Connecting human minds to various technological devices and applications through brain-computer interfaces (BCIs) affords intriguingly novel ways for humans to engage and interact with the world. Not only do BCIs play an important role in restorative medicine, they are also increasingly used outside of medical or therapeutic contexts (e.g., gaming or mental state monitoring). A striking peculiarity of BCI technology is that the kind of actions it enables seems to differ from paradigmatic human actions, because, effects in the world are (...) brought about by devices such as robotic arms, prosthesis, or other machines, and their execution runs through a computer directed by brain signals. In contrast to usual forms of action, the sequence does not need to involve bodily or muscle movements at all. A motionless body, the epitome of inaction, might be acting. How do theories of action relate to such BCI-mediated forms of changing the world? We wish to explore this question through the lenses of three perspectives on agency: subjective experience of agency, philosophical action theory, and legal concepts of action. Our analysis pursues three aims: First, we shall discuss whether and which BCI-mediated events qualify as actions, according to the main concepts of action in philosophy and law. Secondly, en passant, we wish to highlight the ten most interesting novelties or peculiarities of BCI-mediated movements. Thirdly, we seek to explore whether these novel forms of movement may have consequences for concepts of agency. More concretely, we think that convincing assessments of BCI-movements require more fine-grained accounts of agency and a distinction between various forms of control during movements. In addition, we show that the disembodied nature of BCI-mediated events causes troubles for the standard legal account of actions as bodily movements. In an exchange with views from philosophy, we wish to propose that the law ought to reform its concept of action to include some, but not all, BCI-mediated events and sketch some of the wider implications this may have, especially for the venerable legal idea of the right to freedom of thought. In this regard, BCIs are an example of the way in which technological access to yet largely sealed-off domains of the person may necessitate adjusting normative boundaries between the personal and the social sphere. (shrink)