“While still a kitten, all fluff and buzzes, Pete had worked out a simple philosophy. I was in charge of quarters, rations, and weather; he was in charge of everything else. But he held me especially responsible for weather. Connecticut winters are good only for Christmas cards; regularly that winter Pete would check his own door, refuse to go out it because of that unpleasant white stuff beyond it (he was no fool), then badger me to open a people door. He had a fixed conviction that at least one of them must lead into summer weather. Each time this meant that I had to go around with him to each of eleven doors, held it open while he satisfied himself that it was winter out that way, too, then go on to the next door, while his criticisms of my mismanagement grew more bitter with each disappointment. … he never gave up his search for the Door into Summer.” Robert Heinlein, Door into Summer (1956)

When my children were young, I read one of them Heinlein’s science fiction novel “Door into Summer.” It is about an inventor, Daniel Boone Davis, whose fiancée Belle and partner Miles deceive him into giving up control of his company. Unlike his cat Pete, who was forever looking for that door into Summer, Daniel found his own door into summer. This one was through time. In 1970, he went into suspended animation for thirty years, traveling to the future without aging. In 2000, he took a job as an inventor and became puzzled by the evolution of one of his previous inventions and by the marriage of Ricky, an eleven year old girl he once knew, apparently to a man with his name. In 2001, in an effort to change his destiny, he tracked down a mad scientist who had a time machine and used it to go back in time to the year 1970. Then, using suspended animation again he went to the year 2001 and married Ricky who had gone into suspended animation when she was 21.

This essay is about my own doors into summer. Each one is like a perspective lens helping me to open new vistas to navigate current worlds, and apply perspectives from one world to another: Reading books, meta-stating, and crossing fields are processes, each with their own door.

  • Reading a book opens a door between what I know and what I don’t know. It gives me access to other people’s knowledge and perspectives. This allows me to expand my own knowledge and perspectives.
  • Meta-stating opens a door between a reference mind-body state and a another state. This allows me to bring the reference state to bear on that second state, so I can experience a broader perspective and increase my behavioral flexibility.
  • Crossing fields opens a door between one field and another (e.g., applying psychology to economics)This allows me to bring the knowledge and techniques from one field to bear on another, and create better models and solutions to problems.

These doors, like portals from one world into another, help me bring resources to bear on my current experiences and modeling projects. Many of you use some of them already. And if you don’t, you might find some useful in enhancing your own knowledge and performance. Let’s explore each door in turn.

Reading Books

In my home, there are 360 feet of bookshelves, distributed among three floors, and containing about 4700 books. I also have about fifty books on my Kindle and over three hundred books in my Audible library. If you stopped to look at each one for ten seconds, it would take you fourteen hours to look at them all. I started acquiring books on science, mathematics, and science fiction novels when I was a teenager. Later, I branched out and started buying books in philosophy and the social sciences. I even started reading novels that had nothing to do with science!

When I was in high school in the 1960s, there were no personal computers, no Internet, and no Google search. There were just books. (There were also no electronic calculators, just slide rules). As a teenager, I immersed myself in the high adventure and romance of science fiction, and transferred those feelings into a worship of science. Being a shy teenager with negligible social skills, I fantasized about my relationship with girls.

I discovered a compelling essay “Stress Analysis of Strapless Evening Gown” by Charles Siem (1956). Siem shows force diagrams that illustrate how the gown manages not to fall off. He also points out some of the danger points for wardrobe failure that a designer must address. Near the end of the analysis, the author says “Many females have been asked to volunteer for experiments … in the interests of science, but unfortunately, no cooperation was encountered.” That essay was definitely on the same wavelength with me as a young teen, who was interested in both understanding science and girls.

When I became a little older, I remember doing my own experiments in an effort to understand girls, resulting in embarrassing near disasters. On a rare date in my late teens, I wondered if I should hold the girl’s hand. I kept moving from one side of her to the other, trying to decide if moving her purse to the side opposite me meant she wanted to hold my hand. My experiment ended when she said “my hand is cold” indicating she wanted me to hold her hand.

My understanding of relationships matured over the years, illustrated by my recent interest in the books: “The Mathematics of Love: Patterns, Proofs, and the Search for the Ultimate Equation” by Hannah Fry (2015) and “The Mathematics of Marriage” by John M. Gottman, James D. Murray, (2002). Fry’s topics include: “What are the chances of finding love?”, “How to optimize your wedding”, and “How to live happily ever after?” Her last topic summarizes some of the findings in Gottman and Murray’s book. Gottman observed married couples conversing, and from these observations could predict whether the couples would divorce with over 90% accuracy. Paradoxically, those couples who argue frequently about small things and repair their issues fare better that those who tend to bottle their emotions and argue only about really big issues.

Gottman’s experiments also indicated that respecting your partner, especially avoiding eye rolling, also helps. I wondered if “sticking out your tongue” at your partner was equivalent to an eye roll. Doing an informal survey, I asked three women I know about the differences. All said the two actions have different meanings. One said the difference was huge. An eye roll signifies superiority, possibly with the words “Oh my God, are you kidding me? Again?” Two said it is also disrespectful. Whereas, sticking out your tongue is a playful way of arguing, possibly with the words “so there, take that.” There is always new things to investigate, something to learn, and not all from books!

During my high school years I also discovered many “classics” of science, mathematics and philosophy. Even now, when I pick up some of these books and browse through them, I smile at some of the urgent notes I wrote to myself, like: “Reading Must!! Take notes and report [to myself] important ideas (July 1964).” Those notes were in the book “Philosophy of Mathematics and Natural Sciences (1963) by Hermann Weyl. The Dover Publishing company reprinted many of these books at an affordable price to a young teenager (e.g., $1.35). Three such books, all by Henri Poincare, remain my favorites: “Science and Hypothesis (1902)”, “The Value of Science (1905”), and “Science and Method (1908).”

In the book “Science and Method”, Poincare discusses how he gets insights and makes discoveries in mathematics. He uses both his conscious and unconscious mind, frequently thinking about problems as he falls asleep or wakes up. I have successfully done the same thing over the years, and without losing too much sleep. People still quote Poincare’s work. For example, Gary Klein, in his book “Seeing What Others Don’t: The Remarkable Ways We Gain Insights (2013) quotes Poincare: “Creation …does not consist in making new combinations…The combinations so made would be infinite in number and most of them without interest. To create consists in not making useless combinations.” Poincare suggests his unconscious mind plays a role in this selection process. This is in sync with Salvador Dali, who said “While we are asleep in this world, we are awake in another one.”

From a young age, books opened up new worlds for me, helping me move across the boundary from the known to the unknown. I approach each new book with the questions: What mysteries does it uncover? How can I apply it? Who can I share it with?


Suppose you see a potential danger and feel fear. We call this a primary state, since something outside of you triggers it. Being human,you will probably reflect on that fear. Many of us are ashamed of being afraid. This feeling is a meta-state, a state about another state, and is triggered from within yourself. It sets a new frame of meaning for the original state. Now, your relationship with the state of fear is shame, i.e., shameful fear. How would you experience fear differently if instead you were curious about your fear?

Sometimes self-reflection places us in a state of mind (e.g., self-loathing) that is not useful. At other times, it places us into highly desirable states, such as joyful learning or calm fear. Self-reflection can give us the ability to gain new perspectives, understandings, insights, and choices. I am frequently in a learning state when trying to understand some almost incomprehensible topic. Often my learning is driven by intense curiosity leading to “curious learning” states. My state of curiosity is probably more like “persistent curiosity” since I really want to satisfy my curiosity, and find it hard to give up when I hit what seems like a brick wall.

My current modeling project is to understand and model the Classical Maya Collapse. This is where Maya city-states collapsed over a period of 150 years (see my essay “How I was Drawn into Modeling the Classic Maya Collapse”). I first read about this in the 1985 book by John Lowe: “The Dynamics of Collapse: A Systems Simulation of the Classic Maya Collapse.” I wondered if I could reproduce Lowe’s results using a modern-day simulation application. Here is a partial list of the states I experienced during different phases of the project.

  • Curious Learning – when trying to understand Lowe’s model and the empirical data he used.
  • Frustrated Curious Learning – when trying to understand Lowe’s simulation software code. He used the old simulation language GASP IV to generate the results of his model. I purchased a used copy of a 1974 book on the Gasp IV language and tried to understand Lowe’s code. This textured my curious learning state with a bit of frustration since I did not completely understand the language or his code. However, I felt I understood it enough to get the gist of what he did. I minimized my frustration by thinking that GASP IV was probably on its last gasp.
  • Curious Playful Learning – when I recreated Lowe’s model in a modern-day software, and was exploring “what-if” scenarios to see how I could best match the model to the data.
  • Serious Curious Learning – when I started gathering and reading six other books on the Maya collapse. I thought that this work could lead to a published paper on the topic and needed to do more research.
  • Curious Excited Learning – when I realized that a new approach I heard at a conference might help me extend Lowe’s model. I wondered if I could create this new model and better match the empirical data. Six months later (remember “persistent”), I discovered that I could, and am now working on a paper to describe the new model and its results.

Another meta-state, nicknamed “the genius state” is a highly focused state of commitment. This is a good state for writing. When in this state you can lose all sense of time and focus completely on your writing. You can easily go into and out of the state. So if something interrupts you and you leave the state, you can easily get back into it. I can sit at my desk and write for an hour, deeply absorbed in the activity, hardly noticing the time go by. On May 10, 2004 Diane Rehm (a former local talk show host) interviewed Jim Lehrer (author of Flying Crows) and his wife Kate Lehrer (author of Confessions of a Bigamist). Kate said that Jim, unlike her, could easily go into and out of a writing state. In fact, he could write a few paragraphs during a break in the interview and go back to the exact point he had left earlier. Jim said that he could be writing an article on Iraq, come to a dead stop, and then begin writing material for his new novel. He said he could do this because of his training as a journalist. It would be interesting to explore how training in journalism would support access to a genius state. I suspect a journalist has mastered the ability of getting to the point in a short time to meet urgent deadlines. (See my Meta-states and Frames resource map for more details about meta-states.)

Crossing Fields

As we grow up and seek to find our way in the world, our culture tells us we must specialize to succeed. I probably never grew up since specializing in just one field was not my career path. A possible path for me might have been to learn solid state physics, get a PhD in the field, and get a post-doc position to help another researcher work on a more specialized problem. Then, perhaps I would find a faculty position somewhere, and work with graduate students on even more specialized problems. That was a path not taken. Rather than become a specialist within physics, my inclination was to be a generalist. My thesis adviser, Max Dresden (also a generalist), thought he would have trouble finding a post-doc position for me since I did not specialize. It turned out that was not a problem since I did not want one. Except for a stint in the Army, which provided a dose of reality, I had been in the academic world for too many years

I began my career as a generalist, by bringing one field to bear on another. In this case, I brought mathematics to bear on physics. When asked about my PhD, I usually say it is in Mathematical Physics. Isn’t the use of the word “mathematical” being redundant? After all, ask anyone who has ever taken a physics course, or opened any physics book. All you see is mathematics! The simple answer is that in mathematical physics you apply more advanced mathematics than you would find in typical physics courses. In graduate school, I worked on three separate topics. All of these topics brought mathematics to bear to solve complicated physics problems, resulting in four published papers before I graduated. I included two of these topics in my PhD thesis; one topic used the mathematics of symmetry (Group Theory) to solve a complicated equation in quantum mechanics, and the other used an exotic mathematics (Non-Standard Analysis), which included infinite and infinitesimal numbers, to create a bridge between the micro world (statistical mechanics) and macro world (thermodynamics).

I looked at my actual diploma recently and was surprised that it only mentioned I had received a Doctor of Philosophy. It did not mention physics at all, nor even the Physics department where I spent about seven years of my life. (I even looked at the back.) I never actually attended my graduation. They mailed me my diploma, and I guess I did not pay much attention to it at the time. I asked someone about his PhD diploma, and he said that his did not include his field of study either. Perhaps universities expected us to cross fields after getting an advanced degree.

A central theme in my style of modeling (and my life) is to be on the boundary of one field (e.g., System Dynamics) and another (e.g., coaching), and bring the first to bear on the second (e.g., coaching ) when modeling within the second field. A physicist naturally brings mathematics to bear on physics when creating models of the physical world. That is not out of the ordinary. What about bringing mathematical physics to bear on the financial markets (econophysics) or psychology to bear on economics (behavioral economics)? Richard Thaler recently won an Nobel Prize in Economics for his work in behavioral economics. In New York Times article (October 9, 2017) Binyamin Appelbaum said “The Nobel committee, announcing the award in Stockholm, said that it was honoring Professor Thaler for his pioneering work in establishing that people are predictably irrational — that they consistently behave in ways that defy economic theory.”

Max Dresden was great at applying physics to other fields. One reference he mentioned in a class was a book “Introduction to Quantitative Aspects of Social Phenomena (1974)” by the physicists Elliot Montroll and Wade Badger. It was the first place I saw mathematics applied to this subject. Among the topics they discussed were the growth of cities, competition between species, and the arms race. In 2000 (unlike Daniel Boone Davis), I discovered the field of System Dynamics. It is capable of addressing problems in the same areas Montroll and Wade covered in their book, and allows me to easily run “what if” scenarios to test different solutions or organizational policies. No matter what you do, there is power in bringing one field to bear on another. On the other hand, you may need to contend with a “not invented here” mentality because of resistance from the status quo when crossing fields. In my experience, the results are worth it.

Being a generalist and knowing the value of bringing one field to bear on another, I looked for fields that have application in many other domains. So far, three have drawn my attention: Mathematics, Neuro-Linguistic Programming (NLP)/Neuro-Semantics, and System Dynamics. These days much of my modeling work includes combining techniques from one or more of these fields. In “Systemic Coaching (2012)”, a book I co-authored with Michael Hall, we applied techniques and perspectives from System Dynamics (system thinking) bringing these to bear on Neuro-Semantics (coaching). My work with Michael Coopersmith on “Interest Rates and Inflation (2016) ” brought advanced mathematics (time-delayed differential equations) and System Dynamics tools to bear on economics. My work on the Classic Maya Collapse combines material from the fields of History, Mathematics, System Dynamics, Infectious Diseases, and Network Science.

In the late 1960s, I heard the famous astronomer Harlow Shapely speak about our expanding universe, which you can think of as a balloon expanding from an initial explosion (affectionately called “the big bang”). He mentioned a question he got from an elderly woman: “What if I went to the very end of the universe and poked my finger through it?” What doors can you poke through, perhaps with more success? What are your doors into Summer? If you don’t have them, “what if” you did? What would they be?


I want to thank Claire Kurs and Daniel Gambardella for editorial suggestions, and three women who participated in my survey. The photo that forms the basis of the graphic in the introduction was taken by Claire or me during our vacation in Varenna, Italy. I created all the graphics.

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