A growing controversy at the interface of philosophy and cognitive science concerns the question of where cognition is located. In the paper “The Extended Mind” (1998), the book Supersizing the Mind (2008) and many other publications, Andy Clark contends that cognitive processes do not only occur in the head but also physically extend into the environment. In contrast and critical response to Clark, Adams/Aizawa (2008) and Rupert (forthcoming) hold that cognition is an entirely brain-bound affair. In the present thesis, I will argue that Clark’s extended cognition hypothesis as well as Adams/Aizawa’s and Rupert’s brain-bound accounts should be rejected because they lack plausibility and are cognitive-scientifically gratuitous. However, even though I dismiss Adams/Aizawa’s and Rupert’s specific brain-bound views, I will reach a conclusion similar to theirs: contra Clark, cognition remains an internal phenomenon.