In ancient Greece, worshippers approaching the Temple of Apollo at Delphi passed by a column at the entrance. It bore two carved inscriptions: “gnothi seauton” (know thyself) and “medan agan” (nothing in excess). Think of these inscriptions not as laws or decrees, but as heuristics. A heuristic is a mental shortcut or rule of thumb that simplifies decision-making or problem-solving, supporting the user in making up his or her mind without paralysing delay, despite not having all the relevant information on any given occasion. For most humans this is 99.9% of the time.

Because of their character as economical shortcuts to intelligent thought and action, heuristics are excellent and highly valuable technologies for people who aspire to pursue a good or, at least, decent  life - provided, that is, they select the right heuristics to guide their thinking in the first place. Tracking down and choosing the right heuristics is potentially life-changing. 

In Human Technologies, students are introduced to a series of heuristics throughout the course. For example, they are encouraged to conceive of themselves as somewhat alike to a Matryoshka or Russian doll, with ‘layers of being’ nested within them that have a profound and ongoing effect on their experience of life. Of course, we’re not “really” Russian dolls, but adopting the image as a heuristic can help remind us both of our complex personal histories and the influence that the past can exercise on current preferences and behaviour. 

Similarly, students are introduced to the notion of the ‘triune brain’, which suggests that we can usefully think of the human brain as being composed of three parts: the lizard, the mammalian, and the primate; not because this is literally ‘true’ (it isn’t), but because appreciating that your brain has functions that operate automatically (or autonomically) and below consciousness helps you make sense of the ways in which you conduct yourself, including on those mysterious occasions when you are unable properly to account for your actions. Again, for most humans this is probably about 90% of the time.

Back, then, to the Temple of Apollo at Delphi. My contention is that the two heuristics inscribed there (Know thyself; Nothing in excess), are two of a trio of heuristics it is vital to know and to navigate by, so as to lead a decent life. There are more besides, naturally, but, taken together, these three provide a good start. 

The absent third is a heuristic best expressed in its iconic form - and is found in the teachings of another equally venerable wisdom tradition, this time from the other side of the world: the yin and yang symbol. 

In Taoist metaphysics, the Tai Chi symbol (as it is also known) reminds us of the dualistic nature of the universe, in which opposite forces are interconnected and interdependent, creating a harmonious balance. The symbol of yin and yang, with its black and white swirling pattern in which a dot of each colour (or absence of colour) is embedded in the body of the other, illustrates the idea that each force contains the seed of its opposite and that they are in a constant state of dynamic equilibrium. In fact, we’re instructed, these apparent ‘opposites’ are merely emanations of the endless interplay of the true concinnity of reality, and appear as distinct only due to the peculiarities of our limited human perception. 

Know thyself - warts and all; lizard brain and all; urgings of the unconscious and all; and face up to it. Facing up to it, conceive of your so-called strengths and your so-called weaknesses as emanations of a dynamic, evolving, interpenetrating swirl of being, in which the good and bad, the true and false, the admirable and detestable, are expressions of the full complexity of your ‘self’ (your Self1). Remember that you can take responsibility in guiding this evolution (towards your always receding, never-to-be-fully-accomplished Self2): knowing and embracing yourself and your propensity for both the good and bad, the true and false, the admirable and detestable, adopt as the leitmotif of your passage through life the principle of “nothing in excess”: beware certainty, beware dogmatism, beware tyranny of thought, beware hubris. 

In a phrase: the middle way. In a word: balance.