the line by William James is referring to. However, sometimes we take conscious