I can not 'make my mark' for all time - those concepts are mutually exclusive. 'Lasting effect' is a self-contradictory term. Meaning does not exist in the future and neither do I. Nothing will have meaning 'ultimately.' Nothing will even mean tomorrow what it did today. Meaning changes with the context. My meaningfulness is here. It is enough that I am of value to someone today. It is enough that I make a difference now.