Having constructed a new theory of causation that culminated with the introduction of the Central Thesis in chapter 12, we are in position to offer a promising new account of what human consciousness is and what causal relationships it shares with the physical. Recall the definition of the Central Thesis: According to the Central Thesis, the existence of subjects that experience phenomenal properties is coextensive with the existence of naturally individuated causal systems (as discussed in chapters 9-11). This thesis thus creates a rudimentary kind of bridging law between causal systems and experiencing subjects: Phenomenally speaking, all natural individuals are subjects of experience, and causally speaking, all subjects of experience are natural individuals. If this thesis is right, then whenever we can ascertain the existence of a natural individual, we can infer the existence of a corresponding experiencing subject; likewise, whenever we can ascertain the existence of an experiencing subject, we can deduce the existence of a corresponding natural individual. Of course, one can readily ascertain the existence of an experiencing subject in one's own first person case, and one can reasonably judge other cognitively normal humans to be experiencing subjects as well. Thus, an application of the Central Thesis predicts that some causal system in the normally functioning human brain is a natural individual whose existence corresponds to the bounded qualitative field that constitutes a human's first person subjective experience. This prediction is stated with more detail and rigor in the Consciousness Hypothesis: With the Consciousness Hypothesis in place, we are ready to reap the payoff from our work on causation. We have created a new metaphysical context within which to place human consciousness, and this new place for consciousness will allow us to redress the many conceptual puzzles, mysteries, and paradoxes that swirl around it and make it so profoundly problematic. In particular, the key features of our revised causal picture of the world that will pay big dividends are receptivity and the notion of phenomenal/experiential carriers. The introduction of receptivity into the causal story provides new layers of causal structure with which we can explain some of consciousness's more puzzling structural aspects and reconcile them with the apparently incompatible physical structure of the brain. The casting of phenomenal and experiential properties as carriers for effective and receptive properties will allow us to coherently address the fundamental mystery of why a physical brain is even associated with an experiencing subject in the first place, and will furthermore allow us to talk about the nature of the causal relationship between the two without lapsing into epiphenomenalism or interactionism. In part I of this book, we explored some of the problematic aspects of consciousness in detail. We argued that consciousness cannot be satisfactorily accounted for by physicalism, and that rejecting physicalism is likely to lead to some form of panexperientialism. We went on to examine a number of conceptual puzzles and paradoxes about consciousness and its relationship to the physical, including a puzzle about the unity of consciousness, the paradoxical simultaneity of the subjective instant, the knowledge paradox, the apparent superfluity of consciousness, the grain problem, and the boundary problem. In this chapter, we will revisit each of these tensions and puzzles from the point of view of the Consciousness Hypothesis. With our new metaphysical framework in tow, we will be able to resolve some of these seemingly intractable problems outright and garner significant new insights into others. In fact, not only will be able to melt away many of the fundamental mysteries surrounding consciousness, but we will also be able to comprehend why those particular kinds of mysteries have arisen at all; as Rosenberg puts it, "The end result is the striking discovery that the fundamental carriers of effective and receptive causation would have predictable properties that parallel the troublesome properties of consciousness" (p. 253). In sum, we will be able to weave once hopelessly fractured and disjoint concepts about consciousness and the physical into a single, neat, coherent tapestry. By demonstrating the new explanitory powers granted to us by the Consciousness Hypothesis, we will have shown it to be a fruitful thoeretical tool in redressing and unifying our concepts about the subjective and objective aspects of nature, and this fruitfulness will in turn lend further support and credibility to the Liberal Naturalist paradigm we have thus far outlined. (Rosenberg names this overarching framework-- including the Theory of Causal Significance, the Carrier Theory of Causation, the Central Thesis and the Consciousness Hypothesis-- the Theory of Natural Individuals. For convenience, I will refer to the Theory of Natural Individuals as "TNI" for the remainder of this summary.) A High Level Sketch It is worth taking a moment to reflect on the kind of metaphysical picture that the Consciousness Hypothesis paints. A useful way of thinking about the Consciousness Hypothesis is in terms of internal and external points of view. The Consciousness Hypothesis roughly states that the subjective, conscious mind and some subsystem of the objective, physical brain are not seperate entities, but rather are the same thing as seen from two different vantage points. Roughly, the conscious mind is what some portion of the brain looks like "from the inside," and likewise, some portion of the brain is what the conscious mind looks like "from the outside." The internal point of view is privileged in the sense that it allows direct knowledge of the intrinsic natures of an individual's carriers. Unfortunately, the only way to 'see' a natural individual from the inside is to actually be that individual, since phenomenal properties can only be experienced by the single experiencing subject (the single instance of receptivity) within which they are bound. For this reason, the nature of an individual's intrinsic carriers is lost to the external view. From the outside, all we can see is the structured system of abstract relationships into which an individual's phenomenal properties enter. These abstract relationships, of course, are nothing but the effective properties bound within the individual, and effective properties are exactly the objects of study for the sciences. Thus, much of the individual's substantial inner being is opaque to third person investigation. Although it can teach us much, the external, third person view of an individual provides us an impoverished, abstract, indirect, and ultimately incomplete way of understanding it. (For a discussion on why effective properties can be observed from the third person, see the section titled 'effective properties' in chapter 9. This discussion should make it clear why receptivity and carriers are not likewise amenable to third person investigation.) Avoiding the Failures of Physicalism There are a number of arguments against the thesis that consciousness supervenes upon the physical, including the logical possibility of inverted spectra, the logical possibility of zombies, the epistemic asymmetry between facts about phenomenal consciousness and other facts, the knowledge argument, and the absence of analysis. Each of these arguments points to a systematic, in principle failure of explanation of experiential facts using only physical facts. Turning these arguments against TNI serves as a healthy check to ensure that TNI is not plagued by the same fundamental explanitory shortcomings of physicalism, with respect to phenomenal consciousness. The absence of analysis argument and the knowledge argument essentially boil down to the objection that phenomenal consciousness cannot be fully analyzed into the schematic structural and functional facts available to physicalism. This objection is not at odds with TNI, since the phenomenal and experiential carriers of the world's effective and receptive properties are explicitly understood to evade complete systematic analysis. In the terminology of chapter 12, these carriers are extrinsic within all schematic systems, and so cannot be fully characterized by merely schematic facts. So TNI's ontological building blocks are not limited to structural and functional facts, but also include fundamental intrinsic facts-- and indeed, these intrinsic facts figure prominently into the TNI account of consciousness. The argument from epistemic asymmetry observes that our only reason for believing in consciousness in the first place is our private, subjective experiences rather than the public, external facts available from a physicalist perspective. Since third person facts give us no reason to believe in consciousness, and since physicalism only endows us with third person facts, physicalism seems to overlook a crucial piece of evidence regarding consciousness. However, evidence from subjective experience is not neglected by TNI, but rather plays a significant role in its construction. Recall that when we argued in chapter 12 that phenomenal and experiential properties could be pressed into service as the world's fundamental, intrinsic carriers, we justified the argument by analogical appeal to features of consciousness that can only be observed from the first person. The argument from the logical possibility of zombies asserts that physicalism fails because a complete physicalist account of the world is logically consistent with the absence of phenomenal consciousness. The zombie argument fails against TNI because phenomenal consciousness is built into it from the ground floor by the Central Thesis (and, by extension, the Consciousness Hypothesis). A complete TNI account of the world will explicitly include facts about phenomenal and experiential carriers, and thus will not be logically consistent with the absence of phenomenal consciousness. The inverted spectrum argument claims that the physical facts about our brains are logically consistent with an inversion of the qualitative color spectrums we experience in the first person. If it is true that physical facts do not logically fix phenomenal facts, then any attempt at an explanitory reduction of phenomenal facts to physical facts is undermined. However, TNI does not attempt to reduce phenomenal facts to physical facts, but rather explains physical facts in terms of the internal contrasts that obtain among fundamental phenomenal facts. So, at worst, the logical possibility of inverted spectra entails that diverse sets of phenomenal facts might realize the same set of physical facts. This presents possible epistemological dangers to TNI in trying to deduce phenomenal facts from physical facts, but does not present grave metaphysical problems as it does to physicalism. The arguments against physicalism all fail to gain traction against TNI. Physicalism runs into difficulties trying to explain phenomenal consciousness because it casts only schematic, third person facts as the world's fundamental building blocks, and then tries to reduce the apparently intrinsic properties of phenomenal consciousness to these schematic facts. The arguments against physicalism seem to be variations on the theme that you can't derive intrinsic facts from extrinsic ones. TNI evades this conceptual difficulty by turning the physicalist approach on its head. Where physicalism takes schematic facts to be fundamental and tries to explain facts about consciousness in terms of such schematic facts, TNI explicitly acknowledges the intrinsic facts about phenomenal and experiential carriers to be the most basic components of the world's ontological tool kit, and seeks to explain the world's schematic causal facts in terms of the inherent relationships that hold among these carriers. While physicalsim seems to lack an appropriate metaphysical account of how it could be that intrinsic or phenomenal facts can be grounded upon schematic facts, TNI features a plausible analysis by which the intrinsic properties of the carriers can necessarily determine the various extrinsic relationships that hold among them (see chapter 12).