This comment responds to Kevin Warwick’s article on predictability and responsibility with respect to brain-machine interfaces (BMI) in action. It compares conventional responsibility for device use with the potential consequences of phenomenological human-machine integration which obscures the causal chain of an act. It explores two senses of “responsibility”: 1) when it is attributed to a person, suggesting the morally important way in which the person is a causal agent, and 2) when a person is accountable and, on the basis of fairness about rewards and sanctions, has a duty to act responsibly and accept liability. The comment suggests that, in the absence of absolute knowledge and predictability, we continue to engage in practical forms of reasoning about the responsibility for BMI-use in ways which are inclusive of uncertainties about the liability of persons versus devices and those who create them.