Negative results often conflate two fundamentally different scientific outcomes: evidence that a hypothesis is false, and insufficient evidence to decide. I argue that the latter, Unknown, can itself be a meaningful scientific result when we can characterize where and why the available evidence ceases to support an inference. Using traceroute geolocation as a worked example, I show how making this boundary explicit can prevent unsupported conclusions, make scarce validation more useful, and direct new measurement. Unknown is not a substitute for independent validation: internally consistent evidence can still be systematically wrong. But neither should Unknown be treated as failure. Sometimes establishing where our ability to tell True from False ends is itself the result.
This article grew out of an invited keynote at the first ACM SIGCOMM Workshop on Negative Results in Network Measurement (NetNeg 2026).