Before a court, an eyewitness swears to what has been seen. “I swear I saw this!” If necessary under oath, it’s always a statement of perception in the service of truth. In a certain sense a kind of modern magic formula that reproduces the cosmology of the seers and the sworn and—that’s why we use the world cosmology—is never free of human inventiveness and perspectives. But machines and apparatuses, in contrast! Technology reproduces the visual and the audible affording to verifiable, repeatable, and adaptable techniques, analyzing material compounds, dating and cataloguing material. Unmistakably neutral, this witness. When in doubt for the apparatus? What if we look behind the work process in laboratories, institutions, computer technologies, or financial mechanisms? Which oath is sworn here? Insights into the collections of the International Court for the Former Yugoslavia, the functioning of lie detectors or sight systems, attempts to rethink eyewitnessing in the Anthropocene.