In a recent paper, Schaefer et al. proposed to enhance autonomy via improving reasoning abilities through cognitive enhancement [1]. While initially their idea additionally seems to elegantly avoid objections against genetic enhancements based on the value of autonomy, we want to draw attention to several problems their approach poses. First, we will show that it is not at all clear that safe and meaningful methods to genetically or pharmaceutically enhance cognition will be feasible any time soon. Second, we want to (...) provide a deeper discussion of the role of cognition and reasoning abilities in philosophical concepts of autonomy, as discussed in the mentioned paper. In doing so, we wish to demonstrate that using reasoning abilities as the common denominator in different accounts of autonomy in the context of enhancement does not do justice to the highly complex interrelations between cognition, reasoning abilities and autonomy. Neither should this way of arguing be accepted as a basis to call for practical outcomes, such as funding research into e. g. genetic cognitive enhancements, if the examined concepts of autonomy are taken seriously. (shrink)