We review evidence for multifaceted functional specialization of somatosensory information processing, both within and outside classical somatosensory cortex. We argue that the nature of such specialization has not yet been clarified adequately to regard the proposed action/perception dichotomy as being established. However, we believe this is a good working hypothesis that can motivate further work.

Merker's approach allows the formulation of an evolutionary view of consciousness that abandons a dependence on structural homology – in this case, the presence of a cerebral cortex – in favor of functional concordance. In contrast to Merker, though, I maintain that the emergence of complex, dynamic interactions, such as those which occur between thalamus and cortex, was central to the appearance of consciousness.

Assuming our understanding of the brain continues to advance, we will at some point have a computational theory of how access consciousness works. Block's supposed additional kind of consciousness will not appear in this theory, and continued belief in it will be difficult to sustain. Appeals to “what it's like” to experience such-and-such will carry little weight when we cannot locate a subject for whom it might be like something.

Can we ever experimentally disentangle phenomenal consciousness from the cognitive accessibility inherent to conscious reports? In this commentary, we suggest that (1) Block's notion of phenomenal consciousness remains intractably entangled with the need to obtain subjective reports about it; and (2) many experimental paradigms suggest that the intuitive notion of a rich but non-reportable phenomenal world is, to a large extent illusory – in a sense that requires clarification.

“Decortication” does not distinguish between removing all cerebral cortex, including three-layered allocortex or just six-layered neocortex. Functional decortication, by spreading depression, reversibly suppresses only neocortex, leaving minimal intentionality. Removal of all forebrain structures except a hypothalamic “island” blocks all intentional behaviors, leaving only tropisms. To what extent do Merker's examples retain allocortex, and how might such residues affect his interpretations?

Neonatal behavioral data support the argument that multiple relations exist between vision and touch. Looking at an object triggers the motion of a neonate's arm and hand towards it. A textured surface that is seen can be recognized tactilely, but not a volumetric shaped object in cross-modal transfer tasks. These data are supported by adult neuroimaging data.

We examine and reject the claim that the past-directed aspect of mental time travel (episodic memory) is unique to humans. Recent work in our laboratory with rats has demonstrated behaviours that resemble “remember, know” judgements about past occasions. Similar to human episodic memory, we can also demonstrate a dissociation in the neural basis of recollection and familiarity in nonhumans.

Merker's fine article opens a new view of brain function consistent with current developments in robotics, heuristics, and fuzzy logic. A reciprocal, tripartite organization of input/motivation/output in the midbrain can accomplish the practical tasks of a brain. A bold move places consciousness in the midbrain, raising profound questions about the practical nature of consciousness.

Our commentary addresses two issues that are not developed enough in the target article. First, the model does not clearly address the distinction among external objects, external body parts, and internal bodies. Second, the authors could have discussed further the role of body schema with regard to its dynamic character, and its role in perspective and in imitation.

The role of time in episodic memory and mental time travel is considered in light of findings on humans' temporal memory and anticipation. Time is not integral or uniform in memory for the past or anticipation of the future. The commonalities of episodic memory and anticipation require further study.

The target article appeals to recent empirical data to support the idea that there is more to phenomenality than is available to access consciousness. However, this claim is based on an unwarranted assumption, namely, that some kind of cortical processing must be phenomenal. The article also considerably weakens Block's original distinction between a truly nonfunctional phenomenal consciousness and a functional access consciousness. The new form of phenomenal consciousness seems to be a poor-man's cognitive access.

Block shows that we can consciously see a scene without being able to identify all the individual items in it. But in itself this fails to drive a wedge between phenomenology and access. Once we distinguish scene phenomenology from item phenomenology, the link between phenomenology and access is restored.

Mental time travel is a principled, but a narrow and computationally limiting, implementation of foresight. Future events can be predicted with sufficient specificity without having to have episodic memory of specific past events. Bayesian estimation theory provides a framework by which one can make predictions about specific future events by combining information about various generic patterns in the past experience.

The observation that an animal's behavior is largely unaltered even after profound modifications of sizeable brain portions, suggests a large flexibility in the relationships between species-specific brain structures and species-specific behavior. In this perspective, a fascinating example is given by the comparison of jumping spiders and felids, where similar predatory behaviors are achieved with totally different brain substrates.

A general shortcoming of the localist, decompositional, approach to neuroscientific explanation that the target article exemplifies, is that it is incomplete unless supplemented with an account of how the hypothesized subsystems integrate in the normal case. Besides, a number of studies that show that object recognition is proprioception dependent and that cutaneous information affects motor performance make the existence of the proposed subsystems doubtful.

Merker's insightful broad review fertilely recasts the mind/brain issue, but the phenomenological appeals require additional considerations of behavioral and neural flexibility. Motor equivalences and perceptual constancies may be cortical contributions to a “robotic” tectal orientation mechanism. Intermediate “third layers” of associative neural networks, each with a few diffusely summing convergence-divergence modules, may be the economical expedient by which evolution has extended the limited unity-in-diversity of sensorimotor coordination to perception, action, thinking, and memory.

The model presented in the target article includes feature processing and higher representations. I argue, based on neuropsychological evidence, that spatial representations are also involved in perceptual awareness of somatosensory events. Second, there is an asymmetry, with a right-hemisphere–based bilateral representation of the body. Third, the specific aspect of bodily awareness concerning motor function monitoring involves a network that includes the premotor cortex.

The overlap of representations of past and future is not a completely new idea. Suddendorf & Corballis (S&C) usefully discuss the problems of testing the existence of such representations. Our taxonomy of memory differs from theirs, emphasizing the late evolutionary emergence of notions of time in memory.

One can distinguish among perceptual states that have been accessed by working memory, states that are accessible, and states that are inaccessible. Block compellingly argues that phenomenology outstrips access but wrongly implies that phenomenology outstrips accessibility. There is a subjective difference between Sperling cases and inattentional blindness, which suggests that phenomenology occurs under conditions of accessibility, and not inaccessibility.

Merker makes a strong case for the upper brain stem as being the neural home of primary or phenomenal consciousness. Though less emphasized, he makes an equally strong and empirically supported argument for the critical role of the mesodiencephalon in basic emotion processes. His evidence and argument on the functions of brainstem systems in primary consciousness and basic emotion processes present a strong challenge to prevailing assumptions about the primacy of cognition in emotion-cognition-behavior relations.