Emerson presents knowledge as a form of power because understanding increases a person’s ability to judge, act and respond effectively. Knowledge can reveal opportunities, clarify causes and reduce dependence on guesswork or other people’s authority. In this sense, even information that appears abstract may eventually enlarge practical or intellectual capability.

Within Old Age, the statement fits Emerson’s wider argument that accumulated experience and understanding are important advantages of later life. Physical strength may diminish, but knowledge acquired over time can continue to provide judgement, perspective and influence. The quotation is deliberately broad and should not be read as claiming that every piece of information produces immediate control or success. Rather, Emerson treats knowledge as a resource that expands what a person can understand and potentially do.