Discussions of technoscience are bringing to light that scientific journals feature very different knowledge claims. At one end of the spectrum, there is the scientific claim that a hypothesis needs to be reevaluated in light of new evidence. At the other end of the spectrum, there is the technoscientific claim that some new measure of control has been achieved in a laboratory. The latter claim has not received sufficient attention as of yet. In what sense is the achievement of control genuine knowledge in its own right; how is this knowledge acquired; and publicly validated? Notions of tacit or embodied knowledge, of knowledge by acquaintance, of engineering or thing knowledge, and reconstructions of ability or skill take us only part of the way towards answering such questions. The epistemology of technoscience needs to account for the acquisition and demonstration of a public knowledge of control that does not consist in the holding of propositions, even though it is usually communicated in writing: Technoscientific knowledge is, firstly, objective and public insofar as it is exhibited and documented. Secondly, it presupposes a specific context of technology and expertise. Thirdly, it is communicable, even where the achieved capability itself is not. Knowledge of control entails, fourthly, a knowledge of causal relationships, and it sediments itself, fifthly, as a habit of action in the sense proposed by Charles Sanders Peirce.