I don't think that's really the message the author was trying to convey: "Read the life of a great scientist like Agassiz. Was he forever at the world’s beck a

I don't think that's really the message the author was trying to convey: "Read the life of a great scientist like Agassiz. Was he forever at the world’s beck and call? Not for a single day. To letters inviting him to write, or to lecture for money, he replied that he had no time for those things." The message seems to be more about using your time the way you want to use your time, and not the way others want you to use it. Want to work 20 hours a day? No problem - the author would encourage that as you're using the days you have as best you can to get where you want. Want to work 4 hours a day and spend the rest of the time with your family? Author encourages that too as long as you're providing them what they need. Basically: it's your time, not someone else's time to decide what you do with it.