It takes a spe­cial kind of per­son to calm­ly debate those who pre­fer dog­ma to rea­son and who insist on ignor­ing or dis­tort­ing evi­dence to suit their pre­con­cep­tions. Carl Sagan was such a per­son. Among his many oth­er sci­en­tif­ic accom­plish­ments, he became leg­endary for his skill as an edu­ca­tor and sci­ence advo­cate. Sagan com­mu­ni­cat­ed not only his knowl­edge, but also his awe and won­der at the beau­ty and intri­ca­cy of the uni­verse, bring­ing to his expla­na­tions an unri­valed enthu­si­asm, clar­i­ty, and tal­ent for poet­ic expres­sion. And when faced with inter­locu­tors who were less than intel­lec­tu­al­ly hon­est, Sagan kept his cool and car­ried on.

This could be dif­fi­cult. In the audio from a radio call-in show above, we hear Sagan answer ques­tions from a caller with a clear, and rather fool­hardy agen­da: to best the astronomer, astro­physi­cist, and astro­bi­ol­o­gist in a debate over Dar­win­ian evo­lu­tion. He begins right away with some ad hominem, call­ing Sagan and his wife Ann Druyan “true believ­ers, who are no more will­ing to ques­tion the the­o­ry that you base your beliefs on than were the min­is­ters of the 19th cen­tu­ry who you reg­u­lar­ly crit­i­cize as being close-mind­ed.” The irony of accu­sa­tions like these should be obvi­ous. Though the caller doesn’t announce him­self as a cre­ation­ist, it’s abun­dant­ly clear to Sagan from his talk­ing points that he’s defend­ing a cre­ation­ist par­ty line.

Sagan attempts to answer his first ques­tion, but before he can fin­ish, the caller leaps to anoth­er bul­let point, the “gaps in the the­o­ry” or “gap­ing hole” of “fos­sils in tran­si­tion.” Sagan press­es his claim, with evi­dence, that “the Dar­win­ian con­cept of evo­lu­tion and nat­ur­al selec­tion is pro­found­ly ver­i­fied.” The insis­tent caller again inter­rupts and Sagan almost gives up on him, say­ing he “rather reminds me of Pon­tius Pilate. He asks, ‘what is truth?’ but does not stay for the answer.’” Then Sagan, with­out hes­i­ta­tion, patient­ly makes a case in brief:

Con­sid­er arti­fi­cial selec­tion. There is some­thing par­tic­u­lar­ly implau­si­ble about nat­ur­al selec­tion, par­tic­u­lar­ly if you think that the world is only a few thou­sand years old, as the Bib­li­cal chronol­o­gy would have it. Then the idea of one species flow­ing into anoth­er is absurd, we nev­er see that in our every­day life, we are told. But con­sid­er, for exam­ple, the vari­ety of dogs on the plan­et… We humans made them… by con­trol­ling which dogs shall mate with which…. In the short peri­od of 8 or 10,000 years, we pro­duce this immense vari­ety of dogs. Now com­pare that with four bil­lion years of bio­log­i­cal evo­lu­tion, not arti­fi­cial selec­tion, but nat­ur­al selec­tion, which goes into not just the over­all per­son­al­i­ty and char­ac­ter­is­tics of the dog, but the bio­chem­istry and inter­nal organs… and then it is clear that the beau­ty and diver­si­ty of life on earth can emerge. But if you don’t buy four bil­lion years, you don’t buy evo­lu­tion.

Sagan fre­quent­ly cit­ed this fig­ure of 4 bil­lion years for the ori­gin of life on Earth. Dur­ing his huge­ly pop­u­lar pro­gram Cos­mos, for exam­ple, he used the num­ber in an accel­er­at­ed evo­lu­tion­ary his­to­ry, which you can hear him nar­rate accom­pa­nied by a nifty ani­ma­tion in the video below. Most sci­en­tists have used that fig­ure or a few mil­lion years ear­li­er. For some time, the actu­al num­ber was thought to be between 3.6 and 3.8 bil­lion years. Recent­ly, as Tim Marcin reports at the Inter­na­tion­al Busi­ness Times, some sci­en­tists have con­clud­ed that “liv­ing organ­isms may have exist­ed on Earth as long as 4.1 bil­lion years ago.”

Marcin quotes UCLA pro­fes­sor of geo­chem­istry Mark Har­ri­son, who spec­u­lates, “life on Earth may have start­ed almost instan­ta­neous­ly” (rel­a­tive­ly speak­ing) after the planet’s for­ma­tion some 4.6 bil­lion years ago. These esti­mates come from car­bon dat­ing, not fos­sils, but just yes­ter­day, Sarah Kaplan writes at The Wash­ing­ton Post, dis­cov­er­ies of “tiny, tubu­lar struc­tures uncov­ered in ancient Cana­di­an rocks” may be evi­dence of ancient microbes thought to be 3.77 bil­lion years old, “mak­ing them the old­est fos­sils ever found.”

Like all new sci­en­tif­ic dis­cov­er­ies, these recent find­ings have been con­test­ed by oth­er sci­en­tists in these fields. And like some dis­cov­er­ies, their ques­tions may nev­er be resolved in our life­times. Sci­ence depends on meth­ods of data col­lec­tion, eval­u­a­tion and inter­pre­ta­tion of evi­dence, peer review, and many oth­er process­es sub­ject to human error. Sci­en­tists must often revise their con­clu­sions and recon­sid­er the­o­ries. No sci­en­tif­ic expla­na­tion is con­clu­sive­ly defin­i­tive in all its par­tic­u­lars. Nonethe­less, Sagan believed that only through the sci­en­tif­ic method could we obtain knowl­edge about the cos­mos and the ori­gin of life on earth that was in any way reli­able. He admired reli­gious ethics and the space reli­gions held for the big ques­tions. Sagan even declared in his 1985 Gif­ford Lec­tures (pub­lished posthu­mous­ly as The Vari­eties of Sci­en­tif­ic Expe­ri­ence) that “the objec­tives of reli­gion and sci­ence… are iden­ti­cal or very near­ly so.” But he did not think reli­gions could answer the ques­tions they asked.

Relat­ed Con­tent:

Carl Sagan Presents a Mini-Course on Earth, Mars & What’s Beyond Our Solar Sys­tem: For Kids and Adults (1977)

Carl Sagan Explains Evo­lu­tion in an Eight-Minute Ani­ma­tion

Watch Episode #2 of Neil deGrasse Tyson’s Cos­mos: Explains the Real­i­ty of Evo­lu­tion (US View­ers)

Carl Sagan, Stephen Hawk­ing & Arthur C. Clarke Dis­cuss God, the Uni­verse, and Every­thing Else

Josh Jones is a writer and musi­cian based in Durham, NC. Fol­low him at @jdmagness

Images via Wiki­me­dia Com­mons

In a 1997 essay in Nat­ur­al His­to­ry, Stephen Jay Gould (in)famously called the realms of reli­gion and sci­ence “Nonover­lap­ping Mag­is­te­ria”—a phrase that acknowl­edges both endeav­ors as equal­ly pow­er­ful and impor­tant to human life. His the­o­ry entails “respect­ful dis­course” and “con­stant input from both mag­is­te­ria toward the com­mon goal of wis­dom.” Many par­ti­sans then and now have found the idea hope­less­ly naïve or mis­guid­ed, and Gould did describe a rather specif­i­cal­ly enlight­ened exam­ple of the posi­tion: a per­son seek­ing “a more spir­i­tu­al view of nature” who also acknowl­edges “the fac­tu­al­i­ty of evo­lu­tion and oth­er phe­nom­e­na.” An edu­cat­ed skep­tic, with mys­ti­cal and poet­ic sen­si­bil­i­ties.

The major­i­ty of reli­gious believ­ers do not fit this descrip­tion. But some do. So too did Carl Sagan, to whom Gould ded­i­cat­ed his essay in a post­script. Sagan “shared my con­cern for fruit­ful coop­er­a­tion between the dif­fer­ent but vital realms of sci­ence and reli­gion.” How­ev­er, like Gould, Sagan gave the sci­en­tif­ic method the over­ride, and stren­u­ous­ly advo­cat­ed that we all do like­wise or become eas­i­ly duped by char­la­tans or by our own flawed per­cep­tions. Sagan acknowl­edged the cos­mos as a great mystery—one he want­ed to under­stand, not wor­ship. And he spoke of the nat­ur­al world with the kind of lyri­cal awe and rev­er­ence often reserved for the super­nat­ur­al.

Sagan, in fact, orga­nized and attend­ed the meet­ing at the Vat­i­can that occa­sioned Gould’s essay. He also found him­self, in the ear­ly 1990s, con­nect­ing deeply with anoth­er world reli­gious leader, the Dalai Lama. The exiled Tibetan Bud­dhist and the astro­physi­cist first met in Itha­ca in 1991, sit­ting down for the dis­cus­sion record­ed in the video above. Unfor­tu­nate­ly, the pro­duc­tion qual­i­ty ren­ders this record­ing near­ly unwatch­able. Their con­ver­sion is audi­ble but they both dis­ap­pear into a pix­e­lat­ed blue blur. That said, the con­ver­sa­tion mer­its preser­va­tion in any form (you can also read a tran­script of their talk here).

Sagan puts to the Dalai Lama the ques­tion he asked every major reli­gious leader he met with: “What hap­pens if the doc­trine of a religion—Buddhism let’s say—is con­tra­dict­ed by some find­ing, some discovery—in sci­ence, let’s say—what does a believ­er in Bud­dhism do in that case?” The answer below came very much as a sur­prise to Sagan, who lat­er said the Dalai Lama “replied as no tra­di­tion­al­ist or fun­da­men­tal­ist reli­gious lead­ers do.”

DL: ‘For Bud­dhists that is not a prob­lem. The Bud­dha him­self made clear that the impor­tant thing is your own inves­ti­ga­tion. You should know the real­i­ty, no mat­ter what the scrip­ture says. In case you find a contradiction—opposite of the scrip­tures’ explanation—you should rely on that find­ing, rather than scrip­ture.’

CS: ‘So, that is very much like sci­ence?’

DL: ‘Yes, that’s right. So I think that the basic Bud­dhist con­cept is that at the begin­ning it is worth­while or bet­ter to remain skep­ti­cal. Then car­ry out exper­i­ments through exter­nal means as well as inter­nal means. If through inves­ti­ga­tion things become clear and con­vinc­ing, then it is time to accept or believe. If, through sci­ence, there is proof that after death there is no con­ti­nu­ity of human mind, of life, then—theoretically speaking—Buddhists will have to accept that.’

Of course, many Bud­dhists may not find this sur­pris­ing at all. The prin­ci­ples the Dalai Lama out­lines are clear­ly out­lined in the Kala­ma Sut­ta, a sup­posed dis­course of the Bud­dha in which he issues a “Char­ter of Free Inquiry” as one inter­pre­ta­tion has it. It is indeed a unique fea­ture in world reli­gions, though the Dalai Lama did add—“mischievously,” said Sagan—that “it will be hard to dis­prove rein­car­na­tion!” In such areas where a propo­si­tion can­not be fal­si­fied, reli­gion and sci­ence may agree to disagree—civilly or otherwise—or change the sub­ject. In the course of their acquain­tance, Sagan and the Dalai Lama dis­agreed on very lit­tle.

When it comes to Bud­dhism, the Dalai Lama points out that the con­ver­sa­tion between sci­ence and reli­gion is hard­ly one-sided: “Some sci­en­tists also show a gen­uine and keen inter­est in Bud­dhist expla­na­tions…. One thing is quite clear: As far as men­tal sci­ences are con­cerned, Bud­dhism is very high­ly advanced.” The inter­est researchers and neu­ro­sci­en­tists have shown in Bud­dhist psy­chol­o­gy and med­i­ta­tive ther­a­py has only increased in the past twen­ty-five years, such that entire depart­ments devot­ed to mind­ful­ness med­i­ta­tion have sprung up at ven­er­a­ble uni­ver­si­ties and respect­ed med­ical schools.

And since Sagan’s death in 1996, the Dalai Lama has con­tin­ued to reflect on the con­ver­gences between sci­en­tif­ic dis­cov­ery and Bud­dhism in his books and talks. And Sagan’s wid­ow Ann Druyan has car­ried on Sagan’s lega­cy, shar­ing the awe and won­der of sci­ence with a pop­u­lar audi­ence through film, print, and tele­vi­sion. In 2007, Druyan appeared at Cor­nell to talk about the affini­ties between Sagan and the Dalai Lama dur­ing their first and sub­se­quent meet­ings. You can see her talk in full here.

Relat­ed Con­tent:

Carl Sagan Presents His “Baloney Detec­tion Kit”: 8 Tools for Skep­ti­cal Think­ing

Carl Sagan Issues a Chill­ing Warn­ing to Amer­i­ca in His Final Inter­view (1996)

The Dalai Lama on the Neu­ro­science of Com­pas­sion

Josh Jones is a writer and musi­cian based in Durham, NC. Fol­low him at @jdmagness