I am pleased to be asked to participate in the Humanists of Houston conference on "Religion, Humanism, & Science in the 21st Century," [April 2000] because of my membership in IRAS, the Institute on Religion in an Age of Science. First a disclaimer: I hold no office in IRAS or any of the other organizations to which I belong, and I cannot claim to speak for any of them, not IRAS, not CSICOP (Committee for the Scientific Investigation of Claims of the Paranormal), not the ELCA (Evangelical Lutheran Church in America), not the SEG (Society of Exploration Geophysicists). And I cannot be comprehensive in this short essay, but will simply focus on the American situation and the Judeo-Christian heritage.
To look ahead at the century before us, I'll first look back one hundred years at the views of religion advanced by Karl Marx, Sigmund Freud, Pope Leo XIII, and G. K. Chesterton. I'll follow trends through the 20th century to gauge where we are and where we're going, with examples from the current Pope and from Stephen Jay Gould. I have five predictions for the character of religion in the 21st century: it will continue; will be strongly religious; but will be transformed; will exhibit tolerance; but its diversity will remain messy. I see especially the traditional monotheistic religions developing a pan-orthodox relationship, able to live and work together on critical moral and political issues while not surrendering their orthodox teachings. As a Christian, I did not think of myself as a humanist before researching this presentation and being persuaded by The Case for Christian Humanism. I'll conclude that the future of religion is epitomized by post-critical orthodoxy, and that American political institutions are a good model for its civil context.
As an applied physicist in an industry which likes graphs that go up to the right, I'll organize my projection of the future of religion around the familiar extrapolation of a graphed quantity, by looking back to discern the direction of trends to where we are at present, and expecting continuity into the future, a future that I expect will bring established religions into a pan-orthodox relationship.
Since we're looking forward at the 21st century, looking back about 100 years should set an appropriate time scale. Deterministic extrapolation was in tune with the times 100 and more years ago, for example Laplace's claim in 1773 that "... in order to determine the state of the system of these large [celestial] bodies in past or future centuries, it is enough for the mathematician that observation provide him with their position and speeds at any given instant."  So let us look for the position and speed of religion around the year 1900. I will use several selected quotes from critics and proponents of religion to take its pulse at the turn of the 20th century.
Karl Marx's well-known characterization of religion as "the opium of the people" dates from 1843. A further quote from his same essay is less well-known, but gives his prescription for the future of religion:
"The abolition of religion as the illusory happiness of men, is a demand for their real happiness. The call to abandon their illusions about their condition is a call to abandon a condition which requires illusions. ... The criticism of religion disillusions man so that he will think, act and fashion his reality as a man who has lost his illusions and regained his reason; so that he will revolve about himself as his own true sun. Religion is only the illusory sun about which man revolves so long as he does not revolve about himself." 
Sigmund Freud developed his psychology of the subconscious around the turn of the 20th century, and later wrote extensively on religion. In his 1927 book The Future of an Illusion Freud writes:
"Religion would thus be the universal obsessional neurosis of humanity; like the obsessional neurosis of children, it arose out of the Oedipus complex, out of the relation to the father. If this view is right, it is to be supposed that a turning-away from religion is bound to occur with the fatal inevitability of a process of growth, and that we find our- selves at this very juncture in the middle of that phase of development." 
Freud also wrote about the stages of this inevitable turning-away from religion:
"Humanity has in the course of time had to endure from the hands of science two great outrages upon its naive self-love. The first was when it realized that our earth was not the center of the universe, ... The second was when biological research robbed man of his peculiar privilege of having been specially created, and relegated him to a descent from the animal world, implying an ineradicable animal nature in him: this transvaluation has been accomplished in our own time upon the instigation of Charles Darwin, ..." 
In contrast to these critics of religion, let us look at some religious writing from about 100 years ago. Partly in response to the political and economic foment of the 19th century in which Karl Marx played a prominent part, Pope Leo XIII issued the Catholic Church's first social encyclical in 1891, titled "Rerum Novarum," which called for more honorable treatment of workers and all ordinary people, based on the church's traditional teachings. Orthodox religion too was being transformed:
"1. That the spirit of revolutionary change, which has long been disturbing the nations of the world, should have passed beyond the sphere of politics and made its influence felt in the cognate sphere of practical economics is not surprising. The elements of the conflict now raging are unmistakable, in the vast expansion of industrial pursuits and the marvelous discoveries of science; in the changed relations between masters and workmen; in the enormous fortunes of some few individuals, and the utter poverty of the masses; in the increased self-reliance and closer mutual combination of the working classes; as also, finally, in the prevailing moral degeneracy." 
The case for Christian orthodoxy is advanced by G. K. Chesterton in his 1908 book titled Orthodoxy:
"The Church had to be careful, if only that the world might be careless. This is the thrilling romance of Orthodoxy. People have fallen into a foolish habit of speaking of orthodoxy as something heavy, humdrum, and safe. There never was anything so perilous or so exciting as orthodoxy. ... The Church in its early days went fierce and fast with any warhorse; yet it is utterly unhistoric to say that she merely went mad along one idea, like a vulgar fanaticism. She swerved to left and right, so exactly as to avoid enormous obstacles. She left on one hand the huge bulk of Arianism, buttressed by all the worldly powers to make Christianity too worldly. The next instant she was swerving to avoid an orientalism, which would have made it too unworldly. The orthodox Church never took the tame course or accepted the conventions; the orthodox Church was never respectable. ... To have fallen into any one of the fads from Gnosticism to Christian Science would indeed have been obvious and tame. But to have avoided them all has been one whirling adventure; and in my vision the heavenly chariot flies thundering through the ages, the dull heresies sprawling and prostrate, the wild truth reeling but erect." 
Chesteron presents orthodoxy as the most freewheeling of free thinking, a vision I think should be more widely shared.
Summarizing the situation 100 years ago, critics of religion prescribed its immanent demise in the light of science, whereas religious leaders saw fulfillment of traditional teachings and exciting opportunities ahead.
Let us now move quickly forward to our own day, and look at what trends can be seen on the way to the present. The straightforward 19th century vision of progress was soon shattered by the First World War, and the Communist revolution in 1917 established the first determinedly antireligious state. Nazism and fascism launched a more virulent replacement for traditional religion, and tried to exterminate the Jews. Following the Second World War, the Soviet leader Josef Stalin asserted control over Catholic Poland with the words "Mr. Churchill, Mr. Prime Minister, how many divisions did you say the Pope had?"  This arrogant rejection of religion came in the midst of Communism's own humanitarian train wreck, which would leave perhaps 100 million dead by the end of the century, an order of magnitude more than Nazism.
Despite the Cold War, the second half of the century was
more hopeful. Science and technology made great advances throughout the
century. The determinism of physics stated so clearly by Laplace was modified
by relativity and quantum mechanics, and in mathematical logic Godel's incompleteness theorem deflated philosophical
positivism. Molecular biology revealed the structure of DNA and the material
substrate of life, putting Darwin's theory of evolution by natural selection on
a firm scientific footing. Technology blossomed, with aviation, radio, television,
and digital computing building on older technologies for transportation and
communications, and connecting the whole world in a cultural process of
globalization. The human population grew exponentially, and urbanization
encompassed most of humanity, sweeping away traditional lifestyles.
Secularization grew in modern culture, and ethnic and cultural diversity mixed
together people and ideas at an unprecedented pace and scale.
Religion too was transformed in this dynamic century, but not in the way prescribed by Marx and Freud. Catholic Poland threw off the chains of Communism, and Marxist ideas are burdened with the Soviet legacy. The Catholic church threw open the windows and let in fresh air with the Second Vatican Council. Pope John Paul II celebrated the 100th anniversary of "Rerum Novarum" in 1991 with a second social encyclical, "Centesimus Annus":
"I now wish to propose a 'rereading' of Pope Leo's encyclical by issuing an invitation to 'look back' at the text itself in order to discover anew the richness of the fundamental principles which it formulated for dealing with the question of the condition of workers. But this is also an invitation to 'look around' at the 'new things' which surround us and in which we find ourselves caught up, very different from the 'new things' which characterized the final decade of the last century. Finally, it is an invitation to 'look to the future' at a time when we can already glimpse the third millennium of the Christian era, so filled with uncertainties but also with promises--uncertainties and promises which appeal to our imagination and creativity, and which reawaken our responsibility, as disciples of the 'one teacher,' to show the way, to proclaim the truth and to communicate the life which is Christ." 
Rather than humanity accepting mere animal status as prescribed by Freud's second stage of growth, a different second stage has emerged among religious intellectuals, which Paul Ricoeur has termed "second naiveté."  This is not senility, in the way the term "second childhood" is sometimes used, but is rather a recognition, once one has learned the scientific facts of life and understood the criticisms of the religious heritage, that nevertheless religion truly and uniquely carries what is significant about our life and world and future. Rather than diminishing or destroying religion, modern criticisms have refined it and let religious intellectuals again celebrate orthodox religion in a spirit of "post-critical naiveté," to use theologian Marcus Borg's  formulation of the term.
Literalists are appalled by this sort of religious sophistication. Religious fundamentalists denounce it as a sly way for educated atheists to mislead ordinary folks by appearing in sheep's clothing, practicing religion on the outside but doing the devil's work within. Secular literalists are equally distressed. For example, Stephen Jay Gould writes:
"Physical reconstruction, the first step in a Freudian revolution, has been accomplished: all thinking people accept the biological fact of our 'descent from the animal world.' But the second stage, mental accommodation toward pedestal-smashing, has scarcely begun. Public perception of evolution has been so spin doctored that we have managed to retain an interpretation of human importance scarcely different, in may crucial respects, from the exalted state we occupied as the supposed products of direct creation in God's image." 
Gould wants to knock humanity off this pedestal, which doesn't seem like humanism to me.
From this context, what kind of future can we expect for religion in the 21st century? First, I think we should expect continuity -- religion gives expression to our innate spirituality, has been around as long as humanity, and major religions can claim many centuries of history, so we should expect religious centuries ahead. Second, or perhaps a corollary, is that religion will be religious -- Marx and Freud were mistaken a century ago about the fading of religion. Rather than the "religion lite" of liberal theology, I expect robust religion in the future, determined by the leadership of devoutly religious people finding strength in orthodoxy. Third, religion will be transformed, even as it has been in the 20th century -- we can expect Muslims and others to follow Jews and Christians through the transition to the "post-critical naiveté." Fourth, the "post-critical" religions will be mutually tolerant, driven toward humanism by modern, mutual critique. Fifth, religion will be messy, with historic religious diversity and schism continuing to be fragmented by the dynamic cultural trends built on interactive electronic communication. Religion is not one thing, but comes in many varieties, and we can expect many more.
The point I find most interesting is the fourth, predicting mutual respect, cooperation, and even fellowship among the mature, orthodox religions, especially among their most devout leaders. This idea crystallized for me when I read a short essay by Robert P. George, a professor of jurisprudence at Princeton, in the January 2000 issue of First Things. He says:
"One thing seemed certain [35 years ago]: the ecumenical action would be on the left wing of the various religious communities, not on the right. Traditional Catholics, conservative Protestants, and observant Jews were viewed as part of the problem, not part of the ecumenical solution. After all, interfaith dialogue would require 'flexibility,' 'openness,' 'tolerance'—virtues of the religious and sociopolitical left (it was supposed), not the right. Indeed, the 'rigidity,' 'dogmatism,' and 'authoritarianism' of conservative religious believers would (it was thought) make them obstacles to the dialogical enterprise. Ecumenism would have to proceed despite anticipated conservative resistance. Then came the culture war. ... Today, traditional Catholics, Eastern Orthodox Christians, evangelical and other conservative Protestants, and believing Jews are not only working, but praying, together. Interfaith cooperation in pursuit of operational objectives in the culture war (e.g., banning partial-birth abortion, preserving the institution of marriage) has occasioned the emergence of genuine, and unprecedented, spiritual fellowship." 
I expect this pan orthodoxy to encompass not just Judaism and Christianity, but not to be so wide as to include all religions. The monotheistic religions have common ground, and I expect Islam will go through the post-critical transition. Established Eastern religions may fit too, but there will likely always be problematic religious movements that are rightly opposed by true humanists.
And now to the future of religion and humanism in the 21st century. I must admit that I did not think of myself as a humanist before beginning to work on this essay: I believed those secularists who try to make secularism synonymous with humanism, and their fundamentalist critics who condemn humanism and secularism without distinction. But in the course of my research I found a wonderful book, The Case for Christian Humanism, by R. William Franklin and Joseph M. Shaw , who point out that Christianity is necessarily humanistic, that modern humanism emerged from the Judeo-Christian heritage, and that faithful Christians have much common ground with even secular humanists. Indeed this common ground is key to the pan-orthodox future, as post-critical religious intellectuals and other leaders can realistically assert that our human destiny is most fully fulfilled within a particular religious tradition, without risk of inhuman strife. In the United States, this mutual self-respect is enhanced, even enabled, by the First Amendment, which protects all particular religions from domination by government, and guarantees civil public space where any particular religion can contend for attention without risk of violence. Let us hope that our courts will interpret the constitution wisely, to let American religion be a shining light to the world.
I have addressed the future of religion in the 21st century, particularly in the context of the United States and the Judeo-Christian heritage. I used examples from 100 years ago to compare to the present and identify trends for the future. I made five predictions about religion in the 21st century: it will have continuity, be religious, be transformed, be tolerant, and be a mess. Especially I see a pan-orthodox future, with different religions emerging from a post-critical transition to interact with civility, and share some common causes even as they contend for the hearts and minds of humanity. And I see a common element of humanism, modeled on the American experience, leading the way.
Essay version 2000 May 05, after presentation 2000 Apr 16
1. Quoted in Roger Hahn, "Laplace and the Mechanistic Universe", p. 269 in David C. Lindberg and Ronald L. Numbers (ed.), God and Nature: Historical Essays on the Encounter between Christianity and Science, U. of California Press, 1986.
2. From "Marx on the History of His Opinions", p.12 in Robert C. Tucker (ed.), The Marx-Engels Reader, W. W. Norton, 1972.
3. From p. 43 in Sigmund Freud, The Future of an Illusion, tr. and ed. James Strachey, published in German, 1927, Norton, 1961.
4. From Sigmund Freud, General Introduction to Psycho-Analysis ,18th Lecture, quoted at http://www.san.beck.org/Soul-Contents.html.
5. Full text of Papal encyclical "Rerum Novarum" online at http://www.ewtn.com/library/ENCYC/L13RERUM.HTM.
6. From p. 305-306 of G. K. Chesterton, Orthodoxy , in Collected Works I, Ignatius, 1986.
7. Stalin quote from http://www.wizvax.net/hotspur/QuotesS.html.
8. Full text of Papal encyclical "Centesimus Annus" online at http://www.ewtn.com/library/ENCYC/JP2HUNDR.HTM.
9. Paul Ricouer's work discussed in Philip Hefner, The Human Factor: Evolution, Culture, and Religion, Fortress Press, 1993.
10. Marcus Borg's bio and references online at http://westarinstitute.org/Fellows/Borg/borg.html.
11. From p. 326, Stephen Jay Gould, 1995, "Can We Complete Darwin's Revolution?" in Dinosaur in a Haystack, Harmony Books.
12. Robert P. George, in What Can We Reasonably Hope For?, A Millennium Symposium, First Things #99 p22; 2000-Jan. Online at http://www.firstthings.com/ftissues/ft0001/articles/rgeorge.html.
13. R. William Franklin and Joseph M. Shaw, The Case for Christian Humanism, Eerdmans, 1991.