"Our history shows us, again and again, that the revolutionary advances of our field have been driven by the occasional Platonic inner eye; by the creative demon that we too often fear to engage. All our revolutionary ideas have come from people who dream beyond anything they see in an external world; by people who have sometimes made large errors, but who have nevertheless trusted their minds." -John H. Lienhard, "Snares of Pool Boiling Research"

John Lienhard Puts History to Use for Today's Questions

John H. Lienhard, Ph.D., ASME Honorary Member and Fellow, rarely if ever fails to entertain and enlighten audiences of engineers and the public. He combines the broad brushstrokes of history with his expertise in heat transfer, once again, in a paper "Snares of Pool Boiling Research: Putting Our History to Use" (Proceedings of the 10th International Heat Transfer Conference, Brighton, England, Vol. 1, London: Chameleon Press, 1994, GK-11, pp. 333-348). While surely it is one of his lesser-known works, it captures his clarity of expression, his ability to transform near-incomprehensible concepts for literate consumption, and his uncompromising standards of readability and meaning.

Nothing speaks for John Lienhard like his own work, because few can match his wit and wonder. Such a title as pool boiling may not resonate with the general public, but Lienhard is not one to disappoint even the non-engineer. In "Snares," for example, where Lienhard speaks directly to engineers, much of the analysis is about sorting out their belief systems to determine what to do next and how to go about doing it?applicable to many interests. He draws the reader through an understanding of Aristotelian vs. Platonic logic: "You and I struggle with the same dialectic tension. Which eye do we use to look upon boiling? Psychologists (e.g.: Kiersey, 1984) find that 75 percent of our population is more Aristotelian than Platonist. That's an important number. It means that most of us expect to learn about boiling by reading our meters, photographs, and computer outputs. Only 25 percent of us seek to calculate truth from within our own heads."

The ASME History and Heritage Committee awarded John Lienhard the Engineer-Historian Award in 1998 for "Snares," his many other papers dealing with the history of engineering, and his organization (with Edwin T. Layton, Jr.) of symposium proceedings at the 1988 AIChE-ASME National Heat Transfer Conference that celebrated the 50th anniversary of the ASME's Heat Transfer Division. The committee acknowledges that previously he has received recognition for such outstanding contributions as his radio program Engines of Our Ingenuity, which is broadcast on National Public Radio and draws frequently from history of engineering topics, and his many lectures, which number some 70 a year for well over a decade. He received the ASME Ralph Coates Roe Medal in 1989 for his contributions to the public understanding of technology.

His nominator, former ASME History and Heritage chair Euan F. C. Somerscales, described "Snares" as "a most remarkable historical review of pool boiling heat transfer that uses the well-known analysis of scientific advances proposed by Thomas Kuhn in his book The Structure of Scientific Revolutions (University of Chicago Press, 1962). Kuhn's book was a landmark in the historiography of science and John Lienhard has shown, most convincingly, that it also applies to engineering research."

Lienhard asks, how do we gain new knowledge and how do we overcome our own resistance to revising old knowledge, i.e., change. He begins his example of pool boiling as "spit on a hot stove, the odd way that drops of water survive on a stove where it is red hot, but quickly evaporate away where the stove is cooler." He traces this history back to 13th century alchemy, the "knowledge of how we transmute matter by the action of heat and cold, or dampness and dryness." The lesson is simple: "The alchemists generally used Aristotle's science, but they ignored his scientific method of reaching truth by observing nature. Alchemy was, in fact, a very pure Platonic pursuit.

"Since heating and cooling, dampness and dryness, were fundamental alchemical processes, distillation and reflux condensation were primary tools of the alchemists. They were deeply involved with the processes we study.

"Why, then, is their work so invisible to us?"

Lienhard quickly traces the shifts in intellectual and scientific approaches, toward the use of external observation through an example of illustration, first in a symbolic and imaginative woodcut from 1845 versus a realistic woodcut some 46 years later, showing how the rules of perspective and geometry, combined with improved engraving, changed how scientists and engineers viewed observation and research. He notes: "Aristotelian botanists, anatomists, surgeons, miners, zoologists, and geographers all began walking around the Platonist academic establishment."

Early experiments with pool boiling proceeded from spit on the stove to experiments of water and wine drops on a hot iron (18th century): "As he reported his experiment [J.G.] Leidenfrost criticized [H.] Boerhaave for failing to separate himself enough from alchemical thinking. By now the new observational science was clearly in the driver's seat. Still, Leidenfrost uttered his criticism in the cautious language of an acolyte questioning God.

"Liedenfrost told us how long the droplet lingered on an iron spoon heated to different levels. Yet he added not a whit to our understanding of why the water survived longer at higher temperatures. Questions as to why things occurred drove the alchemists directly to the invention of hypotheses. Newton, by now the patron saint of the new rational science, had disposed of such questions summarily." Did Newton know when to quit, or have we merely stopped asking what the rational meaning of our experiments might be? History's lesson, according to Lienhard, is that any knowledge articulated in ways not currently acceptable or familiar becomes "invisible knowledge," and this is often determined by whether it is approached from a Aristotelian or Platonist perspective.

"Professor Lienhard's paper also shows that our modes of understanding natural phenomena, namely observation or deduction, played a significant role in shaping the history of our understanding of pool boiling heat transfer," continued Somerscales. "The author then uses his recognition of these two approaches to understanding the natural world, together with Kuhn's model, to suggest how those involved in pool boiling research can resolve the problems that still prevent our complete understanding of this area of engineering research."

Lienhard, who currently is the M.D. Anderson Professor of Technology and culture (which is a joint appointment between mechanical engineering and history) at the University of Houston, began his research into boiling in the mid-1970s. He had received his BS in mechanical engineering from Oregon State College in Corvallis, his MS in mechanical engineering from the University of Washington in Seattle (thermodynamics and applied statistics), and his Ph.D. in mechanical engineering from the University of California at Berkeley (fluid dynamics, thermodynamics, and heat transfer). His many grants over the years include studies of thermal convection and flow boiling, flow boiling burnout, prediction of thermal properties, etc., from NSF, NASA, DOE, EPRI, etc.

"Professor Lienhard's paper," noted Somerscales, "is strikingly different from most other review papers in that the author does not hesitate to introduce his own analysis of the situation under discussion, or point out conflicting claims and evidence." Lienhard's first-person style reflects an approach used throughout his work. He explained this in one of his radio programs: "In the end, every writer worth reading writes in the first person-maybe not in the matter of pronouns, but certainly in the matter of presence" (Engines of Our Ingenuity, No. 1047: "Who Writes Our Story?").

Throughout his lectures and radio programs, Lienhard praises the value of failures and human factors in their roles in eventual success. His look at hydrodynamic theory of boiling transitions also reviews failures as it ran "its course from its rocky beginnings in the 1940s, '50s, and '60s, through widespread acceptance in the 1970s, to what we can probably characterize as a mature skepticism in the 1980s." Lienhard sorts out what seems factual and what seems problematic today, with reminders for the traps that history has taught: (1) "Change comes from the outside and it is invisible to the existing community." (2) "We see what we expect to see." When we tune out history, when we tune out our inner eye, he seems to say, we passively await the world to provide the answers we refuse to see. Addressing engineers, Lienhard concludes:

"Our one-sided Aristotelianism takes another form which, I believe, is very damaging. Our review papers are remarkable in their failure to superpose our own thoughts on other people's work. Our review papers often report contradictory claims without noting the conflicts. It is as though observing is sufficient, and subjective reprocessing will soil us.

"Our history shows us, again and again, that the revolutionary advances of our field have been driven by the occasional Platonic inner eye?by the creative demon that we too often fear to engage. All our revolutionary ideas have come from people who dream beyond anything they see in an external world-by people who have sometimes made large errors, but who have nevertheless trusted their minds."