In Mossio & Taraborelli (2008) we challenged the assumption according to which the ecological and sensorimotor approaches are mere conceptual variations on the same enactive theme. We showed, on the contrary, that they endorse substantially different notions of an "action-dependent perceptual invariant" and we submitted that this distinction has interesting theoretical and empirical implications. This dissimilarity between ecological and sensorimotor theories stems, in our view, from a more fundamental divergence on the nature of perceptual information. Since Gibson's work, the ecological approach has adopted a fundamentally realist stance, according to which this information is "picked up", "revealed", "encountered" and "exploited" by the organism (as a range of affordances) but not "constituted" by the activity of the organism. In contrast, sensorimotor approaches take an explicit interactivist position, which sees the perceiver's motor activity as a determinant of perceptual information itself. Pascal & O'Regan (2008) suggest that our analysis of the relationship between ecological, sensorimotor and enactive theories would benefit from a further distinction. The original enactive approach (Varela et al. 1991; Maturana, 2002; Thompson, 2007), they argue, should not be lumped together with contemporary sensorimotor approaches to perception: whereas sensorimotor theories endorse an externalist view of perception, according to which "perception can only be understood as a form of interaction of the organism with the environment", the original enactive approach by Varela and collaborators would have strong "idealist underpinnings".