In this volume, based on his 1994 Jean Nicod lectures, Dretske continues the campaign begun in Explaining Behavior (Cambridge, MA: MIT Press, 1989), in which he accounted for the propositional attitudes (esp., belief and desire) in terms of the Representational Thesis. Turning to the area of the battlefield "where progress is most difficult"--namely, the topic of the quality of perceptual experience or "qualia"--Dretske now seeks to establish the plausibility of his thesis "for sensing affairs, for the phenomenal or qualitative aspects of our mental life." (pp. xiv-xv)

Dretske devotes the first four chapters to an elaboration of his positive thesis: that representational naturalism can "provide satisfying explanations of a variety of otherwise baffling phenomena--intentionality, self-knowledge, subjectivity, the possibility of qualia-inversion, the sensation-cognition distinction," etc. (p. 123) He employs an impressive arsenal of philosophical weaponry, including distinctions between systemic and acquired representations, sense and reference, vehicle and content, representation and meta-representation, conscious beings vs. conscious states, vertical (idealist) vs. horizontal (realist) theories of consciousness, etc--and a generous assortment of examples from the plant and animal kingdoms, as well as inanimate objects (e.g., thermostats and speedometers).

The careful reader of the challenging material in these chapters will be rewarded by such insights as: (1) Introspection "is not a process by which one looks inward[, but] an instance of displaced perception--knowledge of internal (mental) facts via an awareness of external (physical) facts." (pp. 40-41) (2) Qualia are "phenomenal properties--those properties that...an object is sensuously represented [i.e., by the organism's sensory system] as having." (p. 73) and (3) "Conscious mental states--experiences, in particular--are states that we are conscious with, not states we are conscious of." (p. 101)

The most powerful opposition to Dretske's theory comes from those convinced that "even if thought, belief, and judgment can be understood as internal representation of external affairs, sensation, experience, and feelings cannot[, that the latter] have a phenomenal, what-is-it-like, quality that defies representational... treatment." (pp. xv-xvi) Chapter 5 addresses this skepticism, which Dretske reduces to three variations on the "Internalist Intuition" that "experience cannot be externally constituted." (p. 149) It is important to bear in mind that "external" for Dretske includes bodily states. The plausibility of his case rests considerably on the extent to which he and others succeed in elucidating the essentially external nature of the objects of proprioceptive awareness.

(1) In answer to "the argument from self-knowledge," Dretske argues that one gets "privileged information about the character of one's own experiences not by looking inward," by experiencing one's experience, but by simply having the experience, "usually an experience of external objects [which] carries all the information one needs to know what the experience is like." (p. 149) Surely, this will not satisfy those who want an explanation for the peculiar aura or tang that characterizes experience, the fact that, as Antonio R. D'Amaso puts it, "when you see, you do not just see: you feel you are seeing something with your eyes." ("The Body-Minded Brain," in Descartes' Error, New York: Grosset/Putnam, 1994, p. 232. Also see Jerome Kagan, "Internal Tone," in Galen's Prophecy, New York: BasicBooks, 1994, pp. 285-90.) But Dretske covers himself by deferring to a later date the consideration of proprioceptive awareness of bodily states and processes, the most likely candidate for the "what-is-it-like" quality accompanying experience. This, too, it appears, could easily be dealt with by Dretske's explanatory machinery.

(2) Dretske uses a Putnamesque thought-experiment involving Fred and Twin-Fred to show how internalism results in contradiction when it "conceives of experience --in act-object terms--as the mind's awareness of internal objects or qualities," an idealist fallacy that confuses what we experience with our experience of it." (p. 149) Unfortunately, Dretske accepts uncritically the notion that people with different experiences could also be physically indistinguishable. This presupposes a counterfactual, pristine process of awareness having no physical effects in the conscious organism, with all the essential differences between two experiences being "out there," none within the organism itself. The problem here is Dretske's failure to observe his own stricture that internal physical states are to be considered "external." These very same states may well play a vital role in constituting the quality of experience. Had Dretske consistently applied his own guideline, he would have realized that once Fred and Twin-Fred are exposed to different stimuli, they will no longer be physically identical, which collapses his dubious Twin-Earth argument against the Internalists, while his broader anti-Internalist tenet--that experience is externally constituted--survives intact.

(3) Dretske's third line of attack against Internalism, the issue of "the causal efficacy of the mental" (introducing Fred's and Twin-Fred's best friends, Dog and Twin-Dog!), suffers from the same flaw as the second, though here he makes a decisive point: in "explaining a system's behavior, we are often looking, not inside for the physical cause (C) of external change (E)...but outside for the events and circumstances that shaped internal structures...the structuring, not triggering [in Aristotelian terms: "formal," not "efficient"] causes of behavior--the cause, not of E, but of C's causing E." (p. 159) That is, an organism's being conscious of this (rather than that) object or event determines that this (not that) will be among the reasons why it takes one action rather than another.

At one point, Dretske explains a less ambitious tactic by saying, "I'm trying to win a battle, not the war." (p. 127) This may seem overly modest, considering how effectively (despite noted lapses) he has prosecuted the current campaign. But the real Battle of the Bulge lies ahead for Dretske and the Externalists: the issue of proprioception and self-awareness.