In the first part of this commentary I argue that a neurophenomenological analysis of color reveals additional asymmetries that preclude undetectable color transformations, without appealing to weak arguments based on Basic Color Categories (BCCs); that is, I suggest additional factors that must be included in “an empirically accurate model of color experience,” and which break the remaining asymmetries. In the second part I discuss the “isomorphism constraint” and the extent to which we may predict the subjective quality of experience from its neurological correlates. Protophenomena are discussed as a way of capturing in a relational structure all of qualitative experience except for the bare fact of subjectivity.

The claim that isomorphism in perceptual behaviour allows for differences in inner experience holds only if experience is taken to be an entity quite distinct from perceptual behaviour and only accidentally related to it. But this is not so. The two are internally related; experience as conceptualised being inherent to perception as a species of normative behaviour.

The concept of intrinsic aspects of color experience is flawed and functionalism remains plausible. The idea of spectrum inversion cannot survive in the context of a realistic conception of color.

Palmer's “isomorphism constraint” may be interpreted as a claim about (1) what can be known with certainty, or (2) what can be detected, or (3) what beliefs can be justified on the basis of a certain kind of scientific knowledge. I argue that his claim is valid if interpreted in one of the first two ways, but invalid if interpreted in the third way.

The controversial status of goluboi as a basic color term is discussed. Fuzzy logic alone cannot reliably attribute basic status to goluboi. Recent linguistic studies support a single basic blue category. Psychophysical data on color-space distances and color naming are currently ambiguous in this regard.

In restricting his analysis to the causal relations of functionalism, on the one hand, and the neurophysiological realizers of biology, on the other, Palmer has overlooked an alternative conception of the relationship between color experience and the brain – one that liberalizes the relation between mental phenomena and their physical implementation, without generating functionalism's counter-intuitive consequences. In this commentary we rely on Palmer's earlier work (especially from 1978) to tease out this alternative.

Palmer's principled distinction between first-person experience and scientific access is called into question. First, complete color transformations of experience and memory may be undetectable even from the first-person perspective. Second, transformations of (say) pain experiences seem to be intrinsically connected to certain effects, thus giving science access to these experiences, in principle. Evidence from pain research and emotional psychology indicates that further progress can be made.

Palmer demarcates the bounds of our understanding of color experience by symmetries in the color space. He claims that if there are symmetries, there can be functionally undetectable color transformations. However, even if there are symmetries, Palmer's support for the possibility of undetectable transformations assumes phenomenal internalism. Alternatively, phenomenal externalism eliminates Palmer's limit on our understanding of color experience.

In this commentary I point out that Palmer mislocates the source of the inverted spectrum, misrepresents the nature of colour science, and offers no reason for prefering one colour machine over another. I conclude nonetheless that talk about “colour machines” is a step in the right direction.

Palmer's color room argument is first contrasted with a different argument by Tim Maudlin against the sufficiency thesis of strong AI. This thesis turns out to be false and hence we need to determine the relevant supervenience base of phenomenal consciousness. That could be done by causal theories and intraindividual experiments. Finally, even if we cannot explain the intrinsic character of conscious states, we may be able to know what the experience of another person is like.

We can in fact obtain scientific information about the contents of consciousness by the methods of introspectionist psychology. An example comes from the author's work on the stroboscopic patterns and from the way psychedelic drugs alter color perception.

I defend the possibility of a functional account of the intrinsic qualities of sensory experience against the claim that functional characterization can only describe such qualities to the level of isomorphism of relational structures on those qualities. A form sensory holism might be true concerning the phenomenal, and this holism would account for some antifunctionalist intuition evoked by inverted spectrum and absent qualia arguments. Sensory holism is compatible with the correctness of functionalism about the phenomenal.

It is argued that given the task Palmer sets himself, there are no constraints on his colour experiences whatsoever.

The isomorphism constraint places plausible limits on the use of third-person evidence to explain color experience but poses no difficulty for functionalists; they themselves argue for just such limits. Palmer's absent qualia claim is supported by neither the Color Machine nor Color Room examples. The nature of color experience depends on relations external to the color space, as well as internal to it.

Palmer's main intuition pump, the “color machine,” greatly underestimates the complexity of a system isomorphic in color experience to humans. The neuroscientific picture of this complexity makes it clear that the brain actively produces our experiences by processes that science can investigate, thereby supporting functionalism and leaving no (color) room for a passive observer to witness subisomorphic experiential differences.

The originator of the notion of structural isomorphism was the philosopher Roy Wood Sellars. Many modern philosophers are unaware how this notion vitiates their attacks on the concept of an internal sensory presentation. His view that this allowed for corrective feedback undercuts Palmer's belief that there is a mapping of objects. The privacy of subjective experience is also shown not to be inviolable.

In this Response, I defend the notion of intrinsic qualities of experience, discuss the distinction between relational experience and relational structure, clarify the difference between narrow and broad interpretations of color experience, argue against externalist approaches to color experience, defend the concept of isomorphism as a limitation in understanding color experiences, examine critiques of the color machine and color room arguments, and counter objections to within-subject experiments based on memory limitations.

Following much work in linguistic theory, it is hypothesized that the language faculty has a modular structure and consists of two basic components, a lexicon of (structured) entries and a computational system of combinatorial operations to form larger linguistic expressions from lexical entries. This target article provides evidence for the dual nature of the language faculty by describing recent results of a multidisciplinary investigation of German inflection. We have examined: (1) its linguistic representation, focussing on noun plurals and verb inflection (participles), (2) processes involved in the way adults produce and comprehend inflected words, (3) brain potentials generated during the processing of inflected words, and (4) the way children acquire and use inflection. It will be shown that the evidence from all these sources converges and supports the distinction between lexical entries and combinatorial operations.

Our experimental results indicate that adults have access to two distinct processing routes, one accessing (irregularly) inflected entries from the mental lexicon and another involving morphological decomposition of (regularly) inflected words into stem+affix representations. These two processing routes correspond to the dual structure of the linguistic system. Results from event-related potentials confirm this linguistic distinction at the level of brain structures. In children's language, we have also found these two processes to be clearly dissociated; regular and irregular inflection are used under different circumstances, and the constraints under which children apply them are identical to those of the adult linguistic system.

Our findings will be explained in terms of a linguistic model that maintains the distinction between the lexicon and the computational system but replaces the traditional view of the lexicon as a simple list of idiosyncrasies with the notion of internally structured lexical representations.

We discuss other recent studies on the acquisition of the German plural that do not support the dual-mechanism model. The attested overgeneralizations are not by default only, nor completely random, but predictable from subregularities based on the grammatical gender and the phonology of the noun. In addition, the dual-mechanism model creates a number of problems for acquisition (theory) rather than solving existing ones.

Clahsen's claim that output forms of productive processes are never listed in the lexicon is a consequence of the rule/list fallacy, empirically incorrect, and not necessary for the hypothesis that the human language faculty has a dual structure, that is, a lexicon and a set of rules.