‘Post-truth era,’ ‘alternative facts,’ ‘misrepresentations.’ These are all colourful synonyms of what the unpolitical types call lies. At a time when truth has been so thoroughly molested, long-respected institutions questioned, the old ways of doing business suffering an ever-more critical gaze, it’s perhaps apt to exhale in relief as we reflect on some undeniable certainties. There really are some ideas that can’t be shaken. If they are, that would require a shift in our thinking so seismic it would be intolerable in the absence of a better, alternative idea.
Separate evidences lead to one conclusion
Scientists don’t cling to their theories for the sake of it or because they are fond of them. While it is true that scientists tend to nurture pet theories they want to shop around to colleagues and the scientific establishment—after all, they are as human as you and me and thus equally capable of self-delusion—the vast majority of them fall in line behind an established theory, not because of the profile of its originator but because it’s borne out by the evidence, over and over again.
There are numerous lines of evidence for the big bang theory (BBT), for example. Each, at different times, was independently arrived at. Moreover, the various evidences are locked into place by other well-established theories. This amounts less to a precarious house of cards or Jenga stack than an Egyptian pyramid. BBT almost must be true because if it isn’t, that would throw into question a host of other, separate scientific ideas we take for granted and for which there is overwhelming reason to believe in.
Here are some of the pillars of BBT:
- The abundance of light elements in the universe;
- The existence of cosmic microwave background radiation;
- The fact that galaxies are moving away from each other; and
- The fact that none of the stars observed are older than the universe.
Take the cosmic microwave background, the leftover heat from the big bang. BBT holds that the early universe was small, hot, dense and uniform. In 1964 a pair of scientists accidentally discovered this radiation and thought it was an anomaly in their observations due to faulty instruments. Almost forty years earlier Edwin Hubble discovered that galaxies were moving away from Earth at a certain increasing rate later called the Hubble constant. If galaxies are moving further apart, there must have been an earlier time when they were closer together, implying an ‘explosion’ or ‘bang’.
For these reasons and more, scientists are forced to confront the overwhelmingly likely scenario: the universe had a beginning, when it was smaller and hotter.
Even more telling of the power of established theories to explain natural phenomena, and unlike for many other sets of beliefs, there are very specific ways of showing that a theory is not correct or complete.
The anti-establishment rabbit
Just as there are various groups that seek to buck the system, whether it’s politics, culture or capitalism, so there is a rabbit out there that could bring down the entire edifice of a well-established theory. The elasticity of an argument, or ability to survive collision with any counterargument, is not a sign of its strength but rather its weakness. A good hypothesis makes a set of predictions against which it can be tested: if this hypothesis is true, expect to observe this thing or see this happen; if general relativity is true, expect to see a shift in the relative positions of stars near the sun at this time (indeed it was seen).
The elasticity of an argument, or ability to survive collision with any counterargument, is not a sign of its strength but rather its weakness.
For example, evidence against the theory of evolution would be the proverbial rabbit in the Precambrian era. The theory holds that diversity in the living kingdom arises due to a slow, gradual change over time. This implies that at a time Tm, there existed less complex organisms than at a later time Tn. So, we would not expect to find such a complex organism as a mammal in an era before the genetic line that gave rise to mammals existed in the first place, let alone multicellular life. Only far simpler creatures, like bacteria, abided on Earth then. Similarly, all it takes to throw out BBT is to find a star older than the universe itself, 13.8 billion years. No fossil evidence of rabbits in the Precambrian nor that of a star older than the universe have ever been found.
The danger of certainty
The 20th century, with all its wars and arrangements of society, has given us a vivid demonstration of what delusional certainty in particular sets of ideas can bring about. (A brief glance at Google News might indicate that those times are no longer in the rear-view mirror but clearly visible through the passenger window.)
Even in science there is not one thing that is known for sure. This is because there is a gap between the human mind and what we might call reality. That gap is filled by imperfect tools of measurement and the interpretive ability of the human senses; we use models to approximate reality, but never intimately know it. That is quite acceptable as long as we know the range of accuracy of our measuring tools and we use those tools for experiments that fall within that range. It can never be shown through DNA analysis that a certain older male is your father with 100% certainty, only 99.89% (I got news for you: he’s your father).
The scientific community, and everyone else, must check their confidence with the sobering appreciation of the limits of the human project of science. There are very many questions science cannot answer because they are either not well-defined, invoke ideas outside of nature or cannot be tested. This also applies to other areas of knowledge. In the words of the late Christopher Hitchens, in an age where information is flying thick and fast, and most us have neither the time nor expertise to weigh its merit, the correct posture is one of caution, hesitation and skepticism.
Feature image made by JBmemegeek with Imgflip Meme Generator
Inception screen grab copyright Warner Bros.