Two friends are talking about crazy medical treatments. The first one, Freddy, is full of enthusiasm and energy, saying "I bet if you rub carrots on your eyeballs, it will fix your near-sightedness!" Seeing Freddy caught up in yet another flawed pharmaceutical fad, the second friend, Nelson, adjusts his glasses and responds disdainfully: "No way, idiot. Rubbing carrots on your eyes does literally nothing to fix myopia. It’s totally useless!" Who’s right, and which attitude is more scientific?
In modern pop-science culture, positive statements ("carrots help your eyes") receive scrutiny and criticism while negative statements ("carrots don’t help your eyes at all") are given a free pass. But negative statements of the form "X does literally nothing" are extremely difficult to prove. The problems is that modern industrialized science tend to be highly reductionist, taking complex problems with millions of dimensions and reducing them down to a mere handful for the sake of testability and convenience. However, whatever works for convenience in application isn’t sufficient to give us a true and final answer in theory. It just means that, according to the dimensions that we chose to investigate, at that particular time, with those particular instruments, and with these methods and caveats, we weren’t able to measure an effect. It isn’t a conclusion to our investigation at all.
Most reasonable pop-science fanboys will agree with the previous paragraph in theory, but in practice, we still see this attitude, which I will call the "zero effect fallacy," show up very often in contemporary conversations. Here are some examples of what I mean by the "zero effect fallacy":
"Showing scary movies in the classroom has no influence on kids’ behaviors."
"Eating animal testicles does literally nothing to improve your health."
"Repeatedly kicking trees with your shins doesn’t do anything to strengthen your bones."
The zero effect fallacy is the false idea that you have proven the null hypothesis to be true. But this is an irrational leap of faith. A failure to prove an alternative hypothesis doesn’t mean you’ve successfully proved the opposite. This false equivalency has led to a disaster of moderate severity for truth-lovers in our generation.
Why is the zero effect fallacy so common among middle-class, white collar, moderately-educated science fans? Part of it is due to specific metaphysical assumptions of the human self which have become popular in our modern age: primarily the idea of the human as a stony, machine-like, atomized, modular Cartesian soul that is hardly influenced by its external environment. In this view of the human self, the human is always an active agent, never a passive receiver, and hardly changes or is affected by anything other than what it rationally chooses for itself. Any influencing power requires strong forces that are always consciously recognized. Mental and bodily phenomena are reduced to a rational, mechanistic processes of cause and effect, and these causal chains are very short, easily detected, don’t influence each other, and terminate quickly.