Can Science Explain Everything?
Is science complete and unitary? Does it offer an overarching and all-inclusive description of reality, reaching from the foundations of space-time to the self-illuminating capacities of consciousness? This question strikes at the heart of much of the debate between science and religion as atheists argue that the explanatory powers of science make religion irrelevant. Stepping beyond the forever-contentious arena of science vs. religion, the question of completeness stands at the center of hard-core philosophical debates about the nature of world and our access to it.
A couple of weeks ago my co-blogger Alva Noë raised the issue of the relationship between our experience of the world and the underlying reality science describes. Alva said that we are "confabulators," creating a world of odor, color and flavor where no such fundamental reality exists in the realm of fundamental particles upon which everything sits. Reading over Alva's provocative piece I was struck by another puzzle implied in his argument: can science explain everything as a seamless whole?
There are many different kinds of science: physics, chemistry, biology and sociology. Each discipline also breaks down into its own subfields. Physics is really particle physics (quarks, etc.), nuclear physics (nuclei), condensed matter physics (the study of aggregates of matter like solids), quantum optics (the study of light) and astrophysics (to name a few). The common narrative of science is that one can begin at the bottom in a field and work up to the top. If you know the foundational laws of a field then you should be able to work up, level by level, to first embrace the sub-disciplines and, eventually, end up with a complete, coherent account of all phenomena. This reductionist vision is dominant in science and we discuss it frequently here at 13.7. Today, however, I'm interested in something different.
The question on the table today is more straightforward. Does the science we have now constitute anything like a unitary whole? How well do the theories governing one branch, or even one sub-discipline, of science make the transition into other domains? Does science comprise an explanatory pyramid of universal laws built from a broad, solid foundation, or is it a collection of smaller relatively separate temples, each dedicated to some smaller piece of the world?
Glory be to God for dappled things -
For skies of couple-color as a brindled cow;
For rose-moles all in stipple upon trout that swim;
Fresh-firecoal chestnut falls; finches wings.
In her book The Dappled World, A Study of the Boundaries of Science Cartwright argues directly from case studies of scientific practice. The "dappling" that interests her are the myriad models, theories and frameworks that make-up the day to day work of science. Attempts to create meta-theories that provide the scientific version of a God's eye view do not impress her. Truth is simpler she says:
The laws that describe this world are a patchwork, not a pyramid. They do not take after the simple elegant and abstract structure of axioms and theorems.
There is nothing wrong with the laws we have discovered, according to Cartwright. It is just that these laws exist within the more limited domains of the controlled experimental settings from which they were discovered. From Cartwright's perspective, the dappled world is no less powerful or beautiful than, in her mind, the hoped-for but illusory world of grand, overarching theories.
Philip Kitcher is another philosopher who doubts the grand theory view of science and reality. In a fascinating piece for The Stone, he uses Newton's laws to illustrate the uber-example of a grand theory:
Newton looked forward to a vision of the cosmos in which everything would be explained on the basis of a small number of physical principles. That Newtonian vision remains highly popular with many scientists who turn philosophical in their later years and announce their dreams of a final theory.
For Kitcher, however, the reality shown by the actual practice of science is more piecemeal. As he puts it:
Thinkers in the grip of the Newtonian picture of science want a general basis for general phenomena. Life isn't like that.
Molecular Biologists, for example, don't account for life but work to understand more limited (though still remarkable) functions of life. Kitcher's claim is that when scientists go from DNA to digestion they step through a vast ensemble of models. Each model or theory will, of course, be related to those around them. The mistake, says Kitcher, is to see them all as Lego blocks snapping together with perfect modularity and making a single unitary whole that we could call a theory of life. As Kitcher's sees it:
There are no grand theories, but lots of bits and pieces, generating local insights about phenomena of special interest.
The possibility that science only truly functions through local, patchwork descriptions seems to be one approach to the questions Alva posed two weeks ago. When I asked him about the issue, he responded:
It's gotta be right that there is no grand unified theory of everything. It may be possible to consolidate a lot of physics, but as soon as you turn to molecular biology, or engineering, or geology, not to mention anthropology and cognitive science, you need new principles and, as philosophers will say, "ontological commitments."
For myself, I came to be passionate about science as a young man for exactly the reason that it offered grand theories. In that way it seemed to provide a kind of rational alternative to religion and its dogmas. As I have gotten older, however, I have become more skeptical of grand claims (scientific or religious). While I'm not ready to embrace Cartwright's vision, I am convinced that the awesome power and beauty of science do not require grand theories.
What I do know is that contemplation of these alternatives to the usual narrative of science and theories of everything enlarges my own vision of the world.
What if it's not the way I've always supposed? What if our dreams of final theories are just that? What if the world is dappled for us? What if that is just a truth of being human? If so, then, there is just as much beauty in the shadows as there is in the light.