[2005/01/29] Teach Scientific Controversy About Origins of Life
Teach Scientific Controversy About Origins of Life 01/29/2005
What
should public schools teach about life's origins?
Should
science educators teach only contemporary Darwinian theory, or not
even mention it? Should school boards mandate that students learn
about alternative theories? If so, which ones? Or should schools
forbid discussion of all theories except neo-Darwinism
?
These questions are arising frequently as school districts
around the country consider how to respond to the growing
controversy over biological origins. Dover, Pa., for example, has
attracted national media attention by mandating that students learn
about the controversial new theory of intelligent design. Of course,
many educators wish such controversies would simply go away. On the
one hand, if science teachers teach only Darwinian evolution, many
parents and religious activists will protest. On the other, if
teachers present religiously based creationism, they run afoul of
Supreme Court rulings. Either way, it seems educators face a no-win
situation.
So what should they do?
Surprisingly, there
is a way to teach evolution that will benefit students and satisfy
all but the most extreme ideologues.
Rather than ignore the
controversy or teach religiously based ideas, teachers should teach
about the scientific controversy that now exists over Darwinian
evolution.
This is simply good education. When credible
experts disagree about a controversial subject, students should
learn about the competing perspectives.
In such cases,
teachers should not teach as true only one view - just the Republican
or the Democratic view of the New Deal in a history class, for
example. Instead, teachers should describe competing views to
students and explain the arguments for and against these views as
made by their chief proponents. We call this "teaching the
controversy."
But is there really a scientific, as opposed to
just a cultural or religious controversy, over evolution? In fact,
contrary to recent mainstream media reports, there are significant
scientific controversies about key aspects of evolutionary
theory.
First, some scientists doubt the idea that all
organisms have evolved from a single common ancestor. Why? Fossil
studies reveal "a biological big bang" near the beginning of the
Cambrian period when many major, separate groups of organisms or
"phyla" (including most animal body plans) emerged suddenly without
clear precursors. Fossil finds repeatedly have confirmed a pattern
of explosive appearance and prolonged stability in living forms -
not
the gradual "branching-tree" pattern implied by Darwin's common
ancestry thesis.
Other scientists doubt the creative power of
the Darwinian mechanism. While many scientists accept that natural
selection can produce small-scale "micro-evolutionary" change in,
for example, the shape of finch beaks, many biologists now doubt
that natural selection and random mutations can generate the
large-scale changes necessary to produce fundamentally new
structures and forms of life. Small-scale micro-evolutionary changes
merely utilize or express existing genetic information ; the
large-scale macro-evolutionary change necessary to produce new
organs or body designs requires entirely new genetic
information.
Not surprisingly, some 350 scientists, including
researchers from MIT, Yale, Rice and the Smithsonian, have signed a
statement questioning the creative power of the natural selection
/mutation mechanism.
Finally, some scientists doubt the
Darwinian idea that living things merely "appear" designed. Instead,
they think that living systems display telltale signs of actual or
"intelligent" design. Prominent scientists, like former San
Francisco State University biophysicist Dean Kenyon and Lehigh
University biochemist Michael Behe, have cited intriguing evidence
in support of this theory: the presence of digital information,
complex circuits and miniature motors in living cells.
Behe,
for example, examines the rotary engine that powers the
propeller-like tails of certain bacteria. These machines - with their
rotors, stators, Orings, bushings, U-joints and drive shafts
- require the coordinated interaction of some 40 protein parts. Yet
the absence of any one of these parts results in the complete loss
of motor function. To believe this engine emerged gradually in a
Darwinian fashion strains credulity, Behe argues. Natural selection
only selects functionally advantageous systems. Yet the motor has no
function until after all 40 parts have been assembled. Thus, natural
selection can "select" or preserve the motor once it works, but it
can do nothing to help build the motor before then. Behe concludes
that a designing intelligence played a role.
Recently,
mainstream academic publishers, notably Cambridge University Press,
have published books and articles that present the scientific case
for, and the debate over, intelligent design.
Since
intelligent design is a new theory of biological origins, we
recommend that students not be required to learn about it.
Nevertheless, we think they should learn about the scientific
strengths and weaknesses of orthodox Darwinism. Clearly, teachers
should also be free to tell their students about alternatives like
Behe's design theory, provided such theories are based (as Behe's is)
upon scientific evidence, not biblical passages.
There are
many reasons to adopt this "teach the controversy"
approach.
First, constitutional law permits it. In the
controlling Edwards v. Aguillard case, the Supreme Court ruled that
state legislatures (and by extension state boards) already have the
right to mandate teaching scientific critiques of prevailing
theories. Interestingly, the court also determined that teachers
have the right to teach students about "a variety of scientific
theories about origins... with the clear secular intent of enhancing
science education."
Second, federal education policy calls
for it. The authoritative report language accompanying the No Child
Left Behind act states that "where topics are taught that may
generate controversy (such as biological evolution), the curriculum
should help students to understand the full range of views that
exist."
Third, polls show that over 70 percent of the
electorate nationally favors teaching the evidence both for and
against Darwin's theory of evolution.
Finally, teaching
scientific controversies engages student interest and encourages
them to do what scientists do - deliberate about how best to
interpret evidence. Italian philosopher of science Marcelo Pera has
shown scientific understanding advances through a process of
argument between advocates of competing ideas. Or as Darwin wrote in
his "Origin of Species," "A fair result can be obtained only by
fully stating and balancing the facts and arguments on both sides of
each question."
[2005/01/29] Teach Scientific Controversy About Origins of Life
