Conjuring up a well of limitless human potential, an old platitude – “you never know, unless you try” – is coming to now take on a slightly different inflection. In the process, the accuracy of the claim is likewise sliding slowly toward obsolescence. The original meaning of the phrase suggested that anything might be possible and only by trying any one thing would one know if he was capable of it. Though, I suspect, this phrase is quite a bit older than the flourishing of genetic approaches to evolutionary biology and psychology in recent decades, that flourishing maybe gives the phrase a richer significance.

The evolutionary approach to psychology has resulted in an understanding of the human mind as composed of a set of fitness benefiting mental modules, or mechanisms, or computational algorithms. Different scholars and schools prefer certain nomenclature. The basic idea though is largely the same. Sometimes compared to a Swiss army knife, the human mind has the emotional and cognitive traits that it has because the dispositions resulting from those traits provided fitness advantages for the organisms that possessed (or, more accurately, the genes that gave rise to) those traits. From the capacity to learn language and recognize predators to the preference for sweet foods and symmetrical faces, all these traits, modules, mechanisms, whatever you want to call them, offered fitness benefits in the environment in which they evolved. That’s why they were selected to be retained as part of the ongoing architecture of the human mind.

In some circles, these developments gave rise to ideas of what is sometimes called genetic determinism. At its most basic, this is the idea that the genes which we do, or do not, have determine the limits of our human capacity. And, in a certain sense, this is true. But it is not true in the popular sense that specific genes dictate a predetermined set of traits or characteristics that slavishly model a human person around some “blue print” in our DNA. First of all, the popular metaphor of DNA as a blue print simply isn’t accurate. There’s no little draftsman drawing of you in your nucleotides. The better metaphor for our DNA is a recipe. And the exact same recipe, if prepared by differ cooks, can come out a little bit different. Or, even a lot different, for that matter. This is why identical twins, with exactly the same DNA, are not in fact identical human beings – as illustrated by the fact that their parents usually have little trouble telling them apart. The term that identifies these variations is the phenotype. The exact same genotype can give rise to many different phenotypes.

Our genes interact with our environment and give rise to our own unique phenotype. So, our genes do set limits for what we can become; there don’t yet appear to be any genes for invisibility or time travel. Neither do they allow us to see ultraviolet or infrared light, as many birds and snakes do, respectively. But something in our distinctly human genome does give us some remarkable, yet highly flexible abilities: learning, language acquisition and what psychologists call theory of mind – the ability to intuit the desires and intentions of others from their behavior. The upshot of this is that there clearly is not some genetic determinism that slavishly builds us, item by item, from a blue print in our DNA.

Having said that, though, it turns out that there are some genes that do operate that way. Evolutionary biologists call them canalized genes. This is what is sometimes called hardwiring. If you’ve got the genes you get the trait. The bleak side of this story is the large number of diseases that result from specific, identifiable genetic facts. Downs syndrome, Huntington’s and Sickle Cell Anemia are examples. However, there are also extremely beneficial parts of our evolved psychology that appear to be genetically canalized – unless someone is missing some genetic ingredient of the recipe: early age facial recognition, a high frequency ability to recognize cheaters and a tendency to be attracted to those who have the best, least parasite infected, genes for mating purposes. Indeed, all three of the flexible capacities mentioned above – learning, language acquisition and theory of mind – arise in all clinically normal human phenotypes. And, indeed, even in contexts where the evolved traits no longer are of great benefit the canalized effects can be noted. For instance, though they no longer present nearly the danger they did in the ancient evolutionary environment, even in modern, urban, industrial societies, children continue almost universally to have anciently fitness enhancing fear of snakes, skeletons and darkness.

So, in fact, we are a bit of a mix. Part of what is remarkably human about us seems to be capacities to differentially develop in relation to inputted information. Yet, clearly, there are also these hardwired traits. This makes for an interesting challenge for those who’d make claims about our ability to reprogram or otherwise change who we are mentally. Much therapeutic and spiritual practice is premised upon a willed capacity for self-change: a kind of self-editing of our minds. But just what can we change? As should be clear from the above, anyone who’d claim we can change anything is as obviously wrong as would be someone who’d claim we couldn’t change anything. But where are the limits and what are the contours of possibility? This would seem valuable to know for those who didn’t want to waste much time and maybe money in practices claiming to achieve the impossible. But the allure of change, especially for someone suffering in their current psychological condition, can be great: mustn’t one try?

I suppose it’s in this way that that old platitude still has some legs to it. Maybe, for now, the only way you can know if you can change something about your mind – so as to behave in a way different from and preferable to past behavior – is to try. Being informed about the research on our evolved mind might be helpful, but if someone is determined to try to change something about themselves, I suppose we should be appreciative of their willingness to be a self-directed guinea pig. If they succeed, that’s great for everyone. And if they fail, well, you never know unless you try, right? (Though, obviously, claims of success are scientifically irrelevant unless assessed through a rigorously designed methodology.)

In the meantime, the evolutionary fields of biology, genetics, psychology, behavioral ecology and more continue in their interdisciplinary exploration of the contours of the evolved human mind. As time moves forward, more and more we will understand what is canalized and variable in human phenotypes. And, who knows, maybe one day you will know, without needing to try, or waste time and money trying to do the impossible. After all, not knowing may be full of hope, but knowing is full of truth.