A friend of mine asked me, the other day, whether I was worried about the impending gravitational effect of the alignment between the Sun and the supermassive black hole at the center of our galaxy (known as Sagittarius A*) – creating havoc on Earth.
Some believers in a 21st December 2012 doomsday have used the term “galactic alignment” to describe a pattern in mass extinctions supposedly recurring every 26 million years or so. To account for this, it suggests that vertical oscillations made by the Sun on its 250-million-year orbit of the galactic center cause it to regularly pass through the galactic plane which might increase the flux of Oort cloud comets into the inner Solar System by a factor of 4, thus leading to an increase in the likelihood of a devastating comet impact.
Another idea tied to 2012 involves geomagnetic reversals, which recently happened every 100’000 years or so. Most scientific estimates say that geomagnetic reversals take between 1,000 and 10,000 years to complete, and do not start on any particular date. Nor is it clear that the phenomenon has any untoward effects on life on earth.
Granted, there is increasing evidence that what happens inside the earth’s core has influence on life on the earth’s surface, but to extend the causal chain to stellar alignments seems, on the face of current knowledge – well, let’s say: far-fetched.
Why the preponderance of such beliefs? The operative analogy is the term “alignment”. Astrologers saw portents in starry alignments. We know that the alignment of sun, moon, and earth can create high tides, which can be destructive. “Alignments” of any sort are ominous – and plausible. They speak to our emotions. Intuitively the analogy makes us feel “(un)cuddly” in this event. We are “true believers” if not believers in truth.
One notable result of the SCOTT expedition to the Antarctic were fossils of broad-leafed trees the unlucky explorers had found and loaded on the last sled they were hauling as they tried to reach “One-Ton Depot”. For about one hundred years the conventional scientific wisdom was that ancient forests growing in Polar Regions were deciduous: shedding leaves prior to the inset of polar darkness avoided carbon losses at a time when they could not photosynthesize in the darkness of warm polar winters. No leaves, no loss – how plausible.
Except – no one had bothered to check the facts. “Passed down through the literature from one generation to the next, the idea has an allegiance closer to a religious belief than a scientific theory.” (pg. 131) It was left to two enterprising women-botanists to do the quantitative analysis that upset the “cuddly” analogy. The current explanation is much more subtle, complex, and fascinating.
We all use analogies – they are a first shot in the dark at understanding a problem in Bayesian fashion, ki.e. by trail and error. Like the starting pistol shot, they should stimulate our critical thinking and soon lead us to paradox: “How wonderful that we have met with a paradox. Now we have hope of making progress” (Niels BOHR). After that scientific endeavor advances, crab-like, through the iterative process of conjecture and refutation. Analogies achieving this kind of trajectory are great.
Alas, analogies can lead to laziness instead – we accept the “plausible” explanation without checking and apply it unthinkingly. It hardens into received wisdom. Personalities become involved – reputations are at stake. The greatest enemy of truth is what “seems” like truth.
Spurious analogies from diplomacy
The “domino theory”, which underlay much of the West reaction to Communism, is one. Laos, and then Vietnam come to mind. It was “the lazy man’s analogy” replacing analysis of complex social and political dynamics as third world countries integrated into the global scene. Over 50’000 Americans gave their lives to atone this intellectual laziness.
‘As Calais was written on Queen Mary’s heart,’ Nehru told a British general in a revealing comparison, ‘so Kashmir is written on mine.’ What utter nonsense – and the wrong metaphor to boot, for Queen Mary lost Calais, while Nehru hung on to Kashmir.
The greatest danger of analogy, to me, is taking the image for the real thing. An ambassador “represents” his country – fine. An offence to an ambassador is then equated to offending the country – even though the “slight” to the diplomat may have been deserved in the specific circumstances. This is already a dubious extension of the analogy. By slow expansion of the analogy ambassadors’ spouses are taken in chauffeur driven cars to shop downtown and the privilege of not paying parking fines is affirmed. Analogy has degenerated into unassailable, unthinking ritual. Diplomacy is awash with rituals – etiquette.
Beware of rituals – they are analogies made flesh.
 This kind of “galactic alignment” already happened in 1998. The Sun’s apparent path through the zodiac as seen from Earth, however, does not take it near the true galactic center, but rather several degrees above it. In any case, Sagittarius A* is 30,000 light years from Earth, and would have to be more than 6 million times closer to cause any gravitational disruption to Earth’s Solar System.
 See e.g. Clive OPPENHEIMER (2011): Eruptions that shook the world. Cambridge University Press, Cambridge.
 David BEERLING (2006): The emerald planet. How plants changed earth’s history. Oxford University Press, Oxford.
 Warfare is another area where analogies are “deadly friends”. Incompetent generals are not removed on grounds that it would represent “loss of face” for the country at war. See e.g. Rick ATKINSON (2002): An army at dawn. The war in North Africa, 1942 – 1943. H. Holt, New York.
 “Climate change” yields the latest avatar of the “domino theory”: The BBC commentator Jack Fortune was heard to utter this prophecy in 2005: “Earth’s climate would be spinning out of control, heading towards temperatures unseen in four billion years.” See BEERLING op. cit. pg. 210.
 See e. g. Seth JACOBS (2012): The Universe Unraveling: American Foreign Policy in Cold War Laos. Cornell University Press. Ithaca.
 Perry ANDERSON (2012): After Nehru. London Review of Books, Vol. 34, 15.
 I’ll freely admit to a jaundiced view of “diplomatic privileges are immunities”. Their original pragmatic character has long since drown is self-serving ritual.