Expanding the Boundaries of Science

An article by two physicists, Adam Frank and Marcelo Gleiser in the NYT, suggests that science is experiencing an identity crisis. It used to be assumed that what distinguished science from other disciplines was that science was based on testing predictions which were entailed by a theory. This was called the hypothetico-deductive method.

Unfortunately, it seems that some theories in physics and biology have reached the limits of testability. In particle physics, for example, in order to probe more deeply into the structure of matter we have to build particle accelerators that would circle the earth.

Since this is economically and, presumably, technically impractical, particle physics may have reached a dead end. It's not that we know everything there is to know, it's that we may have reached a point where we know everything which can be known, at least about particle physics.

Rather than submit to this glum state of affairs, however, some scientists want to expand the boundaries of legitimate science to include metaphysical speculation. The problem of discerning what to count as science is called by philosophers the Demarcation Problem, and the tendency to blur the lines between science and philosophy (metaphysics) is especially prominent among string and multiverse theorists. Here's part of what Frank and Gleiser have to say about this:

A few months ago in the journal Nature, two leading researchers, George Ellis and Joseph Silk, published a controversial piece called “Scientific Method: Defend the Integrity of Physics.” They criticized a newfound willingness among some scientists to explicitly set aside the need for experimental confirmation of today’s most ambitious cosmic theories — so long as those theories are “sufficiently elegant and explanatory.”

Despite working at the cutting edge of knowledge, such scientists are, for Professors Ellis and Silk, “breaking with centuries of philosophical tradition of defining scientific knowledge as empirical.”

Whether or not you agree with them, the professors have identified a mounting concern in fundamental physics: Today, our most ambitious science can seem at odds with the empirical methodology that has historically given the field its credibility.

[This raises] a philosophical question: How are we to determine whether a theory is true if it cannot be validated experimentally? Should we abandon it just because, at a given level of technological capacity, empirical support might be impossible? If not, how long should we wait for such experimental machinery before moving on: Ten years? Fifty years? Centuries?

Consider, likewise, the cutting-edge theory in physics that suggests that our universe is just one universe in a profusion of separate universes that make up the so-called multiverse.

This theory could help solve some deep scientific conundrums about our own universe (such as the so-called fine-tuning problem), but at considerable cost: Namely, the additional universes of the multiverse would lie beyond our powers of observation and could never be directly investigated.

Multiverse advocates argue nonetheless that we should keep exploring the idea — and search for indirect evidence of other universes.

Similar difficulties seem to be looming in cosmogeny (the study of the origin of the universe), the origin of life and the origin of consciousness, all of which confront researchers with this awkward question: If scientists yield to the desire to include in the discipline of science explanatory theories which are inherently untestable and which are essentially metaphysical, on what grounds can anyone argue against allowing the teaching of Creationism in public school science classes?