When I was fresh out of graduate school and working as a particle physicist about 27 years ago, I began writing a book to be titled: The End Of Discovery. My point was very much the same as what I glean from reports of John Horgan's recently published The End Of Science . That is that all the major basic, revolutionary discoveries that are possible -- to the extent they matter to ordinary people at all -- have already been made. The fact that one could make an argument 27 years ago, and then make the same one now, while from many viewpoints the intervening years can be considered scientifically quite fruitful doesn't make the argument wrong. But it should give us some pause.
I think we are not at the end at all. But I also think that science will change considerably in its entire focus and outlook over the next century. One reason there will still be endless discovery is that the argument that there won't be rests on a deeper argument -- reductionism. I think it is mistaken. In the rest of this essay, I outline why.
The reductionist argument is that there is some simple unified set of principles that explains everything in the world, and on which any other explanation must rest. The most common contemporary kind of reductionism is the idea that everything is made of the same particles (say, quarks and leptons) held together by the same forces. (In the current theory particles and forces would both be replaced by quantum fields, which are taken to be even more basic, or locally conserved currents, yet more basic, or "strings," which if accepted would be still more basic. And so on.)
Properly understood, the theory of emergent levels is counter to reductionism. It concedes that yes, in a certain way everything may be said to be built of matter and obeys its most basic laws, but there are higher kinds of structures that have laws of their own, laws that would be unchanged were the underlying particles -- or whatever -- to be different. The so-called basic laws are of less and less importance at higher levels.
As an example of emergent properties, consider shapes. The basic particles of the world can be viewed as points or at most spheres or cylinders, insofar as they can be said to have shapes at all. Yet if you combine enough of them together, the simple forces that bind them still end up letting them assume the quite complex shapes of biological molecules such as DNA, transfer RNA, enzymes, hormones and neurotransmitters, among many others. While it may be that each particular species of molecule has the shape it does only because of the nature of the underlying forces, the way shapes themselves fit or don't fit into one another is independent of how these shapes are composed. Thus, the underlying particles and forces might be quite different from what they are, and still they could allow shape- dependent forms of life to exist much as now.
Thus, in contemporary pharmacology, shape assumes an importance of its own. It is often possible to mimic the shape of part of a bioactive molecule by some other molecule with a quite different composition. Like a key fitting into a lock, what matters here is how the different shapes fit together, not how that shape is made possible by any specific combination of components and forces.
Another example concerns human economic systems. Every economy works according to its own laws, and those laws would be much the same regardless of what humans happen to be made of, how big they are, or other particular details about the construction or even the motivation of individual human beings. In a money economy, for example, there is a law of supply and demand; why could it not still hold true if humans had six arms and scales, or if we were made of something other than carbon molecules, or if the more basic particles were not quarks but something quite different?
Another emergent system is language. For language to work it has to have certain general properties, apparently. (For instance there have to be terms that can be understood to be the same, even when spoken by different people. We have no reason to believe that when you read the words "white rose" that the same neurons would fire in your head as in mine or some third person's, or that such an exact identification would be at all necessary in order for us to agree on the meaning of the expression or the parts of speech involved.
One might also try to describe words as made up of something simpler -- sounds. But that's not true in the case of written or printed words, and yet very much the same thought can be conveyed in spoken or written words, often. Nor among spoken words is it at all true that a given word, even if it appears in exactly the same usage in the same sentence, would be defined the same every time.
Thus, for each level of structure, even though that structure to some extent can rest on simpler underlying structures, there is a separate law, a law that would be the same regardless of what the underlying components might be, and a law that cannot possiby be deduced just from considering the underlying components.
Furthermore, shape, economics and language are but three emergent levels among what we have every reason to believe could be an infinity of levels, each with their own special ways of working -- rules if you wish.
Some of these levels presumably don't yet exist, just as there was a time before molecular shape was important, or before language, or before economic systems, etc. Nor should we believe that these rules in any meaningful way exist in advance. Knowing that there are economic systems, we can hope to think about the problems of the interactions of intelligent beings who are capable of effort and have desires interacting and try to describe different possible successful or quasi-successful arrangements, but we are unlikely to think of all the possible ways economies might work in advance. So, in practice it would seem a new economy would have to come into being, and only then could we begin to determine what type it is and what specific "laws," if any, it follows.
All of this means that in no real way can we ever do what graduate students in physics in my generation-- the 1960s-- used to dream of -- "solving the universe." No matter how much we may know, we are in for future surprises. Because these surprises will definitely make significant differences in human life, it would be quite misleading to characterize them as unimportant or of somehow lesser importance, lesser status than say the knowledge of quarks.
Because we believe we understand our world at every given moment, a discovery of a newly emergent level and the laws pertaining to it has to come as a surprise every time. So it can have all the shock value, all the revolutionary intensity and excitement of a discovery such as those of Copernicus, Newton, Darwin, or any of the other biggies. (Two recent examples: the invention or discovery of feminist principles and the fall of Communism both have proved to be giant intellectual shocks, shocks that can reverberate into the future just as much as the discovery of evolution or the quark.)
-- Michael H. Goldhaber / mgoldh.@well.com /8/23/96/