We humans have a problem: our brains are fairly small and we’re hardwired to do as little thinking as possible.

For most of our evolutionary history we lived on the margin. Calories were scarce and uncertain so it made sense to conserve energy as much as possible. That’s why even today people who live in more “natural” conditions spend much of their time sitting around in the shade staring off into the distance. It’s been estimated that a typical hunter-gatherer spends not more than four hours per day being active. Now the human brain can burn up to 30% of the body’s blood glucose when it’s being used, so it’s pretty obvious that we evolved to use it as little as possible. That was just fine back when our environment was the African savannah or the primordial forests of Eurasia. Today, however, it’s a whole different ballgame.

People often think about evolutionary selection pressures as being all about predators and prey, but this isn’t in fact the case, especially for group animals. What matters isn’t being faster than the lioness, it’s about being faster than your peers so the lioness will take one of them for dinner instead. And it’s even more complicated than that, because group animals are primarily in a never-ending contest for personal gain. Every male wants somehow to get access to the best females, all the females want access to the best males, everyone wants to get a bit more than their share of the available food, and many animals (us included) use trickery to gain advantage.

What this means is that we’re in perpetual danger of being taken for a ride. As the saying goes, “if you can’t spot the patsy, then you’re the patsy.”

The problem for us is that we have inordinate difficult telling when we’re being fooled. Back on the savannah it was bad enough but in today’s complex technological fast-moving world it’s a whole different problem entirely. With all the information we’re perpetually bombarded with, how can we tell what’s real and what’s fake? Especially as 90% of what we encounter will be unreliable at best.

The good news is, there are some techniques you can use to be less easily tricked.

Let’s take some examples of arrant nonsense that have been floating around for a while and making fools of a huge number of people and then examine how we can see through the fog of absurdity to reach clarity.

To begin with, let’s take “cleansing.” A great many people have spent considerable sums on “treatments” involving putting “special” powder into a container of warm water (or using an expensive “ionizer”) and then putting their feet in it for a while. In the magical thinking of this hilarious con, the footbath “pulls the toxins from your body.”

How could we know this is a con of zero merit? Easy: we think it through from first principles.

Here’s how to do it: we know we are mammals, we know mammals are pretty self-regulating animals. When we’re thirsty we drink, when we’re hungry we eat, when we overheat we sweat to cool down, and so forth. Could we as a species have survived for hundreds of thousands of years without being able to clear out toxins, waiting desperately for some con-artist to invent this magic footbath powder? Or would evolution have resulted in our bodies having some way to clear out toxins on a regular basis? Hmmm…. Oh yes! We do! They are called kidneys. They are so important we have two of them. Furthermore how plausible is it to imagine there’s a secondary, and until now entirely unused, mechanism involving the soles of our feet — soles that for nearly all of our evolutionary history had to be the barrier between us and whatever muck we were walking over. How on earth would such a mechanism have evolved and then been retained for hundreds of thousands of years during which we couldn’t use it because the “special” treatments hadn’t been invented. Not really plausible at all, is it?

Now that wasn’t too difficult. Just some basic reasoning.

Let’s look at another con that seems to have enduring appeal. It’s called “the power of attraction” among other terms. Basically it means that if you concentrate on something you want hard enough, the universe will ensure you get it.

This is tremendously appealing to our tiny brains and it’s why people pray. Surely I deserve the bicycle, the promotion, the remission of my cancer? And if I deserve it then surely the universe, god, goblin, whatever, has to give it to me? Because the universe is all about me, right?

Skipping over the obvious fact that the universe is not in fact all about anyone, we can wonder how this miraculous mechanism would operate. By what invisible magical means would Event A be caused by merely wishing for it? Do we lose weight merely because we wish for it? Do we grow taller or more attractive or younger merely by wishing for it? Does the car start merely because we want it to? Does the money in our bank account increase merely because we really, really would like it to? Is there in fact any event at all in our daily lives that reliably occurs merely because we want it to, without any concrete action taken by us or by someone else on our behalf to make it happen?

Hmmm….. nope.

So either the laws of physics have been re-written and the entire universe came into existence 13.8 billion years ago merely in order to ensure that I get to have sex with my attractive young next-door neighbor or… I’ve been conned.

Which is the more likely scenario?

We can take one final example, this time of an urban myth which like most simple-but-wildly-wrong myths spread with great ease because few bothered to stop to think about the implications: the idea that we only use about 10% of our brains and hence there’s this mystical “untapped potential” just waiting for us to use it.

How credible is this idea? Let’s see…

We know all creatures are perpetually engaged in a struggle for survival. Every creature has to find food, avoid being eaten, and attempt to mate. Meanwhile its immune system is fighting off would-be parasites, bacteria, and viruses. All of this takes energy and energy is generally scarce (remember, we’re the only animal that’s developed the supermarket, and that only happened a fraction of an eye-blink ago in evolutionary terms, so it doesn’t count).

Evolution therefore permits creatures to develop only those attributes that contribute to its ability to survive and mate and thereby pass on the DNA that encodes for such attributes. There’s nothing left for frivolity. So we don’t see that elephants have twelve legs but only use four; we don’t see that birds have six wings but only use two. In fact nowhere in the vast panoply of life do we see any significant feature that is redundant and that’s because nature isn’t frivolous. Forget “what about the human appendix?” as an argument, because that demonstrates the point rather than defeats it: the human appendix is a vestigial remainder of something that was important a long time ago and now is gradually being lost because we don’t need it any more. We’re not keeping it as a frivolous unused extra.

All we need is the most basic understanding of evolution and a pretty basic knowledge of the life around us to see immediately that the “10% brain use” idea is not only implausible but silly. We use all of our brains. That’s what they are there for. Sure, we aren’t actually very smart and we make a lot of obvious blunders and most of human history is a tale of one stupid decision after another. But that’s not because we’re not using all of our brains; it’s because we’re doing the best we can with what we’ve got and the human brain isn’t actually adapted for doing much thinking. It’s adapted for a life on the African savannah and the primordial forests of Eurasia where not a lot of thinking was required. But even so, our brains are capable of a bit of reason here and there provided we get into the habit.

Once we get into the habit of stopping for a moment to think things through, we can spot all manner of con tricks and nonsense. Which means we can make better decisions in our lives and be in a much better place to work towards outcomes we want and that are achievable.

Isn’t that better than being the patsy all the time?

Anyone who enjoys my articles here on Medium may be interested in my books Why Democracy Failed and The Praying Ape, both available from Amazon.