So far, my favorite response to the annual Brockman challenge – this year, the question was “What will change everything?” – comes from the physicist Stuart Kauffman:
Reductionism has reigned as our dominant world view for 350 years in Western society. Physicist Steven Weinberg states that when the science shall have been done, all the explanatory arrows will point downward, from societies to people, to organs, to cells, to biochemistry, to chemistry and ultimately to physics and the final theory.
I think he is wrong: the evolution of the biosphere, the economy, our human culture and perhaps aspects of the abiotic world, stand partially free of physical law and are not entailed by fundamental physics. The universe is open.
Many physicists now doubt the adequacy of reductionism, including Philip Anderson, and Robert Laughlin. Laughlin argues for laws of organization that need not derive from the fundamental laws of physics. I give one example. Consider a sufficiently diverse collection of molecular species, such as peptides, RNA, or small molecules, that can undergo reactions and are also candidates to catalyze those very reactions. It can be shown analytically that at a sufficient diversity of molecular species and reactions, so many of these reactions are expected to be catalyzed by members of the system that a giant catalyzed reaction network arises that is collectively autocatalytic. It reproduces itself.
Can we have a natural law that describes the evolution of the swim bladder? If a natural law is a compact description available beforehand, the answer seems a clear No. But then it is not true that the unfolding of the universe is entirely describable by natural law. This contradicts our views since Descartes, Galileo and Newton. The unfolding of the universe seems to be partially lawless. In its place is a radically creative becoming.
Let me point to the Adjacent Possible of the biosphere. Once there were lung fish, swim bladders were in the Adjacent Possible of the biosphere. Before there were multicelled organisms, the swim bladder was not in the Adjacent Possible of the biosphere. Something wonderful is happening right in front of us: When the swim bladder arose it was of selective advantage in its context. It changed what was Actual in the biosphere, which in turn created a new Adjacent Possible of the biosphere. The biosphere self consistently co-constructs itself into its every changing, unstatable Adjacent Possible.
If the becoming of the swim bladder is partially lawless, it certainly is not entailed by the fundamental laws of physics, so cannot be deduced from physics. Then its existence in the non-ergodic universe requires an explanation that cannot be had by that missing entailment. The universe is open.
Karl Popper famously distinguished between two types of scientific problems: clocks and clouds. Clocks are neat, orderly systems that can be elegantly solved through reduction. (Think, for instance, of planetary orbits, which can be explained with gravitational equations.) A cloud, on the other hand, is an epistemic mess; as Popper put it, they are “highly irregular, disorderly, and more or less unpredictable.” After all, clouds are carried and crafted by an infinity of currents; they seethe and tumble in the air, and are a little different with every moment in time.
The question, of course, is whether the universe (and all the life contained therein) is a clock or a cloud. The methodology of modern science is predicated on the assumption that everything is a clock, a wonderfully complex timepiece to be sure, but still a clock. But what if reality is a cloud? Is reductionism still valid? Or are clouds best solved through simple observation, induction and ad hoc theorizing? Of course, that’s how science was done in the 19th century (eg, Darwin), but maybe that’s our future?