The real wisdom here lies in its subtle rejection of the either/or trap—the false choice between accepting your past as destiny or wasting energy on impossible revision. Lewis recognizes that most of us get stuck oscillating between these two poles, when the actual work is far more modest: acknowledging that your starting point is fixed while your trajectory remains entirely open. A person who spent twenty years in an unfulfilling career doesn't need to erase those decades to make the next twenty matter; the specific gravity of that earlier choice becomes irrelevant the moment they decide differently today. What makes this different from mere "it's never too late" cheerleading is its clear-eyed acceptance of loss—you genuinely cannot undo the beginning—paired with an almost mathematical precision about what *can* be changed: only the direction forward.