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Postscript-The Hammer and the Pendulum

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Postscript-The Hammer and the Pendulum Postscript-The Hammer and The Pendulum To my mind there appears to be no necessary theoretical antagonism between Catastrophism and Uniformitarianism. On the contrary, it is very conceivable that catastrophes may be parr and parcel of uniformity. Let me illustrate my case by analogy. The working of a clock is a model of uniform aCtion; good time-keeping means uniformity of aCtion. But the striking of the clock is essentially a catastro­ phe; the hammer might be made ro blow up a barrel ofgunpowder, or turn on a deluge of water; and, by proper arrangement, the clock, instead of marking the hours, mighr strike ar all sorrs of irregular intervals, never twice alike in the intervals, force, or number of its blows. Nevertheless, all rhese irregular and apparenrly lawless carastrophes would be rhe resulr of an absolurely uniformi­ tarian action action; and we mighr have twO schools of clock-rheorisrs, one studying the hammer and rhe other the pendulum. Srill less is rhere any necessary antagonism berween eirher of rhese doctrines and rhar of Evolurion, which embraces all rhar is sound in borh Carastrophism and Uniformirarianism, while ir rejeCts rhe arbirrary assumprions of rhe one and rhe, as arbitrary, limirarions of rhe orher. Nor is rhe value of rhe doCtrine of Evolurion to the philosophic rhinker diminished by rhe faCt rhar ir applies rhe same merhod ro rhe living and rhe nor-living world, and embraces in one stupendous analogy rhe growrh of a solar sysrem from molecular chaos, rhe shaping of rhe earth from rhe nebulous cubhood of irs yourh, rhrough innumerable changes and immeas­ urable ages, to irs present form, and rhe development of a living being from rhe shapeless mass of proroplasm we rerm a germ. T.H.Huxley, Anniversary Address of the President, Quarterly journal ofthe Geological Society ofLondon 25, xlvi-xlvii (1869) A shorr extract from Thomas Huxley's address to the Geological Society 10 1869, just ten years after the publication of Charles Darwin's On the Origin ofSpecies, 345 346 Postscript-The Hammer and the Pendulum was quoted in Section 2.8. The rather longer quorarion from rhe same section given above enables us to see JUSt how perceptive Darwin's "bulldog" was, in recognizing thar the course of evolution must have involved catastrophic events as well as gradualist processes, all operating within the framework of natural laws. However, his wise words were ignored for well over a century, during which time it was thought that the only mechanisms worthy of consideration were rhose consistent with gradualism. Only now, at long last, is it becoming possible I(lr debates about the contribution of catastrophism to evolutionary ptocesses to take place in a proper, open-minded, fashion. That is not to say that they are always conducted in an atmosphere of sweet reasonableness for, as with any academic discussion where there is more than one school of thought and particularly where, as here, fundamentally different worldviews are involved, passions continue to be aroused and prejudices displayed. Nevertheless, they are happening, and that in itself is a step forward. No one can now suggest, and retain any credibility, that carastrophist mecha­ nisms should, as a matter ofprinciple, be excluded from consideration. All arguments, whether catastrophist or gradualist, have to be judged on equal terms, by testing them against the evidence. That is as it should be. Without any question, debates over the past 15 years about the possible influence ofcatastrophism on evolution have proved consistently lively and increasingly productive. Let us hope the same is true ofthe next 15 years. Despite the recent advances, there are still an enormous number of questions that need to be answered. References Chapter 1 1. H. Couper and N. HenbesL The Planets, Pan Books. London (1985). 2. P Moore, New Gllide to the Planets. Sidgwick and Jackson. London (1993); P Moore, Stan and PICllleIJ, Chancellor Press, London (1992). 3. c.]. Allegre and S. H. Schneider, The evolution of the Earth, Sci. Alii. 271(4),44-5 I. ([994); S. R. Taylor, Solar Systelll E"ollilioll, Cambridge University Press (1992); S. Bowler. Formarion ofrhe Earth. Neu'Scientist 14 December 1996, IltSitie Srimce supplement number 96, pp. 1-4; N. Murray, B. Hansen, M. Holman, and S. Tremaine, Migraring planets, Science (Wash .. DC) 279. 69-72 (1998); I. icolson, D. A. Rorhery, and F. Taylor. Focus: Binh of rhe Solar System. AitI'OIIOIll)' Noll' 12(2l. 4 I-50 (1998); T. Yulsman, From pebbles m planers, /IStroIlOIllY 26(2). 56-(, I (199S); C. Dwyer. Laplace-rhe Supreme calculamr. /ISlI'OIIOIII)' Now 12(5), 52-53 (1998). 4. A. Roy (ed.), Oxford IIImtrateel EIltJdoptdia of the Univene. Oxford Universiry Press (992); V Illingworrh (ed.l. Col/illS Dictional) ofAstronomy, HarperCollins, London (994). 5. C. Sagan and A. Druyan, Shadows ofForgotltn Ancestors, Century, London (1992). 6. N. HenbesL The Planets - Portmits ofNew Wor/ds, Penguin Books, Harmondsworrh (1994). 7. T. Gehrels (ed.), Hazards Dlle 10 COllltlS alld ASlemids, University of Arizona Press, Tucson (1994). 8. ]. Gribbin and M. Gribbin. Fire 011 Earlh - III Searrh ofIhe Doolllsday ASleroid, Simon & Schuster, London (1996); .J. S. Lewis, Rain of Iron and Ire - The lie". Real Thrwt of COlllet and /lstemid BOll/hardlllml, Addison-Wesley, Reading, MA (1996). 9. G. L. Verschuur, IlIIpact - The Threat ofColllets alltl Asteroids, Oxford University Press (1996). 10. B. Parker, Chaos illlhe Cosmos. Plenum Press, New York and London (1996). II. A. Milani, Emerging stability and chaos, Natlll'< (Lond.) 338, 207-208 (1989); .J. Laskar, A numerical experiment on the chaotic behaviour of the Solar System, Nallire (Land.) .'->8, 237-238 (1989); C. Murray, Is the Solar System stable', New Scienlist, 25 November. 60-63(989); C. Murray, Is the Solar System stable', in: The New S,ienti,rt Gllide to Chaos (N. Hall, ed.), Penguin Books, Harmondsworth (1992), pp. 96-107. 12. K. Croswell, Plum's moon is a giant snowball, NewScimtist 21 November, 16 (1992); R. Lorenz, All aboard the Pluro express, New S,ientist 25 May, 34-37 (1996); I. Nicolson, Distant giants and tiny Plum, Astronomy Now 11(6), 28-29 (1997); A. Stern and]. Minon. Pilito and Charon, Wiley, New York (1998); P Moore, Worlds on the edge, New Scimtist ., January, .,8-39(998). 13. ]. Kinoshita, Neptune, Sci. Am. 2(,1(5),60-690989); R. Berry, Triumph at Neptune, Aitmnolll)' 17( II), 20-2S (1989); R. Berry, Neptune revealed, /1stronolll)' 17( 12), 22-34 (1989l. 347 348 Controversy-Catastrophism and Evolution 14. R. Berry, Uranus: the voyage conrinues, Astronomy 14(4),6-220986>. R. Berry, Voyager: discovery at Uranus, Astronom)' 14(5),6-22 (986). 15. A. P.1ngetsoll, Uranus, Sci. Am. 256(1), 30-37 (1987); T. Y.Johnson. R. Hamilwn Brown, and L. A. Soderblom, The moons of Uranus, Sti. Am. 256(4),48-60 (987). iSee also M. A. Garlick, Two moons for Sister Uranus, Mod. Astronom. 1( 10),7 (1997); Two new moons for Uranus,Sk)'antlTeleJcop, 95(1),19 (1998); B.]. Gladman, P. D. Nicholson,]. A. Burns,].]. Kavelaar, B. G. Marsden, G. V. Williams, and W B. Offutt, Discovery of twO distanr irregular moons of Uranus, Natlire (Land.) 392,897-899 (1998). 16. C. R. Chapman and D. Morrison, (;osmit Catastrophes, Plenum Press, New York and London (1989). 17. D. G. Jankowski and S. W Squyres, Solid-stare ice volcanism on th,· sarellires of Uranus, Science (Wash., D0241, 1322-1325(988). 18. ]. B. Plescia Geological terrains and crater frequencies on Ariel, N'/Ilm (Lond.) 327, 201-204 (1987). 19. ]. N. Cuzzi and L. W Esposito, The rings of Uranus, Sci. Am. 2570),i2-48 (987). 20. ]. K. Davies, (;osmit Impaas, St. Martins Press, New York (1986). 21. L. A. Soderblom and T. Y. Johnson, The moons ofSaturn, Sci. Am. 24(,,1), 100-116(982). 22. R. Berry, Voyager: science at Saturn, Astronom)' 9(2), 6-22 (1981). 23. R. Berry and R. Burnham, Voyager 2 at Saturn, Astronomy 9( 11),6-30 (1<)81); H. Muir, Seven new satellites for planet Saturn. New Scientist 5 November, 16 (1994). 24. R. Burnham, The Saturnian moons, Astronom)' 9( 12), 6-24 (1981). 25. L. A. Soderblom, The Galilean mnons ofJupiter, Sci. Am. 242( 1),68-83 ( 1980);]. Spencer,Jupiter's odd bunch, N,w Sci,mist 5 April, 42-45 (1997). 26. L. W Esposiw, Understanding planetary rings, Annll. Ret·. Earth Plan't. Sci. 21. 487-523 (993). 27. A Neptune pictorial. Astronol!l)' Now 3( 12), 27-.30 (1989). 28. C. C. Porco, An explanation for Neptune's ring arcs, Sciwce (Wash.. DC! 253, 995-1001(991); P. Bond, New theory of Neptune's ring arcs, Astronomy Now 1\(9),5099 ). ' 29. D.]. Stevenson, Origins of [he Moon - [he collision hypothesis, Amw Rm Earth Planet. Sci. 15, 271-315 (1987). 30. A. Ringwood, Flaws in the gianr impact hypothesis of lunar origin, I:arth Plall<t. Sti. Letl. 95, 208-214 (989). 31. G.]. Taylor, The scientific legacy of Apollo, Sti. Am. 2710),26-33 (1<)'14); C. Arthur, Moon is a chip off Earth's block, The lndepend,m (Land.) 28 July, 1 (1997);]. Heelll, The making of a Moon, Nel// Sci,mist 2 August, 8 (997); P. Bond, What size collision formed I he Moon', Astronomy NOI// 11(9), 5 (997);].]. Lissauer, It's not easy w make [he Moon, Natlir, (Land.) 389, 327-328 (1997); S. Ida, R. M. Canup, and G. R. Stewarr, Lunar accretion from an impa' (-generated disk, Natlire (Land.) 389, 353-357 (1997); D. -CO Lee, A. N. Halliday, G. A. Snyder, .Ind L. A. Turner, Age and origin of the Moon, Science (Wash., DC) 278, 1098-1103(997); P.
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