To my mind what is significant about the idea of a Third Culture and a New Humanism has little to do with a split between academic humanists and scientists. That was the old First/Second culture debate, and there is no need to rehash it. The point I think John is making, and the point that I think is worth discussing is the extent to which that old split has been transcended by the work of some scientists and humanists over the last few decades. I believe that it has, and the reason is that there has been a turn in the kind of questions people are asking across a broad range of fields, and—even more importantly—there has been a shift in what kinds of answers scientists, social scientist and humanists have been searching for in their work. This shift, which I will characterize in a moment, is what characterizes the Third Culture and New Humanism, and it is also why these movements are able to resolve the old disputes between First and Second Culture scientists and humanists.

Thus, what Third Culture and New Humanist intellectuals have to offer society is far more than just being in touch with science. They represent the vanguard of a broad intellectual movement that already has representatives in diverse fields of the sciences, social sciences and humanities.

I think the deepest characterization of this new movement is epistemological, because it is about the kinds of questions people are asking and the kinds of answers they are searching for. It is indicated by the emergence of new styles of explanation which reject the notion of an eternal "ultimate reality" perceived by God alone in favor of more rational and accessible styles of explanations. The old style explanation relies on the hypothesis that behind the ever changing appearances there is an "ultimate reality" that is eternal and unchanging. This eternal reality may be God, it may be eternal principles of justice or aesthetics, or it may be the ultimate laws of nature. The new style of explanation rejects such ideas as being in the end little different from mysticism, as the alleged "ultimate reality" is unknown and unknowable. As pointed out by C. S. Peirce, any explanation that rests on an appeal to the existence of ultimate and unchanging eternal laws of nature is fundamentally irrational, because there can be no further explanation of why those laws of nature, rather than some others, hold. Such an explanation is logically no different than an appeal to "the mind of God."

The new style of explanation rejects the Platonic myth of an eternal realm of true ideas in favor of the idea that knowledge has no meaning apart from what humans beings, as part of the natural world, can perceive and agree on. It also rejects the transcendent fantasies according to which scientist used to picture themselves outside of reality and outside of any society, in the place of God, surveying all that exists without being a part of it. Instead, many scientists are now happy to see ourselves as individuals who work inside of communities of living beings, who seek knowledge by sharing their observations and debating their ideas.

At the same time, this new style of explanation is neither relativist nor irrational. It believes that there is a truth to things, and that human beings are capable of finding it. It is just rejects as irrational mythology the idea that truth is possible because of the existence of an imagined platonic realm of eternal, absolute ideas. Instead, this new movement grounds the notion and possibility of truth on the ability human beings have to argue rationally and in good faith from shared evidence and, by doing so, to arrive at agreement. To accept this is to accept also the notion that rationality is situated and pluralistic. By accepting that there will be things that appear differently from different viewpoints, we strengthen the importance of those things that we find we can agree on.

A contributing factor to this shift is that our cosmological picture has changed drastically, in a way that makes the search for an eternal "ultimate reality" incoherent. Relativity and quantum theory tell us that science must be based on relational quantities, that have to do with relationships between things in the universe, and that no appeal to anything transcend or eternal or otherwise outside the universe is possible, or even meaningful. Observations tell us that we live in a young universe, that was born a relatively short time ago, and has been evolving ever since. It is far from clear what eternal laws of physics can mean, when the universe itself is only a few billion years old.

An aspect of this is the attitude towards reductionism. Everyone can agree that when something is made of parts it is of course useful to explain it in terms of its parts. This is fine but the problem is that there is a natural limitation to how far such a reductionist explanation can be pushed. When it succeeds, reductionism must lead to an explanation in terms of some set of elementary particles and forces. But then there is a problem, because if the elementary particles are truly fundamental their properties cannot be explained by a further appeal to reductionism. So the question of why these fundamental particles and laws, and not others, must be answered in some way that is not itself reductionist. So if we truly want a rational understanding of why things are as they are, and not otherwise, we must follow the path of reductionism till we find out what the fundamental parts are, but after this we must find new, non reductionist modes of explanation.

Once a science reaches the point where naive reductionism can take us no further, there are three moves one can make. The first is of course to deny the existence of a crisis with reductionism and continue in a hopeless search for the eternal "ultimate reality". Unfortunately, this characterizes some, but by no means all, recent work in fundamental physics. Physicists who align themselves with the "many worlds interpretation of quantum mechanics, "eternal inflation" or who believe that theoretical physics is about to end with the discovery of "M theory" are operating from what may be called a "nostalgia for the absolute." There are similar, nostalgic movements in other fields.

The second response is what can be called the postmodernist move. This begins by denying the use of reductionism and the importance of rational understandings altogether. Truth is held to be nothing but a social construction, and a thorough going relativism is embraced. This is even worse than the nostalgic response, because it undermines the very reasons for the crisis, and leaves us suspended in an impotent haze from within which we cannot even remember how useful rational thought has been for improving our world, politically, scientifically and humanly. Even more than that, the postmodern ideology sabotages the possibility for democracy, because it denies the possibility that people in different situations, with different points of view, can argue rationally on the basis of shared evidence and reach agreement and mutual understanding.

There is however, a third, progressive response to the crisis in the search for "ultimate reality." This is to accept the strengths and limitations of reductionism and to seek to go beyond it to a more comprehensive and powerful kind of explanation. Evolution by natural selection is a paradigmatic example of such a theory: it is consistent with reductionism, but transcends it in being ultimately historical and allowing causation to go both ways-from the more to less complex, and the reverse. By attributing order to self-organization rather than design from the outside, evolution by natural selection offers an essentially rational mode of understanding that avoids any mystical appeal to eternal "ultimate causes of things."

Another characteristic of such explanations is that they may be applied to whole systems, which contain both all their causes and all their observers. Such whole systems include the universe, societies and ecologies. This implies that there is no useful view from outside the system, instead description and explanation are both pluralistic and relational, because they must take into account that any observer is situated inside the system. Thus, rather than denying objectivity, this kind of approach rationalizes it, by rooting objectivity in what may be observed from many, distinct view points, rather than in a mythical appeal to an "ultimate reality or an imaginary viewpoint from outside the system. This makes possible both science—that is knowledge without appeal to authority—and democracy in a pluralistic, multi-ethnic society.

This new kind of explanation characterizes much of modern biology, as well as recent approaches to complex and self-organized systems, whether economic, sociological, physical or biological. Into this category also goes new approaches to the foundations of quantum mechanics, which have been called relational quantum theory and new approaches to explanation in cosmology, such as cosmological natural selection, the notion of internal observables, and varying speed of light cosmologies.

I believe that what John has called the Third Culture and the New Humanism is ultimately rooted in this pluralistic, relational approach to knowledge. It characterizes many (although of course not all) of the thinkers that were interviewed in the Third Culture book. But the divide between the older, absolutes-seeking styles of thought and the newer, pluralistic and embodied, relational approach does not run cleanly between the sciences and the humanities. Many of the key debates now animating science are between specialists whose philosophical predilections put them on either side of this divide. The debates between many worlds and relational approaches to quantum mechanics or between string theorists and loop quantum gravity theorists clearly reflect this larger debate. So do the debates in evolutionary theory about the level and mechanisms of natural selection and the debates among computer scientists concerning the possibility of strong artificial intelligence. At the same time there are artists, philosophers, scholars, architects and legal theorists whose work is an exploration of the implications of the new attitude towards knowledge. Among them one can mention legal theorists such as Roberto Unger and Drucilla Cornell and artists and writers as diverse as Brian Eno and Pico Iyer.

Finally, it must of course be mentioned that what I have called a new approach to knowledge has very old roots. The 17th Century philosopher Leibniz was keenly aware that the world is a system of relations and the American pragmatists such as Peirce were already a century ago confronting the implications of Darwinism for epistemology and philosophy in general. (Indeed, the simplest way to divide Old from New Humanists is to ask whether their writing shows an awareness of how radically Darwinian evolution changes the background for doing new work in philosophy.) But Leibnizs worldview was to a large extent put aside in favor of Newtonian physics, until it was revived in the 20th Century, while the pragmatists have not had the influence of the deconstructionists in the American academy. When graduate students in the humanities embrace Peirce and Dewey, rather than Foucault and Derrida, and when they read Darwin rather than Hegel, we will be able to say that the New Humanism has come of age.

LEE SMOLIN is a theoretical physicist and a founding member at the Perimeter Institute in Waterloo Canada. And author of Three Roads to Quantum Gravity. [more....]