ENDNOTES

<1>:Barbour 1966: 326-7. Also see Birch 1979: 56-7; Hartshorne and Reese 1953; and Jaki 1966: Chap. 1.

<2>:See, for instance, Birch and Cobb 1981: 132-3.

<3>:Smith 1982: 668.

<4>:Capra 1977a.

<5>:Sharpe 1987.

<6>:Sharpe 1990; 1991.

<7>:Popper 1982: 36. See also Bohm 1988: 111-4; Jammer 1988: 692; and Sudbery 1988.

<8>:Bohm, Hillion, Takabayasi and Vigier 1960; Bohm, Hillion and Vigier 1960; and De Broglie, Bohm, Hillion, Halbwachs, Takabayasi and Vigier 1963: 438-9. That elementary particles are extended structures has become an important contemporary research question in the guise of superstring theories. See Anthony and Green 1985; Brown 1991; Davies and Brown 1988; Freedman and van Niewehuizen 1985; Green 1986; Taubes 1986; and Thomsen 1986g.

<9>:Bohm and Hiley 1975: 95.

<10>:Hiley 1980: 80-1.

<11>:Barbour 1966: 300-1.

<12>:Barbour 1966: 299 (see also Barbour 1955: 11); Bohm and Hiley 1982; and Toulmin 1962: 17.

<13>:See Bohm 1987c; and Earman 1986.

<14>:Gudder 1979: 59.

<15>:Marshall 1985: 265-7; Siegel 1963; Temple 1982: 364; and Vigier 1957: 77. Cushing 1991b: 39 suggests Bohm's approach anticipates and agrees with that of modern chaos theory (see also Anon. 1990b). Lindsay 1957: 32 accuses Bohm of identifying causality with determinism. As in its title, Bohm 1957a deals in depth with the questions of causality and chance (see also Bohm and Schützer 1955; and Osborne 1985). For a discussion of causality and science, see Puterman 1977. Marshall 1985: 266 claims "Bohm's theory between 1952 and 1980 has evolved...toward acausality." Dingle 1970 derives a theory of causality for quantum physics that he feels Bohm fathered.

<16>:Some describe Bohm's hidden variables/quantum potential interpretation of quantum physics as being like a sub-quantum dynamic fluid interpretation, and it is often incorporated under stochastic approaches. In this the velocity of a particle has a random component in addition to what it has in his causal theory (even though Zeilinger 1988 criticizes calling Bohm's theory causal, I will follow the custom of doing so). See Bohm and Hiley 1989; 1991; Fine 1989; Petroni 1985: 199; Tarozzi and van der Merwe 1985: Part 2; and Wheeler and Zurek 1983: 779.

<17>:Jeffreys and von Neumann, respectively, quoted in Hanson 1958: 153 and 230; see also ibid., p. 172.

<18>:Toulmin 1962: 9.

<19>:Besides hidden variables and related matters foundational to quantum physics, Bohm has written on several subjects including the many-body problem and plasma physics, the theory of the synchrotron, and the self-oscillations of a charged particle; see Bohm 1959; Bohm and Carmi 1964; Bohm and Foldy 1946; 1947; Bohm and Gross 1948; 1949a; 1949b; 1950; Bohm, Huang and Pines 1957; Bohm and Peat 1987: 4-5; Bohm and Pines 1950; 1951; 1953; Bohm and Weinstein 1948; Bohm, Weinstein and Kouts 1949; Carmi and Bohm 1964; Ford and Bohm 1950; and Pines and Bohm 1952. See also Gross 1987; and Pines 1987. His work on plasma physics is foundational to the subject; see Amini 1985; Aston 1980; Carini 1983; Coakley 1980; Hiley and Peat 1987b: 3; Main 1984; and Parish 1980.

<20>:Briggs and Peat 1984: 95-6; 1987: 70. See also Jammer 1988: 691.

<21>:Bohm 1951: 29 and 623; see also pp. 101, 114-5, 139, and 622-3.

<22>:Folse 1985 provides interesting background on Bohr's own holistic thinking; see especially pp. 48-9. See also Folse 1987; and 1989b.

<23>:Bohm and Hiley 1982: 1014. See also Bernstein 1984/85: 8; Jammer 1974: 219, 279; Temple 1982: 361-2; and comments by Yuval Ne'eman and Abraham Paris in Woolf 1980: 267.

<24>:Belinfante 1973: xvi.

<25>:Bohm 1957a: ix-xi; 1980b: 76; 1988: 14; Bohm and Hiley 1982; 1984: 256, referring to de Broglie 1960; and Jammer 1988: 694. See also de Broglie 1926; 1927a; 1927b; 1928; 1963; 1970; 1987; and Flato, Maric, Milojevic, Sternheimer and Vigier 1976. Madelung could be added to de Broglie's name as giving a precursor to Bohm's theory; see Wesley 1983: 105-8. Jammer 1974: Chap. 7; Kaliski 1970; Rosen 1985; and Wheeler and Zurek 1983: 777-8 survey hidden variables theories including those prior to Bohm's.

<26>:Bohm 1952a; 1952b; 1952c; 1953a; 1953b; 1953c; 1953d; 1962a (as 1980b: 76-110); Bohm, Schiller and Tiomno 1955; Bohm and Vigier 1954; and 1958. See also Blokhintsev 1978: Chap. 14 (reflecting his early 1950s work); Bohm and Hiley 1975: 96-101; Belinfante 1973: Part II, Chap. 2; de Broglie 1960: Part 2; d'Espagnat 1983: 90-1; Epstein 1952; 1953; Fényes 1952; Freistadt 1953: 220-1; 1957; Halpern 1952; Harvey 1966; Jammer 1988: 694; Kershaw 1964 (note Nelson 1966); Régnier, Schatzman and Vigier 1952; Rosenfeld 1953: 403-4; Schatzman 1952; Steiger 1954; Takabayasi 1952; 1953; 1984; Vigier 1952; Weizel 1953a; 1953b; and 1954. With regard to de Broglie and his objectors, see Bohm 1952b; Bohm 1953b: 283; Bohm and Hiley 1982: 1003, 1014; Bohm and Vigier 1954; de Broglie 1960: Chap. 14; 1963: 131-3; Dewdney and Hiley 1982: 28; and Jammer 1974: 111-4.

<27>:Jammer 1988: 692.

<28>:Keller 1953; and Pauli 1953 are two publications posing important difficulties to which Bohm and Vigier 1954 reply. Halpern 1952 is replied to in Bohm 1952c (see also Belinfante 1973: 118-21; and Jammer 1974: 278-96 - but with regard to this last reference, see also Temple 1982: 364). Takabayasi 1952 and 1953 are replied to in Bohm 1953b. For a list of criticisms, also see Rosenfeld 1957; 1958 (but see also de Broglie and Rosenfeld 1958). See also Finkelstein 1987: 289.

<29>:Bohm 1957b: 33.

<30>:Bohm 1953b: 280-1.

<31>:Davies and Brown 1986: 133-4.

<32>:In his initial exposition on hidden variables Bohm writes that, while the usual interpretation of quantum theory is consistent, it is based on an experimentally untestable assumption related to the one Heisenberg had made. This tenet is that the most complete specification possible for a system is in terms of a wave function that, because of its mathematical definition, can only determine the probable result of an actual measurement. He considers there is only one way to investigate the truth of this assumption, and that is to use an alternative interpretation of the quantum theory in terms of variables that are at present hidden. See Bohm 1952a: 166. For an elaboration on the notion of probability used here, see Vigier 1957.

<33>:Bohm 1953c: 458. See also Bohm 1980b: 65; and Bohm and Vigier 1954.

<34>:Bohm 1952a: 166; 1957b: 33, 35-7; see also Bohm 1980b: 78.

<35>:Bohm 1952a: 166.

<36>:See Belinfante 1973: 94; and Bell 1982.

<37>:Aharonov and Albert 1987: 224; Bohm 1953b: 279; and Jammer 1988: 694.

<38>:Bohm 1952c; and Bohm and Vigier 1954: 215.

<39>:Bohm and Bub 1966a: 462; see also their 1966b; 1968; Bohm 1969a: 443-6; 1971c: 102-16; 1980b: 80-110; Belinfante 1973: Part II, Chap. 4; Bub 1968; 1973: 51; and Jammer 1974: 312-8. Cerofolini considers the Bohm-Bub hidden variables theory to be formally equivalent to his sub-quantum physics; see Cerofolini 1982; and 1988.

<40>:Dewdney and Hiley 1982: 47; Landergott 1973; and Tutsch 1968: 232. See also Tutsch 1969. For instances of its modification, see Tutsch 1968; and Belinfante 1973. It is interesting to note, as well, that the Birkbeck School consider the Bohm-Bub theory to be an extension or modification or restatement of the original Bohm version, whereas many commentators treat them as two different, though related, theories; see Bohm and Hiley 1975: 97; and Jammer 1988: 695.

<41>:Longtin and Mattuck 1984: 685-6.

<42>:Actually, it is a quantum mechanical state vector that collapses into an eigenstate.

<43>:Bohm and Bub 1966a: 453. But see Christensen and Mattuck 1982.

<44>:Bohm and Bub 1966a: 466; see also Bohm 1980b: 82-5, 105-9. Papaliolios 1967.

<45>:Bohm 1969a: 446. See also Papaliolios 1967: 624; Tutsch 1968: 232; and 1969: 1116.

<46>:Freedman, Holt and Papaliolios 1976: 47. See also Belinfante 1973: xvi, 163 and Part II Chap. 5.

<47>:Bohm and Bub 1966a: 467; Bohm 1988: 112; Belinfante 1973: 162. See also Bell 1987b.

<48>:Hanson 1958: 173. See also his 1963: Chap. 6; and Jammer 1988: 694. Bohm showed Pauli's criticisms were wrong.

<49>:Quoted in Jammer 1988: 694.

<50>:Von Neumann 1955: x, 209-11, 323-8; Bohm 1971c: 97-102; Bohm 1980b: 70-1; Bohm and Bub 1966a: 460-2. See also Capasso, Fortunato, and Selleri 1970; and Clauser and Wigner 1971. A summary of von Neumann's ideas can be found in Bell 1966 (regading Bell, Bohm, and von Neumann, see also Crease and Mann 1988: 88-90); and in Jammer 1974: 265-78. See Jauch and Piron 1963: 827-9 for a history of the question and of von Neumann's results. Popper 1982: 11-4 provides further historical background. Albertson 1961; and Zinnes 1958 restate von Neumann's proof in other forms.

<51>:Belinfante 1973: Part I and 162; Jammer 1974: 296-302, 312-39. For other difficulties it faces, see Tutsch 1969: 1116ff; and Teller 1977.

<52>:Jauch and Piron 1968: 228. See also Jauch 1968: Chap. 7; 1976; and Jauch and Piron 1963, which is based on a formulation of quantum physics by Piron published in 1964. Piron 1972 simplifies Gleason's 1957 theory.

<53>:Gudder 1968a: 231; see also Greechie and Gudder 1973; Gudder 1968b; 1979: 60-1; and 1983: 114-6.

<54>:Bell 1966 tries to prove that the arguments of von Neumann, of Jauch and Piron, and of Gleason, make unreasonable assumptions. He is also critical of the attempts by Bohm up to a 1962 publication to undermine von Neumann's theorem (see also Bell 1987). See, for instance, Bohm 1952b.

<55>:Tutsch 1968: 232. See also Bohm and Bub 1968; Hübner 1983: 80-1; Jauch and Piron 1968; and Turner 1968. For instance, Bohm and Bub think Jauch and Piron's argument is circular. For Jauch and Piron to conclude hidden variables cannot exist requires an assumption. This assumption is equivalent to their conclusion that current quantum physics is the only theory that correctly describes experimental results. See Bohm and Bub 1966b: 470. Bub 1974b surveys this whole question; see also Bub 1976; 1977; and MacKinnon 1981. Bub still finds the relationship between these various proofs and hidden variables theories obscure, even after what he calls Bell's excellent analysis. See Bub 1969: 101.

<56>:Misra 1967: 841-3. Bohm 1957a states this criticism thoroughly.

<57>:The reasons Misra raises against the hidden variables theories of Bohm, and Bohm and Bub do not seem convincing; they could be just as strong in motivating a person to improve those theories.

<58>:Rédei 1986 attempts to strenthen Misra's case. Gudder's later approaches are similar to Misra's. He shows the proofs of von Neumann and his successors do rule out some hidden variables theories. He thinks, however, that a type of hidden variables theory is possible for quantum physics. He thinks this even though these theories do not seem any simpler or better to him and people rarely use them. Examples he gives are the theories of Bohm and Bub, Einstein, and his own. See Gudder 1979: 59-65; see also Gudder 1970: 431-2: a hidden variables "theory is always possible" in quantum physics in its present framework. Ochs 1972 challenges Gudder; the latter replies in his 1972. He may have more recently changed his mind about the desirability of using hidden variables; see Gudder and Armstrong 1985. Jordan and Sudarshan 1991 show that quantum mechanics allows no hidden variables at all.

<59>:Bub 1969: 101-2 (he reiterates the same ideas in a book - 1974b; see also his 1981 - a few years later); Kochen and Specker 1965; 1967; and Specker 1975. See also Bub 1968; Demopoulos 1977; Latzer 1974; and Smith 1977: 345.

<60>:Bub 1969: 102.

<61>:Tutsch 1969: 1116.

<62>:Bohm and Hiley 1984: 259; and Bohm 1969a: 446. See also ibid., pp. 446-7; and Bohm and Bub 1966a: 466.

<63>:Popper 1985: 15-6.

<64>:Bohm and Hiley 1984: 259. See also de Muynck 1987.

<65>:Quigg 1985: 84.

<66>:Hawking 1985: 146-7.

<67>:Hiley relates in his 1971: 181 that his motivation for attempting to go beyond quantum theory springs mainly from the problems arising at very high energies. He believes the root of the difficulties is in the quantum description. At the low energy domain there is no reason to question its validity. He goes on to show how the holomovement theory now promoted by the School may solve the problems raised (ibid., pp. 188-9).

<68>:Philippidis, Dewdney and Hiley 1979: 17. See also Temple 1982: 362.

<69>:Jammer 1988: 693 describes this well. Honig 1988 interprets the quantum potential with his "fluid droplet electron model." Compare also with Kyprianidis's use of the Hamilton-Jacobi theory.

<70>:See, for instance, Philippidis, Bohm and Kaye 1982. Bohm, Hiley and Kaloyerou 1987: 323-48 discuss the quantum potential theory in detail, in particular showing how it produces the differences between the classical and the quantum theories (see also Bohm 1988b).

<71>:Bohm and Hiley 1976b: 176-7; Davies and Brown 1986: 39; and Jammer 1988: 696. See also Bohm and Hiley 1975: 97-9; 1982: 1005-6; 1984: 259-62; Bohm, Dewdney and Hiley 1985: 296; and Philippidis, Dewdney and Hiley 1979: 27.

<72>:Philippidis, Dewdney and Hiley 1979: 25; but their result has been criticized as not fitting the double slit flux that is actually observed - see Wesley 1983: 107. See also Hiley 1985: 239-42. Dewdney 1987; 1988c; and 1988d describe how the Birkbeck interpretation accounts for two-particle, nonrelativistic quantum mechanics. Another paper uses the quantum potential approach to describe "one-dimensional time-dependent scattering of wave packets from square barriers and square wells"; Dewdney and Hiley 1982: 27 - see also Dewdney 1985; 1988a; Dewdney and Holland 1988; Hiley 1985: 245-8; and Lam and Dewdney 1990. See also Bell 1987b; and Holland 1982.

<73>:Bohm and Hiley 1984: 260.

<74>:Bohm and Hiley 1980: 267-9 also distinguish between active information and inactive information. They thus move to the solution of the measurement problem that the following section discusses. See also Davies and Brown 1986: 128; and Horodecki 1988.

<75>:Bohm and Hiley 1985; Halpern 1986; and Thomsen 1986f: 27. Quantum theory is now finding several other applications at the macroscopic level; see, for example, Clark 1987; Leggett 1984; and 1988.

<76>:Bohm, Dewdney and Hiley 1985: 297; but see Umakantha, Bohm, Dewdney and Hiley 1986. Davies and Brown 1986: 38-9 suggest that the quantum potential approach could mean signals travel backwards in time, thus creating a causal paradox. Bohm ibid., pp. 125-6 does not agree; neither does Hiley (ibid., pp. 141-2).

<77>:Bohm and Hiley 1984: 256; see also ibid., p. 260; and Bohm 1984: 781 (in which he refers to Bohm and Hiley 1982: 1001).

<78>:Bohm and Hiley 1976b: 175.

<79>:Bohm, Dewdney and Hiley 1985: 297. See also Philippidis, Bohm and Kaye 1982: 80.

<80>:Bopp, quoted in Philippidis, Dewdney and Hiley 1979: 18. Bopp also says Bohm's theory is not "physics but metaphysics"; Körner 1957: 51.

<81>:Bohm and Hiley 1984: 257. Concerning the measurement problem, see, for instance, Rae 1986; Smolin 1985: 40-1; and Wigner 1963.

<82>:Bohm and Bub 1966a: 457. See also Bell 1966: 448, n. 8; and Bub 1969: 121-2.

<83>:Dewdney and Hiley 1982: 46-7. Bohm 1969a: 439-43 describes how this assumption of the completeness of the reigning quantum theory leads to the measurement problem. There are many publications assessing the inadequacies of the Copenhagen interpretation and suggesting the need for another one; see, for example, Hodgson 1989; and Stuart 1991.

<84>:Some even say consciousness is a hidden variable. See, for example, Ballentine et al. 1971: 39; Bohm and Hiley 1976b; d'Espagnat 1969; Gardner 1982; Gribbin 1984: 205-13; Smolin 1985: 42-3; Snyder 1989; Talbot 1981: Chap. 1; Toben, Sarfatti and Wolf 1975: 11, 134; Trigg 1980: 154-60; Walker 1974; Wassermann 1983; Wheeler 1977b; and Wigner 1962; 1963; 1969a; 1969b; 1970b; 1970c; 1972; 1973. However, also see Bohm and Hiley 1976b: 173; Bohm, Dewdney and Hiley 1985: 294; and Rae 1986: 63-74. Von Neumann would say the change of state of a physical system being observed is completed only when the observer's consciousness registers the result of the observation. For critiques of von Neumann's and of Bohr's (inseparability of observer and observed) approaches, see Shimony 1963. Cramer's 1986 interpretation of quantum mechanics is similar to Wigner's; see Thomsen 1987.

<85>:Bohm and Hiley 1984: 257. Shimony 1963: 772-3, n. 33 is a brief assessment of Everett's "many worlds" solution; see also Ballentine et al. 1971; Bohm, Hiley and Kaloyerou 1987: 346-7; DeWitt 1968; 1970; 1971; Everett 1957; Wheeler 1957; other papers in DeWitt and Graham 1973; and, for a popular account, Gribbin 1984: Chap. 11. Bell 1981 interestingly likens the Everett theory with that of Bohm (and de Broglie). See also Wilber 1982b: 172-9. Squires 1987 suggests a related view to Everett's, the "many views of one world" interpretation (see also Anon. 1987b).

<86>:Bohm and Hiley 1984: 257. See also ibid., pp. 268-9; Bohm 1969a: 444; Bohm and Hiley 1984; and Dewdney, Garuccio, Guéret, Kyprianidis and Vigier 1985. Zeh 1988 criticizes both the Birkbeck and Everett's solutions to the measurement problem. Thomsen 1986d describes recent developments about the measurement problem.

<87>:Bohm 1952a: 167; 1957a: Chap. 3; 1969a: 439; 1980b: 65-76; but see Stapp 1972; and 1985c. See also Trigg 1980: 156.

<88>:One can also talk of the random thermal motions of the particles comprising the apparatus significantly affecting the particle being observed, but that cannot be controlled or predicted exactly.

<89>:Bohm and Hiley 1984: 256-7; Bohm 1980b: 88-105; and Hiley 1985: 249-54. There is a discrepancy between the early and the later Heisenberg with regard to this; see Temple 1982: 364.

<90>:Bohm 1957b: 33-7; and Bohm 1952b.

<91>:Bohm 1969a: 439-43; and Dewdney and Hiley 1982: 46-7. Related to the above discussion, see Hübner 1983: Chap. 2 for a critique of both Bohm's and the Copenhagen approaches to the question of causality; Fröhlich 1987; and Rosen 1987.

<92>:Toulmin 1962: 17-9.

<93>:Bohm 1953b: 283-5.

<94>:Cranston 1974 develops Bohm's idea of causality further. The nonlocality results of the EPR experiments described in later chapters beg the question of causality; see Skyrms 1985.

<95>:Bohm 1969a: 439-43.

<96>:Bohm 1969a: 439-43.

<97>:Bohm and Hiley 1984: 256.

<98>:Belinfante 1973: 164; but see Bohm 1971c: 112-3; Bohm and Bub 1966a: 466; and Fox and Rosner 1971. See also Audi 1973: 97; Putnam 1965: 87; Körner 1957: 46-89; and the interesting comments in Feyerabend 1960: 326, n. 1. The same statement is made much later in Bohm and Hiley 1984: 255.

<99>:Quoted in Feyerabend 1960: 330, n. 1. See also de Broglie and Rosenfeld 1958; and Rosenfeld 1953: 403-4.

<100>:Peres 1978: 745.

<101>:Popper 1982: 174-5.

<102>:Finkelstein 1987: 292-3.

<103>:Hanson 1962: 91-3. See also Anon. 1966; and Hanson's criticism in his 1963: Chaps 5 and 6.

<104>:This is a different mood about Bohm's work for Hanson than the one he expressed in the conclusion to his famous 1958 publication (pp. 174-5): "At this stage it would be venturesome to try finally to settle this matter; nonetheless...its conceptual significance will be missed by anyone who fails to see how much was at work when physicists of the past disagreed, and missed also by anyone who thinks of the history of physics as just a march of better observations and more accurate experiments." See also Heisenberg 1955: 17-9; and 1958: 130-3, where he argues that Bohm's hidden variables proposal says nothing about physics that is different from what the Copenhagen interpretation says. He then goes on to argue against choosing Bohm's language as being more suitable than the Copenhagen side because it is not an improvement. Bohm replies in his 1962c.

<105>:Polkinghorne 1988: 339; see also Polkinghorne 1984: 57; 1986: 10-1; and 1989: 83. Despite what Polkinghorne writes, Bohm's theories do now apply in relativistic situations, as I mention below. Russell 1988: 371, n. 12 similarly questions Polkinghorne's appraisal of Bohm regarding special relativity and his underlying philosophical judgements. See also Cushing 1991a; and 1991b.

<106>:D'Espagnat 1983: 16.

<107>:Jauch 1976: 123.

<108>:Smolin 1985: 43. See also Rosen 1985.

<109>:von Weizsäcker and Görnitz 1991.

<110>:Honig 1987a: xiv.

<111>:Barbour 1966: 299-301; Garstens 1971: 87; and Körner 1957: 51.

<112>:Bohm 1957a. Russell 1983 analyzes Bohm's hidden variables physics as a research program. In this context its philosophical strengths and weaknesses in comparison with those of the Copenhagen school clearly emerge.

<113>:D'Espagnat 1986: 944. See also his 1987d.

<114>:Bohm and Hiley 1984. See also Bell 1987b; Bohm and Hiley 1985b; 1991; Hiley 1989: 11-4; 1989b: 187-8; and Moylan 1982.

<115>:Longtin and Mattuck 1984: 685. Two years previous to this, an article appeared written by Mattuck and Christensen that details the modification of the original Bohm-Bub hidden variables theory through the work of Tutsch and Belinfante, but which still was inadequate because it was not relativistically covariant; Christensen and Mattuck 1982: 348.

<116>:Bohm, Hiley and Kaloyerou 1987: 349-75; Kaloyerou 1985; and Lima Vargas Moniz 1988; see also Bohm 1988: 119-21; Bohm and Hiley 1991; Hiley 1989: 11; and Pitowsky 1991.

<117>:Bohm, Dewdney and Hiley 1985: 294; Hellmuth, Zajonc and Walther 1985; Jonas 1986; Miller and Wheeler 1984; Thomsen 1986h; Umakantha, Bohm, Dewdney and Hiley 1986; and Wheeler 1978. The quantum potential approach also accounts for the results of neutron interferometry experiments (see Dewdney 1988a; and 1988b) and for an anomalous photoelectric effect (see Kyprianidis 1987).

<118>:Tutsch 1968: 234. He elaborates his thoughts further in Tutsch 1969.

<119>:Bohm and Hiley 1989; and 1991: 247-9. See also Anon. 1990; and Götsch, Koch, Lüning, Scheer, and Schmidt 1988. Panarella 1987 claims experimental preference for the effective photon hypothesis approach to quantum theory over that of the quantum potential theory.

<120>:Toulmin 1962: 11, 19-22.

<121>:Temple 1982: 365; see also Maxwell 1988; Peat 1988; Penrose 1989: 280-1; and Rosen 1988. Casti 1989: 491 says that, while his mind is with the quantum potential approach, his heart is not; his is a half-way step.

<122>:There are, of course, other hidden variables theories both before and after Bohm's proposals, and these also continue to foster research interest. See, for example, Accardi 1988; Belinfante 1973; Fine 1974; 1989; Flanagan 1988; Graber 1989; Gudder 1972; 1980; 1984a; 1984b; Gudder and Armstrong 1985: 1009, which refers to some more recent attempts; Hnilo 1991; Honig 1987a; 1987b; Pignedoli 1988: 188-9; Pitowsky 1983; Pollini 1988; Rédei 1985; 1986; Robinson 1985; and Shimony 1986 (Shimony 1984b; and 1989: 387-9, 395 questions Bohm's program; Bohm and Hiley 1984b reply; and Shimony 1989b: 30 furthers the discussion). Vigier 1980 finds new impetus for continuing the development of a version of hidden variables theory akin to, but not the same as (Bohm and Hiley 1984b; Bitsakis 1985: 69) Bohm's (Bohm and Vigier 1954; 1958). See also Andrade e Silva, Selleri and Vigier 1983; Barut, Bozic and Maric 1988; Croca 1987; Cufaro-Petroni 1987; 1988; 1988b; Cufaro-Petroni, Dewdney, Holland, Kyprianidis and Vigier 1984; 1985; 1985b; 1987 (but see Costa de Beauregard 1987); Cufaro-Petroni, Droz-Vincent and Vigier 1981; Cufaro-Petroni, Garuccio, Selleri and Vigier 1980; Cufaro-Petroni, Gueret, Kyprianidis and Vigier 1985; Cufaro-Petroni, Guéret and Vigier 1984a; 1984b; 1988; Cufaro-Petroni, Gueret, Vigier and Kyprianidis 1985a; 1985b; Cufaro-Petroni, Kyprianidis, Maric and Vigier 1984; Cufaro-Petroni, Maric, Zivanovic and Vigier 1980; 1981; Cufaro-Petroni and Vigier 1981; 1982; 1983; 1983b; 1983c; 1984; Dewdney, Garuccio, Guéret, Kyprianidis and Vigier 1985; Dewdney, Garuccio, Kyprianidis and Vigier 1984; 1984b; Dewdney, Guéret, Kyprianidis and Vigier 1984; Dewdney, Holland and Kyprianidis 1986; 1987a; 1987b; Dewdney, Holland, Kyprianidis, Maric and Vigier 1986; Dewdney, Holland, Kyprianidis and Vigier 1985; 1986a; 1986b; 1988; Dewdney, Kyprianidis and Vigier 1984; Dewdney, Kyprianidis, Vigier, Garuccio, Guéret 1984; Garuccio 1985; Garuccio, Kyprianidis, Sardelis and Vigier 1984; Garuccio, Kyprianidis and Vigier 1984; Garuccio, Popper and Vigier 1981; Garuccio, Rapisarda and Vigier 1982; Garuccio and Vigier 1980; Guéret 1985; Guéret, Holland, Kyprianidis and Vigier 1985; Guéret and Vigier 1982a; 1982b; 1982c; 1983; 1984; Halbwachs, Piperno and Vigier 1982; Holland 1987; 1988b; Holland, Kyprianidis and Vigier 1985; Holland, Kyprianidis, Maric and Vigier 1986; Holland and Vigier 1985; 1988; Kamefuchi et al. 1984: 368; Kyprianidis 1985; 1988a; 1988b; Kyprianidis and Sardelis 1984; Kyprianidis, Sardelis and Vigier 1984; Vigier 1982; 1985; 1985b; 1987; 1988; 1988b; 1991; and Vigier, Dewdney, Holland, and Kyprianidis 1987. Wesley 1983; and 1988 develops a causal theory based on the quantum potential and Bohm's early work; see Phipps 1985. See also Ryff 1990.

<123>:Current superstring physical theories share this in common with those of Bohm, that they shy away from considering particles as extensionless points in a co-ordinate frame - the former treat particles as extended objects. See Anthony and Green 1985.

<124>:Bohm 1963b; 1969b; 1971d: 361-2, 367; Briggs and Peat 1984: 106-8; and Hiley 1980: 81. Note also that the word "order" is something Bohm finds he cannot define. He can only intimate its use b