Emerson distinguishes between two entirely different failures here—the paralysis of dreamlessness versus the incompleteness of half-hearted effort—suggesting that ambition and work aren't redundant virtues but complementary ones that guard against separate pitfalls. A person might possess tremendous work ethic yet accomplish nothing meaningful simply because they lack any direction or hunger, while another might dream grandly but peter out before crossing the finish line. Consider the amateur writer who outlines a novel, begins three chapters with genuine passion, then abandons it because the initial fervor fades and sustained discipline never takes root. The quote's quiet genius lies in naming both the empty starting line and the cluttered path littered with unfinished things as evidence of incompleteness.