13. The voluntary inhibition of voluntary actions seems to be mostly determined by unconscious events in the anterior median cortex. See M. Brass & P. Haggard, «To Do or Not To Do: The Neural Signature of SelfControl,» J. Neurosci. 27:9141–9145. (2007).

14. See T. Metzinger, «The Forbidden Fruit Intuition,» The Edge Annual Question-2006: What Is Your Dangerous Idea? www.edge.org/q2006/ q06_7.htmlfflmetzinger. Reprinted in J. Brockman, ed., What Is Your Dangerous Idea? Todays's Leading Thinkers on the Unthinkable (New York: HarperPerennial, 2007), 153–155.

15. It would not be a new thought in the history of philosophy. Vasubandhu, a fourth-century Buddhist teacher and one of the most important figures in the development of Mahayana Buddhism in India, reports: Buddha has spoken thus: 'O, Brethren! actions do exist, and also their consequences (merit and demerit), but the person that acts does not. There is no one to cast away this set of elements and no one to assume a new set of them. (There exists no individual), it is only a conventional name given to (a set) of elements.' Appendix to the VIIIth chapter of Vasubandhu's Abhidarmakoga, § 9: 100.b.7; quoted after T. Stcherbatsky, «Th Soul Thory of the Buddhists,» Bull. Acad. Sci. Russ. 845 (1919).

CHAPTER 5

1. The second question, of course, is the one Descartes asked in the first Meditation, when he realized that everything he had ever believed to be certain-including his impression of sitting by the fire in his winter coat and closely inspecting the piece of paper in his hands-could equally well have occurred in a dream. What makes the problem of dream skepticism so intractable is that even in a «best-case scenario» of sensory perception, there is apparently no reliable, fool-proof method of distinguishing wakefulness and dreaming. According to dream skepticism, literally all of our experiences of waking life could be nothing more than a dream, and we are unable, even in principle, ever to decide this question with certainty. For a detailed discussion of the problem of dream skepticism, see, for instance, Barry Stroud, The Significance of Philosophical Scepticism (New York: Oxford University Press, 1984). For the status of the phenomenal and the epistemic subject in the dream state, see J. Windt & T. Metzinger, «The Philosophy of Dreaming and Self-Consciousness: What Happens to the Experiential Subject During the Dream State?» in Patrick McNamara & Deirdre Barrett, eds., The New Science of Dreaming (Westport, CT: Praeger, 2007). See http://eprints.assc.caltech.edu/200/01/Dreams.pdf.

2. See J. A. Hobson et al., «Dreaming and the Brain: Toward a Cognitive Neuroscience of Conscious States,» Behavioral and Brain Sci. 23:793–842 (2000); and Antti Revonsuo, Inner Presence: Consciousness as a Biological Phenomenon (Cambridge, MA: MIT Press, 2006).

3. Helen Keller, The World I Live In (New York: New York Review Books, 2003).

4. H. Bertolo et al., «Visual Dream Content, Graphical Representation and EEG Alpha Activity in Congenitally Blind Subjects,» Cog. Brain Res. 15:277 284 (2003).

5. See C. H. Schenck, «Violent Moving Nightmares,» www.parasomniasrbd.com/; E. J. Olson et al., «Rapid Eye Movement Sleep Behaviour Disorder: Demographic, Clinical, and Laboratory Findings in 93 Cases,» Brain 123:331339 (2000); and C. H. Adler & M. J. Thorpy, «Sleep Issues in Parkinson's Disease,» Neurology 64 (suppl. 3):12–20 (2005).

6. See Hobson et al., «Dreaming and the Brain» (2000) for details.

7. F. van Eeden, «A Study of Dreams,» Proc. Soc. Psychical Res. 26:431–461 (1913).

8. Oliver Fox, Astral Projection (New Hyde Park, NY: University Books, 1962). Also quoted in S. LaBerge & J. Gackenbach, «Lucid Dreaming,» in Etzel Cardena et al., eds., Varieties of Anomalous Experience: Examining the Scientific Evidence (Washington, DC: American Psychological Association, 2000).

9. See Paul Tholey, Schopferisch traumen (Niedernhausen, Ger.: Falken Verlag, 1987).

10. See Stephen LaBerge & Howard Rheingold, Exploring the World of Lucid Dreaming (New York: Ballantine, 1990).

11. S. LaBerge et al., «Lucid Dreaming Verified by Volitional Communication During REM Sleep,» Perceptual and Motor Skills 52:727–732 (1981); and S. LaBerge et al., «Psychophysiological Correlates of the Initiation of Lucid Dreaming,» Sleep Res. 10:149 (1981).

12. For details, see P. Garfield, «Psychological Concomitants of the Lucid Dream State,» Sleep Res. 4:183 (1975); S. LaBerge, «Induction of Lucid Dreams,» Sleep Res. 9:138 (1980); S. LaBerge, «Lucid Dreaming as a Learnable Skill: A Case Study,» Perceptual and Motor Skills 51:1039-41 (1980); LaBerge & Rheingold, Exploring the World of Lucid Dreaming (1990); and G. S. Sparrow, «Effects of Meditation on Dreams,» Sundance Comm. Dream Jour. 1:48–49 (1976).

13. Hobson et al., «Dreaming and the Brain» (2000), 837. For details on the relation between the DLPFC and reflective thought, see A. Muzur et al., «The Prefrontal Cortex in Sleep,» Trends Cog. Sci. 6:475–481 (2002).

14. Tholey, Schopferisch traumen (1987), 97. English translation by T. Metzinger.

15. «Spandrels» refers to Stephen Jay Gould and Richard C. Lewontin's 1979 essay «The Spandrels of San Marco and the Panglossian Paradigm,» in which, using the architectural analogy, the authors argue that some biological features are exaptations: that is, currently used for something other than what they were «developed for» during natural selection. Proc. Royal Soc. London, Ser. B, Biol. Sci. (1934–1990) 205(1161):581–598 (September 21, 1979).