Monday, June 18, 2012

Working on evidenced based reasoning

Evidence-based reasoning has been on my mind lately. This past week I participated in a meeting of state teams from across the nation about the Next Generation Science Standards, particularly focused on what high school graduates should know and be able to do in order to go to college or enter the workforce. It really struck me how evidence based reasoning is involved at many different levels.

During the some of the preliminary sessions presenters addressed the question, "why new standards?" One point they emphasized that these (the NGSS as well as the Common Core Math and Literacy standards) are based on evidenced of what students need to know and not just a bunch of people in a room deciding among themselves. Evidence discussed included research on student learning, correlation of entrance exams with success in college, surveys of high school and college professors, and curricula from countries like Singapore that have shown to be doing a particularly good job educating their citizens. Another point of difference is the explicit intertwining of science and engineering practices with content, things like planning and carrying out investigations, collecting and analyzing data, and constructing arguments. Although these skills that support evidence based reasoning have been recognized in the past, they have been too easy to ignore in teaching and assessment, as it is much easier to teach and test understanding of specific chemical reactions than the process of using evidence to support a point.

It is really important to do a better job developing evidence-based reasoning ability in our students and future citizens. Issues involving science and technology like energy scarcity, global warming and biomedical ethics are only going to become more common and good solutions will require the ability to critically evaluate the evidence for different positions. In fact, so many of our societal and political issues need us to do a better job with evidenced based reasoning to really resolve complex issues.

Unfortunately, our cultural institutions are not doing a great job helping us develop evidence based reasoning. Schooling often seems to emphasize right answers instead of thoughtful reasoning, and current assessment practices don't help a lot. Churches seem often to focus on defending a particular doctrine or meeting emotional and spiritual needs. Then there are three fingers pointing back when I consider how much reasoning from evidence students are asked to do in a typical college science classroom. Our texts and curricula spend so much time racing through information about different topics that there is little time time to help students learn how that knowledge was developed or why we believe it to be true. Even in courses like physics where we claim to be teaching critical thinking, and even I, who should know better, catch myself falling into that trap. If we don't teach evidence based reasoning in our college science classes, where we educate our future teachers and citizens, where are we going to?  And if we can't learn to use it for understanding motion and molecules, how are we ever going to learn to use it for the most important issues?

Sunday, February 5, 2012

Light in Conflict

Engraving of Newton using a prism
to split white light into different colors.
One of the topics in my Light, Color and Vision course is the historical development of our understanding of light, color and vision, from early Greek philosophers to Albert Einstein. A critical and somewhat tragic chapter is that of the Englishmen Robert Hooke and Isaac Newton, colleagues and rivals during the dawn of modern science.

Robert Hooke (1635 – 1703) was a highly skilled experimenter who contributed to the study of Mars and Jupiter, behavior of gasses, understanding of elastic media (e.g. mechanical springs), fossils, and early microbiology, having built the first compound microscope. He was a leading member of the Royal Society, the world’s first scientific organization, through which he had contacts—and sometimes disputes—with many of the leading Europeans in the field of natural philosophy. Isaac Newton (1642 – 1727) was a first-rate mathematician, who invented calculus and gave a rigorous mathematical foundation to the study of motion of objects. Among other things, he had discovered that white light could be split into a rainbow through a prism, and developed the corpuscle theory of light, in which light was pictured as carried by miniscule, massless particles, with different colors corresponding to corpuscles of different sizes. Their relationship got off to a rough start when Hooke strongly criticized the first paper Newton submitted to the Royal Society discussing his discoveries and thoughts about light. It deteriorated further over Newton’s theory of gravitation, for which Hooke tried to claim partial credit and Newton went out of his way to deny.Newton then withheld publication of his book on optical phenomena until after Hooke’s death to deny him the opportunity to criticize it, and while Newton served as president of the Royal Society, the only known portrait of Hooke and a collection of his writings disappeared.

The two men’s theories of light were incompatible with each other.  Hooke pictured light as disturbances that propagate through a medium, like ripples on the surface of a pond, while Newton saw it as tiny balls passing through space and bouncing off surfaces. Waves are collective motions while particles are discrete things.  Which theory provided the best description of reality was an important question, but their disagreement went far beyond that to one of self exaltation and discrediting of the other, even to the point (at least in the case of Newton) using power and personal reputation to repress views with which he disagreed.  It worked for a while—for the next century most scientists held to Newton’s corpuscle theory, but then work by scientists including Thomas Young, Augustine Fresnel and James Clerk Maxwell increasingly supported its rival, and by the nineteenth century wave theory emerged victorious.

The victory was so complete that when a young, then unknown Albert Einstein published a paper seeking to explain a perplexing phenomena know as the photoelectric effect, he felt obliged to insist that his radical solution was a mere heuristic and shouldn’t be understood as a physical reality.  His idea was that light energy comes in discrete packets and different colors corresponded to different amounts of energy, a very particle-like behavior. Despite his claims of it being mere heuristic, the scientific community initially reacted quite negatively, and some historians believe that this idea delayed his receiving the Noble Prize.   Yet discoveries over the next couple decades showed that not only light, but also electrons, protons, and other subatomic entities are strictly neither waves nor particles in the classical sense.  They possess both particle-like properties and wave-like properties.  They are strange entities that are so different from everyday experience that even the best minds have a hard time explaining them conceptually, despite having mathematical equations that describe their behavior well allow allow us to design semiconductors and lasers.  In the end, Hooke and Newton were both partially right, and reality is stranger and more subtle than either imagined.

I look at the battles between Hooke and Newton, and it reminds me of the so-called debates on origins.  There are plenty of people on both sides that are so convinced that they possess the truth that they will attack the integrity and intelligence of their opponents, repress dissent in the classroom or the pew, and even undermine the idea that objective truth exists.  But I wonder if anyone really has the complete truth.  After all, both sides have persisted now for several generations, and it is rare for ideas and positions that contain no truth whatsoever to last that long.  I believe there are good reasons to believe that both sides are correct in some aspects.  When I consider the work of an infinite creator and how our universe and life came to be, I suspect that reality is stranger and more subtle than any of us can imagine.

Saturday, January 21, 2012

Genesis in Context


It is easy to underestimate how much cultural context colors our understanding, particularly for those who have not had significant interactions with other cultures.  This can be seen in modern reactions to how Mark Twain’s Huckleberry Finn describes African Americans.  Although considered by many as a masterpiece of American literature, the book has from time to time been the target of efforts to remove it from libraries or school curriculum, in part for its use of the N word to describe African-Americans.  In twenty first century American society that word is widely understood to carry a lot of derogatory connotations and we rightly oppose its use in almost all circumstances.  But Huckleberry Finn is not a product of twenty first century American, but nineteenth century society, a time when the N word was widely used to describe African Americans, who were often viewed as inferior to whites, perhaps even sub-human.  The irony is that Huckleberry Finn takes a stand against that attitude.  Although a number of characters treat Jim, the runaway slave, as little more than an animal, an important theme of the book is Huckleberry’s growing realization that Jim is a person just like him and the growing bond between them.  The author portrays Jim having a more noble character than many of the white people who populate the story.  The book refutes the foundation on which were built the racist attitudes of his day.  To demand that Huckleberry Finn conform to modern ideas of politically correct language detracts from the more important message the author is making.

The importance of understanding the cultural context is even more important when it comes to Genesis.  Genesis is not a modern work.  It was written several millennia ago in a Middle Eastern society thoroughly surrounded by a pagan world view.  It shares a number of elements with the contemporary Egyptian, Sumerian and Chaldean creation myths.  These include the world starting in a dark, watery chaos, the sky is something like a dome (the “firmament”) placed above the earth, humans formed from mud/dust/clay, plants and animals created in current forms, and a time scale far shorter and more recent than modern understanding.  But there are also radical differences that would not have been missed by the original audience.  Rather than a pantheon of gods and goddesses, each with their own area of power, emerging from the primeval waters or (often incestuous) procreation, there is a single, all-powerful God who wills the world itself into being.  Creation of different parts of the world happens not through haphazard processes including rivalries, murder and sexual liaisons, but through an orderly, intentional, fundamentally good process.  Sun, moon, earth, sky and sea are portrayed as inanimate objects, not deities; the author of Genesis declines to even dignify the sun and moon with names.  Humans are not afterthoughts, a result of rivalry between different gods, or made to be slaves of the gods.  Rather they are created in God’s image as sub-rulers of the world in a special relationship with Him.  Genesis’s view of the natural world and humanity’s relationship with it—much closer to the modern understanding its contemporaries in many respects—is unprecedented in the ancient world.  In contrast to both contemporary and modern accounts of origins, Genesis offers very little information of the mechanisms through which things came to be; the description of God forming the man and breathing into his nostrils in Genesis 2:7 is about the most detail offered.  Compare that to pages after pages or even books of describing the activities of pagan gods or the formation of galaxies and geological formations.  This lack of detail about the mechanisms suggests to me shrewd planning by a divine author anticipating how understanding of the physical world would change with time; descriptions of the mechanisms by which we now believe the world came into being would have been incomprehensible to the original audience, and those which they would have found reasonable would be nonsense to the modern mind.  The way Genesis seems anticipate modern understanding of the inanimate, orderly nature of the physical world, workings of natural processes, and humanity’s power over the Earth, convinces me that Genesis is a result of divine revelation.  In its historical and literary context, Genesis serves as a powerful refutation of the pagan world view and a foundation for teaching God’s people how to live in covenant relationship with him and the world.  To demand that it serve as a scientific text teaching us how and when the world came into being detracts from the far more important message the author is making.