Using Perturbation Theory to Build Trading Models and Systems

I have recently finished reading Mr. Brian Greene’s book, The Elegant Universe. It is a fascinating book about string theory. One of the concepts Mr. Greene discusses is how physicists use perturbation theory to advance their knowledge and theoretical ideas.

Mr. Greene says that the mathematical framework of string theory is so complicated that physicists have to use approximate solutions and calculations, while initially ignoring some details. Later, these solutions and calculations are further refined as more details and knowledge are systematically included. The perturbative process can also be used to build trading models.

I had no idea of perturbation theory before reading this book, but I now feel it describes the process of how I created trading models. The stock market is also complicated and difficult to understand (probably more so then string theory). Initially, I began to systematically organize some variables, ideas, and concepts, while leaving others out. I began to create some general ideas, theories, and approximate solutions to trading. Later, with further testing, experimentation, and pain (the great teacher), I was able to increase my knowledge of how the market works, and I began to systematically include more details and concepts. This led to further refined ideas and theories which eventually became my trading models.

But here is some advice and a word of warning to traders out there—the key is to use a perturbative approach up to a point. The irony is that the more variables added to “refine” and “improve” a model, the more likely it is that the model will breakdown.

PLOTINUS AND BUILDING TRADING MODELS

Plotinus, the ancient Greek philosopher, did not have the creation of trading models in mind when he wrote this. Nonetheless, I think there are similarities between the creation of our trading models (our “statues”) and creating ourselves…

Withdraw into yourself and look. And if you do not find yourself beautiful yet, act as does the creator of a statue that is to be made beautiful: he cuts away here, he smoothes there, he makes this line lighter, this other purer, until a lovely face has grown upon his work. So do you also: cut away all that is excessive, straighten all that is crooked, bring light to all that is overcast, labour to make all one glow of beauty and never cease chiseling your statue, until there shine out on you from it the godlike splendour of virtue, until you shall see the perfect goodness surely established in the stainless shrine.

When you know that that you have become this perfect work, when you are self-gathered in the purity of your being, nothing now remaining that can shatter that inner unity, nothing from without clinging to the authentic man, when you find yourself wholly true to your essential nature, wholly that only veritable Light which is not measured by space, not narrowed to any circumscribed form nor again diffused as a thing void of term, but ever unmeasurable as something greater than all measure and more than all quantity—when you perceive that you have grown to this, you are now become very vision: now call up all your confidence, strike forward yet a step—you need a guide no longer—strain, and see. This is the only eye that sees the mighty beauty…