Monday, July 13, 2009

Before and After

Two photos of my garden, one taken in April (top) the other today (July).

Wednesday, July 8, 2009

Monday, July 6, 2009

How is Finance like a Sand Pile?


Why is it that nobody in the mainstream media seems to know anything about economic theory or the dynamics of financial markets? This morning's Washington Post contained yet another column asking why it is that economists failed to predict last fall's financial crash. The title lays the blame squarely at economist's feet: "Economists out to Lunch."

As if these economists were sitting at the controls of a machine they fully and completely understand. As if something like the crash we experienced could be predicted. As if the financial system had levers to pull or buttons to push that would yield predictable outcomes.

This all seems quite ludicrous to me. Even though I am not an economist, it seems clear that our economic and financial system is a complex system, with all the ramifications that has for predictability--or lack of predictability. It is a system comprised of multiple, nested feedback loops. These types of systems self-organize and display dynamic behavior that is well-understood from complex systems theory.

Not that you would ever know that from reading the newspapers.

One type of self-organized behavior that has been considered by those seeking to describe the dynamics of financial markets is exemplified by a sand pile fed from the top by a stream of sand grains. The dynamics of this sand pile exhibit what is known as self-organized criticality, or SOC.

The grains tumble slowly down the sides of the sand pile, coming to rest at various points along the slope. The pile slowly grows as sand is dribbled onto the top until, suddenly, the system becomes unstable and a small avalanche occurs. A rush of sand tumbles to the bottom, returning the remaining pile to a situation where additional sand can be added--but only for awhile. Small avalanches occur at random intervals and it is never entirely predictable when they will happen.

The sand pile's SOC dynamics exist because this system has an attractor that is simultaneously stable and unstable. This type of attractor is known as a critical point. It is essentially a mountain pass in the hilly terrain that characterizes the dynamic landscape for the system.

This mountain pass is a saddle point: if we stand at the point and look in one direction, the mountain slopes upward. Turn ninety degrees, though, and the mountain slopes down. Another ninety and it slopes up again. Completing the circular spin as we stand at our saddle point, we see the mountain sloping downward again. Sand grains roll down the mountain slopes toward this saddle point but when the resulting sand pile becomes too big, it collapses and rushes away into the surrounding valleys.

SOC has been suggested as the explanation for a variety of phenomena: forest fires, earthquakes, and, yes, financial markets. The common feature in systems that are governed by SOC is that they are driven by a persistent external force. In the case of the sand pile, it is the stream of sand. In the forest fire example, it is thought to be the slow accumulation of dry fuel. In the earthquake example, it is the constant pressure from colliding tectonic plates pushing on a fault line that will, at a random and unpredictable time, slip, causing a quake.

I would love to see a thoughtful discussion of the possible role of SOC in economics and financial systems. Nobelist Paul Krugman's ideas come close, but he seems to shy away from precise scientific language that would make it clear to me that he agrees with the idea that economic systems are complex, self-organizing and, thus, subject to the natural laws for these fascinating types of systems. I will keep looking, but please post links if you know of any relevant work.

Friday, July 3, 2009

Fingerprints of God: A Review


Barbara Bradley Hagerty's recent book, "Fingerprints of God: the Search for the Science of Spirituality" is great and I thoroughly enjoyed reading it. Hagerty, a religion correspondent for National Public Radio, is a superb journalist who has brought her superior reporting skills to bear on the question, "Is there more than this?"

In this book, she presents evidence gleaned from countless journal articles, interviews and even experiments she participated in herself that address the question of whether there is a God and, if so, does that God leave any measurable traces, or fingerprints, on us when we have a spiritual experience that brings us into contact with that God.


The topics in this book cover a wide range, from neurochemistry to mystical experience, quantum physics to psychedelic drug use, epilepsy to scientific studies of meditation, and all are explored thoroughly and explained well. I especially liked her accounts of mystical experience and its effects on the lives of individuals who had this especially profound type of spiritual experience. Her explanation helped me understand my own life better and I experienced more than a few "Aha!" moments when reading through this section.


One of the more appealing parts of this well-researched survey of scientific studies of spiritual experience, is Hagerty's personal story which she weaves through the book, giving it a narrative thread that personalizes what could have been a dry presentation of facts. She seems to have been wary about doing this and writes, in an early chapter,

"Transforming insights usually come in small moments and pedestrian crises. So it was for me...I needed to cross the river and immerse myself in the unnerving questions about God, and reality, and whether what I instinctively believed was true--or rubbish.

"I was, to be honest, skittish. Skittish about ruining my reputation in a career where few people believe in God and fewer still bother to distinguish spirituality from religious politics. More than that, I was skittish about submitting my faith to scientific tests, exposing it to the possibility that the most profound moments of my life were nothing more than, say, electrical activity in my brain."


Hagerty's main focus in the book is the intersection of the spiritual with the brain as a material object comprised of cells and molecules. She leads us, using an engaging narrative technique, on her search for physical evidence that spiritual experience changes the brain. I found the emphasis on the need to find physical markers of spiritual experience a little excessive, but understandable in light of Hagerty's religious background in Christian Science.


I found it puzzling, at times, though, that she wanted to draw a sharp line between our bodies and our spiritual selves. At one point she even asks, "Can one's thoughts affect one's brain states? Can thoughts affect matter?" without addressing the everyday example of just this: learning. Every time we learn something new, our thoughts affect our brain states. When we study, synapses are formed or strengthened and a real, physical effect is the result of all that studying. Her insistence that only a spiritual explanation would suffice for the influence of the mind on the physical brain was not consistent with the rest of the book.


Nevertheless, this is a minor quibble and I highly recommend this book. Hagerty is a great reporter, an excellent science writer and an intrepid explorer of some of the most intriguing aspects of the universe we find ourselves in.