1. S. Weinberg, The Quantum Theory of Fields I, Cambridge University Press, Cambridge, 1995, pp. 144, 145, 198.
2. J. Anandan, Phys. Rev. D33 No. 8 (1986) 2280.
3. E.P. Wigner in The Scientist Speculates, ed. I.J. Good, W. Heinemann, Ltd., London, 1961, reproduced in [8], Ch. 13.
4. It is emphasized that in the present interpretation of quantum mechanics, 'consciousness' plays no special role in collapsing the wave function. Or the argument may be turned around, and it may be claimed that even a microscopic system being in a mixed state in relation to its interaction with another system may constitute a primitive form of 'consciousness'.
5. J.C. Pati and A. Salam, Phys. Rev.8 (1973) 1240; Phys. Rev. Lett.31 (1973) 661; Phys. Rev. D10 (1974) 275. For a recent review, see J.C. Pati, hep-ph/0204240.