Banana lovers around the world are in peril of losing their favorite topping for cereal and sundaes. Nearly all bananas sold on the international market are of one variety, Cavendish, which reproduces through cloning rather than sexually and therefore lacks genetic diversity. A fungus known as Panama disease threatens to wipe out the entire crop. Cavendish monoculture has produced a fruit that tastes good, transports well and ripens predictably—perfect for a particular moment and market niche. But as soon as things change—in this case, as Panama disease spreads—the advantages of monoculture quickly become vulnerabilities.
Something similar happens in the intellectual realm. Ideas that seem suited to a particular moment and set of circumstances can take hold and marginalize contradictory thought. All right-minded people cannot help but be persuaded. To question the orthodoxy brands the questioner a heretic. In what they perceive as their enlightened self-interest, societies cast out the heretics and make them pariahs.
But then things change. New evidence appears or new circumstances arise. What had suited the previous era fails to fit the new situation. In the banana world, hope rests with the tiny proportion of bananas that aren’t Cavendish and that survived in small niches in various parts of the world. The intellectual equivalent is heretical ideas that were not quite snuffed out.
For centuries the idea that continents could move around on the surface of the Earth seemed inane to most geologists. How could something as massive as a continent move? The apparent fit of the western coastlines of Europe and Africa with the eastern shore of North and South America was dismissed an illusion. But new evidence appeared and the old heresy became the new orthodoxy.
For generations millions of people suffered from gastric ulcers that were supposed by physicians to be caused by stress. The few doctors and scientists who thought the malady looked like a pathogen-caused disease were treated as fools. But the fools never quite went away and in time their interpretation proved to be the correct one.
Governments long looked on their budgets as bigger versions of family household budgets. When times turned hard, governments cut back spending just as households must. A handful of dissidents said this was precisely the wrong approach, that governments were not like households. The right thing to do in a depression was for governments to spend more, not less. The world endured several depressions under the old regime; indeed, not until the covid pandemic did the idea of countries spending their way out of depression really catch on.
In each of these cases, the heterodox ideas were never completely suppressed, but remained in the intellectual gene pool to emerge and thrive when the old conditions had changed. Had they been wholly crushed, the needed changes would have come even more slowly than they did, if they came at all.
The usual argument for free speech is that ideas ought to be able to compete on a level field and the best ideas will come out on top. The banana analogy suggests taking this concept one step further. Let the best ideas come out on top, but make sure the worse ideas are not entirely suppressed. Suffer the cranks; their ideas don’t seem optimal at the moment, but a new moment will come when those ideas might be just what we need.
And may we have bananas forever.