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This essay was completed early in April of 1976, for inclusion in the A.A.A.S.-Cornell volume Scientists Confront Velikovsky, and it is to the latter that such expressions as “this volume” refer. After writing the “Afterword” in accordance with the limitations of space and time laid down by the A.A.A.S.-Cornell people, Velikovsky decided that he would not participate any further in their volume, because of their unfair and restrictive requirements, and because of their long record of broken promises and rigged arrangements. -The Eds. ]

It has been claimed in print that I “objected” to efforts “to publish the proceedings” of the Symposium (Owen Gingerich, “Science Year Close-Up” , World Book Encyclopedia Supplement, 1975, page 249), and also that at the Symposium “Velikovsky was clearly shown in error, which perhaps explains why he has seen fit to prevent the publication of the transcript of the meeting” (Reader's Forum, Mercury: Journal of the Astronomical Society of the Pacific, November/December, 1975, page 35).

None of this is true.

The tape recording of the Symposium shows that I effectively and forcefully answered my opponents. I have urged, since even before the Symposium was held, that the papers as delivered and the discussions as spoken should be quickly published, with minimal editing, or, better, with no editing at all, so that there would be a full and accurate historical record of what transpired. This record could have been supplemented by additional papers by each of the panelists, but any such new material should have been clearly designated as supplementary to the historical record of what was said on February 25, 1974.

This plan was not accepted, however, and it was decided by others that Professor Carl Sagan, one of the panelists at the Symposium, could revise his paper prior to publication. My own paper was intended to be printed exactly in the form in which it was distributed on February 25,1974. Hence the delay in the preparation of materials for this volume has not been due to me, despite what Gingerich and others are saying. The principal delay in the preparation of material for this volume has been due to Sagan, who consumed nearly two years (late February 1974 to early February 1976) in revising and greatly expanding his paper. There are well over thirty pages of new material in the 1976 paper, I could not be expected to have prepared answers to additional arguments and assertions that I had never even seen until February 1976.

By the decree of the organizers of this volume, I am limited to six thousand words or about twenty typewritten pages to answer the papers of the panelists at the Symposium that was held on my work. I found such a limitation unfair, but I agreed, lest my rejection be branded as a refusal to meet my opponents on printed pages.

To “equalize,” each of the other panelists is offered three thousand words to add his counterarguments. The reader will excuse me if I do not answer these counterarguments here: I will not be permitted to see them before the volume is printed.

I will omit here the story of how the Symposium came to be; but the original offer to have equal numbers of panelists on opposing sides was not carried out; the chairman, having come under pressure from the higher echelons of the establishment for the very idea, wished to publish an advance statement, making known that no pursuit of scientific debate was really in mind, and he also made an opening statement at the Symposium itself on that score, thus subscribing to a bias in advance of the debate. With a biased chairman, with an unbalanced panel, and with the papers of those panelists attacking my theories not sent to me in advance of the seven-hour debate, I, in the opinion of the fourteen hundred in the audience, fared well — as indicated by the standing ovation that was accorded only to the iconoclast. But the scientific and semi-scientific press showed by its reports that it was orchestrated - the very sentences, and the very same errors of fact and number, appeared simultaneously in many reviews.

The press in a chorus singled out and repeated the “overkill” by Sagan in his paper of 57 typewritten pages. In the oral confrontation at the morning session he read only part of his paper; it was anything but an overkill — and the audience reacted accordingly. The organizers permitted him to work on his paper for two additional years, and what appears in this volume has grown to 87 typewritten pages submitted in February 1976 as a paper read in February 1974. This, too, I protested, but I decided that any strictures and retreats from an unbiased position, to which they were obligated, will, in the final count, not serve their interest, which is to do what the previous generation could not — to stamp out the heresy, by stampeding the media.

A careless reader of the papers of the panelists will come away with the feeling that the basic tenets of my work have been pulled apart. The careful reader, however, will observe that my opponents retreated on all major fronts, and even surrendered the cherished arguments that were much used in the past and also used even more recently against my work. In this itself is a measure of victory.


Two astronomers confronted me on the panel: Professor J. Derral Mulholland, whose field is celestial mechanics, and Professor Sagan, whose field is planetary atmospheres, rock compositions, and biological conditions. Mulholland said:

... the celestial mechanics of Newton and Newcomb are no longer the ultimate measure. The celestial mechanics of 1974 is a living, vital science that admits of non-gravitational effects, of electromagnetic interactions. . . .

This is a retreat of unprecedented significance. My opponents of the 1950's would not permit the smallest concession regarding their dictum that only gravitation and inertia account for celestial motions. They put themselves on record in print.

Celestial near-collisions could have happened, according to Mulholland, who here sheds the uniformitarian dogmas. Giant tides, global earthquakes, changes of the direction of the celestial axis would have resulted. “There is no faith here; these are unavoidable consequences of the laws of motion” .

But whether all this happened depends on historical and archeo-logical evidence that can be presented. He criticizes a few single cases like the case of Babylon that in the past changed its position in relation to the pole by several degrees. But my sources were Johann Kepler, who quotes Arabian geographers, and historians going back to Ptolemy. Every other change, like the changing ratio of the shortest to the longest day in Babylon and Egypt, I also discussed in some detail.

Mulholland asks: “Does Velikovsky's evidence provide reasonable proof that the axis shifted abruptly and catastrophically 27 centuries ago?” His verdict is in two words: “Absolutely not” .

No careful reader of Worlds in Collision would agree. All of the evidence from Greek, Roman, Babylonian, Sumerian, Chinese, Hindu, Hebrew, Egyptian, Mayan, and Toltec civilizations are dismissed in this casual fashion, hundreds of pages, thousands of references. There are also several chapters in Earth in Upheaval dealing with evidence of the changing position of the terrestrial axis.

Mulholland, who on the first page of his paper refers to how both Venus and Mars “erupted into the sky” as “two giant comets” , cannot be counted among careful readers. He did not refer to Earth in Upheaval; and all the evidence from deserts, polar lands, jungles, once habitable countries, are also disposed of in this two-word verdict, though he agrees and stresses that “if a planet-sized object were to pass close by the Earth” , the consequences would be the very events described in Worlds in Collision.

I thank Mulholland for saying “Velikovsky's challenge is not one to be decided on a basis of belief or unbelief.” Mulholland continues:

He strives to build physically plausible solutions that involve testable ideas. He is not a mystic.” — and this when some prominent scientists announced that I belong in one group with palmists, astrologers, or believers in a flat earth. But when Mulholland says that the rotation of Mars refutes the theory of recent catastrophism, he has grasped a weak reed — is it not agreed that Mars lost a major portion of its rotational angular momentum?


Professor Norman Storer was selected by the organizers of the Symposium to represent the sociological aspect of the Velikovsky controversy. He concluded that it would be a sign of objectivity to divide equally between myself and the establishment the guilt for what happened. Storer made the fundamental error of confusing neutrality with objectivity, and his efforts failed, as I pointed out in the evening discussion: one who maintains “neutrality” between a gross offender and the victim of the offense does not give an objective account of the realities; the account is biased in favor of the offender. Storer's paper is a whitewash of the offenses of the establishment.

Storer's was the only paper sent to me before the Symposium.


Dr. Peter Huber is a professor of statistics (on the program he was billed as a professor of ancient history), his Assyriology being, as he told me, his hobby. Huber tried to bring out of one or two sources of ancient material 1) that the solar system was stable through historical times (since a certain solar eclipse could prove it), and 2) that Venus was observed in the sky earlier than the first near encounter of the protoplanet Venus with the Earth.

To the first point it would suffice to cite the opening paragraph of van der Waerden's article of 1951 (Journal of Near Eastern Studies, vol. X, p. 20). In the Assy ro-Baby Ionian calendar of about -700 the vernal equinox was transferred by more than a month. Also the ratio of the day to the night at the summer solstice seems to have changed from 2:1 to 3:2. Similar changes took place in Egypt at the same time.

And of what value are reports of phenomena from Syria or the Far East that are now supposed to be eclipses, when a plurality of scholars long acquainted with the problem discount such claims or interpretations? In my debate with Princeton astronomer John Q. Stewart, in Harper's, June 1951, Stewart based himself on an article by Fotheringham concerning three historical “eclipses” . In 1974 Huber declared me right, and Fotheringham followed by Stewart he declared wrong.

As to whether Venus had been seen before -1450, Huber refers to the so-called Ammizaduga tablets (Schiaparelli refers them not to Ammizaduga but to the seventh century). But Huber needed to announce that in about thirty percent of readings the text has to be changed: east must be changed to west, and west to east; the names of months must be changed; the dates of the month must be changed; the intervals between disappearance and reappearance of Venus must be lengthened or shortened — all in order to prove his point that Venus moved then as it moves now. My own understanding of the Venus tablets does not require a thirty percent change of data — probably not even one datum — and the tablets show only that Venus did not travel on the orbit it travels now. (See Worlds in Collision, p. 198 ff.)

Huber also quotes a Sumerian text (its being in Sumerian does not attest its antiquity; like Latin, Sumerian was used for sacerdotal purposes for many centuries after the Sumerian civilization went down in destruction, leaving hymns and prayers to the feared planetary gods); and Venus in the text quoted by Huber is compared in its brilliance to the Sun itself.

What is more: in an earlier prepared review, to explain a series of facts otherwise unexplainable, Huber expressed the surmise that the solar system may have been visited or invaded by a new planet that caused havoc in nature and awe in man: “highly improbable, but not to be excluded capture of a rather large foreign heavenly body into the solar system in historical time. . . .” (My italics.)


As my opponent for the fourth tournament, the astronomical establishment selected Sagan. To answer his nearly 90 pages and nearly 30,000 words (1976 version), I am left with barely one-tenth of that amount, though an answer usually requires more space than an accusation, especially those that are bland and unsupported: I must first state what the charge was, then state what the truth is, what I really wrote, etc., and then present the evidence for what I said. In the 1974 version of his paper, Sagan had twice mentioned both the letter of Bargmann and Motz and the letter of Hess, but in the 1976 version all such references have been deleted, even from the Bibliography. These deletions cannot have been in the interest of saving space, for Sagan allowed the length of his paper to grow by more than fifty percent. In their letter published in Science (December 21, 1962), Professor V. Bargmann, Department of Physics, Princeton University, and Professor Lloyd Motz, Department of Astronomy, Columbia University, called attention to the originality and to the correctness of my predictions of radio noises from Jupiter and of a very high temperature of Venus (they also mentioned my prediction of the existence of the terrestrial magnetosphere). Bargmann and Motz conclude: “Although we disagree with Velikovsky's theories, we feel impelled to make this statement to establish Velikovsky's priority of prediction of these two points and to urge, in view of these prognostications, that his other conclusions be objectively re-examined.” In his open letter to me on March 15, 1963, Professor H. H. Hess, Chairman of the Geology Department, Princeton University, wrote: “You have after all predicted that Jupiter would be a source of radio noise, that Venus would have a high surface temperature, that the sun and bodies of the solar system would have large electrical charges and several other such predictions. Some of these predictions were said to be impossible when you made them. All of them were predicted long before proof that they were correct came to hand. Conversely, I do not know of any specific prediction you made that has since been proven to be false.” The deletion of his earlier references to Bargmann and Motz and to Hess seems to be a part of Sagan's program to deny me credit for my record of correctness and originality.

In the two years during which his paper was brought into shape, Sagan was helped by such authorities as Thomas Gold and Philip Morrison among others, and therefore I am in the position of standing against the entire establishment, though greatly limited as to space and time, and blindfolded as to any additional counterarguments my opponents may bring, before I see the printed book. Unjust as such conditions may be for a scientific debate, I am not abandoning the project and will do my best under the circumstances, to the limits of what decency can tolerate, though my friends, also in positions of moral standing in the community of the scholarly world, advised me to abandon the project and if necessary give a complete and unbiased account with the help of several collaborators.

Sagan may mislead the reader by professing, in opening his paper, high principles and even magnanimity (benefit of doubt going to me); he declares also that no physical laws are inviolate if facts of experience or of experiment oppose them - by this echoing the words in the Preface of Worlds in Collision. He actually admits that all vituperations of his guild in the past 26 years were not supported by sound argument. Sagan concludes that a planet could have escaped from Jupiter; that a disturbance of rotation of the Earth could have happened; that the terrestrial axis could have changed its direction;

that a bringing of the Earth to a rotational stasis even in less than one hour, would hardly be noticed by human beings and they certainly would not fly off into space (what he himself asserted a few years ago and what his friend Asimov still asserts); nor even would stalactites break off (Asimov's foremost argument till today).

Sagan makes more fundamental concessions; and above all, agrees that changes in the order of the solar system could and must have taken place. This last general statement was the only thing I communicated to Harlow Shapley that started the campaign of suppression which is not over even today.

All these basic statements were used by the generation of Shapley and Payne-Gaposchkin against my work. Sagan also is contemptuous of 25 years (1950-1975) argumentation of his guild: “I am surprised at how little of it there is.” “There is nothing absurd in the possibility of cosmic collisions.” “Collisions and catastrophism are part and parcel of modem astronomy” — and so already for centuries. There is nothing unorthodox about the idea of cosmic catastrophes, says Sagan. Then why was I, and my work, vilified for a quarter of a century?

Fortresses having been surrendered, makeshift fortifications are being raised. “What then is all the furor about?” — It is the time scale and the written ancient evidence. Sagan admits “I find the concatenation of legends which Velikovsky has accumulated stunning. . . .” From here starts the assault. Sagan follows me into many areas and cuts many Gordian knots.

Throughout his paper, Sagan repeatedly stresses that I accept some parts of ancient myths and legends and not other parts, and he wonders why I do not accept either all or else nothing. He suggests that my procedure here is arbitrary or capricious. But Sagan has not troubled to understand my procedure. He complains that I accept ancient legends about manna, but that I do not accept the scriptural account that manna fell in a double portion on Fridays and not at all on Saturdays. But I accept the ancient testimonies about manna of the Hebrews, ambrosia of the Greeks, and honey-dew of other peoples from around the Earth, precisely because there is testimony on this from many peoples from many parts of the Earth and because there are physical events (the near collisions between Earth and Venus) that could have led to such results. And I reject the report about manna falling in double portions on Fridays and not at all on Saturdays, precisely because that feature of the story does not have a plausible physical basis, is not testified to by other peoples, and is therefore to be regarded as an inaccurate elaboration by one people upon what actually transpired.

Whoever read the sections in Worlds in Collision on ancient calendars and calendar reforms occurring from Japan to India, to Persia, to Assyria and Babylonia, to Greece, to Rome, to Israel, to Egypt, and so on, would not have been misled by the simplistic theory that 360-day years were merely convenient approximations.

Sagan moves to cave paintings (where he finds only a picture of a supernova) and to ancient art generally and asks: “If the Velikovskian catastrophes occurred, why are there no contemporary graphic records of them?” As a novice in the field, Sagan should perceive that the great majority of ancient contemporary art is dominated by the theme of global catastrophes and celestial planetary deities in battle. In my lecture I referred to the Mayan, Olmec, and Toltec art — and whoever visits Yucatan knows that virtually no other theme exists in this art. No dynastic or military exploits, but battles between planetary deities, and sacrifices to them — almost to the exclusion of other themes. The cave man pictures animals in global conflict; serpents fighting planets are a frequent theme in cave and mural art; and in literary art — from the Iliad, to the Assyrian prayers, to the Old Testament, its prophets and psalms, to Hindi and to Icelandic epics — it is the all-pervading motif. So it goes in this domain, which is foreign to Sagan.

Sagan writes:

Other critical statements which are given extremely inadequate justification, and which are central to one or more of Velikovsky’s major themes, are as follows: the statement (page 283) that ‘Meteorites, when entering the earth's atmosphere, make a frightful din,' when they are generally observed to be silent; the statement (page 114) that 'a thunderbolt, when striking a magnet, reverses the poles of the magnet;' the translation (page 51) of ‘Barad’ as meteorites; and the contention (page 85) ‘as is known, Pallas was another name for Typhon.’ On page 179 is enunciated a principle that when two gods are hyphenated in a joint name, it indicates an attribute of a celestial body — as, for example, Ashteroth-Kamaim, a homed Venus, which Velikovsky interprets as a crescent Venus and evidence that Venus was once close enough to the Earth to have its phases discernible to the naked eye. But what does this principle imply, for example, for the god Ammon-Ra? Did the Egyptians see the sun (Ra) as a ram (Ammon)?

The Smithsonian Institution published in 1929 a volume on Minerals from Earth and Sky. George P. Merrill, Head Curator, Department of Geology, U. S. National Museum, contributed “The Story of Meteorites,” in which he gives a long series of reports of loud explosions accompanying the fall of meteorites. Meteorites are a subject that belongs to Sagan's own field, but he does not know that they can make noise. For example, in Emmet County, Iowa, on May 10, 1879: “The sounds produced by the explosions incidental to its [the meteor’s] breaking up were referred to as terrible and indescribable. . . . The first explosion, for there were several, was louder than the loudest artillery.” This is only one of a number of illustrative cases described by the Smithsonian Institution. So silent when entering the atmosphere they are not, Sagan notwithstanding.

Sagan wonders that “a thunderbolt, when striking a magnet, reverses the poles of the magnet” . This explains the reversals in paleomagnetism (Worlds in Collision, pages 114-115). If Sagan has doubts, let him perform an experiment.

The word barad, being described as hot, could not be ice hail, but is properly interpreted by me as meteorite.

That Pallas and Typhon are the same I need not have supported with a note — any dictionary will tell this.

Ashteroth-Kamaim is mentioned on page 169 of Worlds in Collision. Neither there nor anywhere else in my writings, have I ever said that whenever there is a hyphenated pair of names for a deity, this “indicates an attribute of a celestial body” . The “principle” is Sagan's invention. Sagan asks — in connection with Ammon — did the Egyptians see the Sun as a ram? Yet Ammon was not the Sun, but, as is known from many sources, Ammon was the planet Jupiter. (Herodotos, 11:41)

Sagan next presents “Velikovsky's Principal Hypothesis” , and he purports faithfully to tell what it is. I will follow this for two or three pages, and the reader will have enough. Sagan says: “at the moment that Moses strikes his staff upon the rock, the Red Sea parts. . . .” Later, “after the death of Moses ... the same comet comes screeching back for another grazing collision with the earth. At the moment when Joshua says “Sun, stand thou still upon Gibeon; and thou Moon, in the valley of Agalon,” the Earth . . . obligingly ceases its rotation. ...” He later says that I “attempt to rescue the old-time religion” . To tell of Velikovsky's principal hypothesis in this vein is nothing but purposely misleading.

In the story of the crossing at the Sea of Passage, I deliberately did not even mention Moses; and some 200 pages later (in the section, “The Subjective Interpretation of the Events and Their Authenticity” ) I wrote: “The sea was torn apart. The people attributed this act to the intervention of their leader; he lifted his staff over the waters and they divided. Of course, there is no person who can do this, and no staff with which it can be done. Likewise in the case of Joshua who commanded the sun and the moon to halt in their movements. Because the scientific mind cannot believe that a man can make the sun and moon to stand still, it disbelieves also the alleged event.” (Worlds in Collision pages 306-307.)

In the Biblical story, Moses did not hit the rock with his rod at the Sea of Passage; the striking of the rod against the rock is from the story (not quoted by me) of finding water in the desert. Biblical scholarship is not Sagan's field. And I stressed that many Israelites did not succeed in crossing the Sea, and the large majority of them perished (according to Psalms and midrashic sources, actually 49 out of 50 during the Plague of Darkness), contrary to the account by Sagan of my “hypothesis.”

These are just examples of Sagan retelling my book. One of the major areas of disagreement between Sagan and myself has to do with the composition of the atmosphere of Venus. This was perhaps the principal topic of discussion at the Symposium, and it is my understanding that the organizers of this volume will be including a complete and accurate transcript of that discussion. The readers of such a transcript will see for themselves how I have already replied, both during the morning session and during the evening session, to Sagan’s claims. Thus I will not explore this subject further here.

Among many other disputes that I have insufficient space to discuss are: orbital circularization; escape velocities from Jupiter; and rotational stasis as opposed to axial tilting. I have answers regarding these and other issues, but the publication of those answers will have to be in some other context where there is not such a severe limitation on space. The reader is also directed to my published writings, wherein are already contained the answers to all of Sagan’s various arguments and assertions, if he had but troubled to look.

But there are two matters that must be dealt with before I close:

Sagan’s denial of the originality of my advance claim regarding the heat of Venus, and his widely publicized calculation of the “odds” against my theory's being true.

Sagan repeatedly states that none of my advance claims was original and correct. He made this announcement in the press before the Symposium, but as an organizer and panelist he should not have prejudiced the outcome. He says that Rupert Wildt in 1940 already proposed that Venus under the clouds is hot, and that I presented my claim of the heat of Venus without telling of Wildt and Wildt's estimate. (Actually, I did not give anyone's estimates.) So what was Wildt's estimate, and upon what was it based? He was the originator of the greenhouse effect theory that would keep Venus hot, and he came to the conclusion that only the subsolar point of the surface of Venus is of the temperature of boiling water, or possibly up to 135 degrees Centigrade. Professor G. Kuiper later showed that Wildt erred in his evaluation of the albedo or reflecting power of the Venus clouds, and therefore the temperature because of the greenhouse effect would be definitely less.

In Worlds in Collision, I stated that the protoplanet Venus “was in a state of candescence” only a few millennia ago, and I enumerated my reasons:

Venus experienced in quick succession its birth and expulsion under violent conditions; an existence as a comet on an ellipse which approached the sun closely; two encounters with the earth accompanied by discharges of potentials between these two bodies and with a thermal effect caused by conversion of momentum into heat; a number of contacts with Mars, and probably also with Jupiter. Since all this happened between the third and first millennia before the present era, the core of the planet Venus must still be hot.

I proposed that “Venus is hot”; that the source of the heat is Venus itself, rather than the sun; and that the temperatures are high enough for hydrocarbons to “circulate in gaseous form” and for the planet to have been “in a state of candescence” only a few thousand years ago, which means that the temperatures would be hundreds of degrees higher than Wildt or anyone else had ever imagined. Wildt's greenhouse effect theory was not relevant to my theory, and there was no reason why I should have cited him.

What I did cite in Worlds in Collision was the literature on the thermal balance of Venus. Thus the temperature of the clouds was found to be nearly the same (actually, about -25 C.), both for the day side and for the night side. This was paradoxical, since spectral indications were that Venus rotated very slowly. (This was later confirmed by radar studies.) Why did the night side not cool off? My answer was that the heat of the clouds of Venus, both on the night side and on the day side, is from the planet itself, not from the sun. I said: “Venus gives off heat.” Later, in a paper entitled “Is Venus' Heat Decreasing?” I called attention to separate measurements, spread over a number of years, in which the temperatures for the cloud surfaces seemed to be decreasing. Indeed, from these results only one deduction can be drawn: Venus cools off. Despite my repeated challenge to institute a planned observation of the rate of this cooling off, I have seen no paper dealing with the problem as it deserves — with a full cognition of what deductions are to be made if Venus is really cooling off. But even from an unplanned, haphazard comparison of figures, the trend can be recognized — and the lowering of the cloud surface temperature reflects an even greater lowering of the ground surface temperature of the planet.

Venus gives off heat,” as I wrote in Worlds in Collision. In other words, it sends off more heat than it receives from the sun; it is in a state of thermal imbalance. If it has traveled on its orbit for billions of years and all the time has been cooling off, staggering figures would result for a time a million years ago, and unnatural figures for a time measured in billions of years. If in the fifty years since the observations of Pettit and Nicholson in the 1920's, the cloud surface lost, say, 8° C., a simple arithmetical deduction would point to a loss of 1° C. in 6 years, which would represent a substantially greater loss on the ground, under the cloud cover and the lower atmosphere. I assume that calculation would show that the planet must have been largely incandescent only thirty-four centuries ago.* Such research would lead to the result that Venus is a newcomer (what its name in Latin also means).

The grace with which the figures of various observers, through decades, were left without being tabulated is a psychological phenomenon - the preference “not to know,” if the knowledge threatens to convey a firm basis to an iconoclastic concept.

Sagan calculated that a chance of one against 30,000 was needed in order to make Venus hit the Earth in any given millennium, and to produce a series of collisions the chance is one against 1027, if such collisions are statistically “independent” . The problem of marksmanship was discussed by me in my debate with the late Professor John Q. Stewart, Princeton University astronomer (Harper's, June, 1951, page 64). I came to a completely different result:

The image of ‘marksmanship’ is not well derived. The planets revolve in the plane of the ecliptic; if one should move on a stretched orbit, it would contact its neighbor planets. And if a comet with a tail 100 million miles long [actually, it is not excluded that the tail might be even several hundred million miles long] should move in the ecliptic, no good fortune would keep the [inner] planets from passing through its fabric; at its every passage inside the terrestrial orbit, the Earth would have a better than 60 to 40 chance of going through its tail or head.”

In his calculations, Sagan chops off the tail of Venus that sweeps the entire area, and assumes that “Velikovsky is talking about a grazing collision: the surfaces of Earth and Venus scrape!” But in my writings it is repeatedly emphasized that these near collisions were not “grazing” collisions: the “targets” were larger, by many orders of magnitude, than Sagan allows. On page 85 I said that “the head of the comet did not crash into the earth,” and on page 372 I said that planets, during a close approach to each other, are “cushioned in the magnetic fields around them ... an actual crushing collision of the lithospheres will be avoided.”

Sagan calculates how close the head of the comet Venus must have come to the surface of the Earth, on the assumption that tides 1600 miles high were raised. On page 72, I quoted a midrashic source: “The waters were piled up to the height of sixteen hundred miles, and they could be seen by all the nations of the earth.” In the very next sentence I indicated that this legend obviously is not to be taken literally: “The figure in this sentence intends to say that the heap of water was tremendous.” But Sagan, in search of bizarre premises from which to derive bizarre conclusions, takes the figure of 1600 miles literally, and bases his calculations upon it. The figures in his conclusions should not be taken any more seriously than the figures in his premises.

Sagan further assumes “that Velikovsky believes in several statistically independent collisions in a few hundred years” , despite my many explicit statements that the collisions were causally interrelated. For example, see Worlds in Collision, page 373; “Each collision between two planets in the past caused a series of subsequent collisions.” A ten-car pile-up on the expressway is a chain reaction: it does not consist of ten independent events. Sagan's inferences are unsound. He should know better than to apply to causally interrelated events laws of probability that are appropriate only for independent events.

In general, when we are speaking of the probability of historical events, we must proceed with great care and caution. Whether something did or did not occur must be decided on the basis of historical evidence, not on the basis of probability laws. Actually, if some historical event is described with great precision, and each characteristic of that event is treated as an independent factor, then the probability of such an event will be vanishingly small. If all the details of an automobile collision are listed, then the probability that such an event could occur will be so low as to seem almost impossible. Yet collisions of automobiles have indeed occurred — and so have near collisions of planets.


*Such a calculation was actually made by physicist C. J. Ransom in 1972. The results obtained by Dr. Ransom indicate that the temperature of Venus 3500 years ago would be 1184° K - or fully incandescent (Pensée II, Fall, 1972, p. 18).