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Positivism has both a narrow and an expanded definition. In its narrow definition, it describes the philosophy of the Vienna and Berlin Circles, which in the 1920's attempted to rationalize not just philosophy, but all the sciences, based on a strict set of rules. In its wider definition, positivism is the belief that all of science is a steady upward progress that can be assisted by following the rules. As a strict philosophy, positivism had a brief life in the first half of the 20th century, but its impact can still be seen in the religion vs science debates continuing up to today.

Vienna Circle

The philosophers that collected in Vienna in the 1920's included Moritz Schlick, who was asassinated by a Nazi in 1936, and it was the ascendance of the Nazi party which scattered his colleagues, Rudolf Carnap, Hans Reichenbach and Carl Gustav Hempl to America, where there influence was perhaps greater than in Europe. The Vienna circle began under the influence of Ernst Mach's (1838-1916) views on science and metaphysics, calling itself, "The Ernst Mach Society". Mach had been both a first-rate physicist and anti-realist, radical empiricist philosopher who disliked the Newtonian metaphysics. With Einstein's breakthrough of special relativity (and his lectures on what science really measures), there finally appeared to be a good reason to abandon Newton's metaphysics. For Mach, the error lay in assuming the existence of something we can't see or prove, Newton's insistence on absolute space and time. Thus to avoid Newton's errors, we must not allow ourselves to predict or believe in a "reality behind" the observations. Mach wanted to remove the dependence on metaphysics from the pursuit of science. For the Vienna circle, this desire was realized in the techniques and skills being developed by Russell among others in symbolic logic, and the new-found ability to subject language to the rigors of mathematics. With the principle at heart and techniques in hand, they began to construct what such a scientific, metaphysic-free, world would look like.

However, there are other motivating factors in the development of logical positivism. One factor is the belief that all the ills of the preceding centuries, and in particular, the ills caused by religion, were the result of bad metaphysics. Heaven and hell, for example, should be seen as unprovable constructs that must be abandonned in the name of good science. Furthermore, true heaven would be the concrete realization of peace and prosperity that resulted from scientific progress, the inevitable result of applying scientific methods to everyday life. Russell, a british philosopher who was part of the program, and also influenced the Vienna circle, wrote a book in 1927 entitled, "Why I am not a Christian", which clearly tied this philosophy to an atheistic world view. One way to view logical positivism is as an increasing secularization of science in the same spirit as Darwin; Kant's wall between religion and science became a shrinking boundary around a religious ghetto. To quote the internet encyclopedia of philosophy,
The basic tenets of logical positivism are that there are exactly 2 ways to know truth, and 1 false way:
  1. Analytic a priori: Math statements like 2 + 2 = 4.
  2. Synthetic a postiori: Science statements like "all crows are black"
  3. Synthetic a priori: Science statements like "Invisible atoms are responsible for the laws of gases (PV=nRT).
A statement has meaning if and only if one can logically verify it. Since synthetic a priori cannot be verified, they have no meaning. By detecting and removing the false synthetic a priori, we can purge our science and religion of all sorts of outdated and dangerous concepts like "souls" or "God". Unfortunately, there were a number of problems with this view, because lots of useful theories could never be based on these two acceptable techniques. That is, one cannot prove that all of math is based on step-by-step construction of a priori truthful statements. There were some perfectly reasonable mathematical statements that were neither true nor false. Nor is it fair to dismiss most accepted models in science, just because they use a synthetic a priori.

The Vienna circle influenced people like Kurt Goedel, Karl Popper, and Ludwig Wittgenstein who all responded to its siren song in different ways. Popper, for example, argued with the Vienna circle about their "verification" principle, saying that it was more accurate to say that a model should have ways to falsify it. E.g., a Freudian theory that always explained everything in the end explained nothing. Better a theory that delimited itself by saying in effect "if you make this observation then my theory is false." Popper attributes this insight to Einstein, who said the 1919 eclipse expedition was a chance to falsify his theories. (Curiously, this aspect of positivism has been used against Evolution for being a unfalsifiable theory, to which proponents sniff that this is "Popper chopping".) Even this rescusitation was too limiting, and in the end, no philosopher of science today will attempt to defend strict positivism.

Characteristic of this change, Ludwig Wittgenstein, Bertrand Russell's brightest student, wrote a very significant support of positivism known as the Tractatus Logico-Philosophicus in which he delineates the project of positivism in terms of language. But a few years later after attempts to build such a world view, he reverses himself in The Blue and Brown Books" and his posthumous Philosophical Investigations in which he argues that truth cannot be so easily confined in language, rather it is localized to the little world under discussion, or "language game". This conclusion founded the field of "analytic philosophy" wherein philosophers no longer attempt to find absolute truth, but uncover the rules of a particular language game.

Kurt Goedel, who came to Princeton during WWII, wrote a mathematical proof using symbolic logic, illustrating why ambiguity was unavoidable. This was a great blow to the program. For years, Russell and Whitehead had been collaborating on an encyclopaedia " Principia Mathematica which intended to demonstrate that all mathematics could be based on the simple Peano assumptions plus logic alone. But can logic always determine the truth of a mathematical statement? Russell gives the brain puzzler "Suppose in a certain small town there is a barber who shaves everyone who does not shave himself. Who shaves the barber?" (My favorite answer is "She doesn't need to.") One can distill that story into the proposition "This statement is false." Is that a true or false sentence? Russell goes to great lengths to exclude such nonsense from his philosophy, but Kurt Goedel's proof demonstrated that self-referential statements were the bane of logic, and could never be excluded. i.e. if Russell will make a rule to exclude such statements, Goedel will include that rule in his new version. Thus any language Russell can invent will never be completely self-consistent, it can never categorically demonstrate the truth or falsehood of every theorem, it will be always incomplete, it will always need "outside help" to determine meaning. Douglas Hofstetter, in his book Goedel, Escher, Bach points out that self-referentiality has important consequences. For example, AIDS is a virus that infects the body's anti-virus machinery, with devastating results. We will discuss later in the course why self-referentiality has important theological ramifications as well.

One last story of the demise of positivism is worth telling. Rudolf Carnap came to America to escape the Nazis and had a long and successful career beginning at the University of Chicago. He persuaded a student, Thomas Kuhn, to write an article for the International Encyclopaedia of the Unified Sciences on scientific theory development, probably believing that it would illustrate the principles of logical positivism. Instead, Kuhn discovered that science progresses not at all logically, and his article became the book "The Structures of Scientific Revolution", which ironically sounded the death knell for an optimistic positivism view of scientific progress. That is, not only does positivism fail in principle, as Goedel and Wittgenstein argued, it failed in practice, as Kuhn showed.

Thus logical positivism failed to accomplish its noble goals of firmly establishing all of science and life on simple logic and observation. For many people including most scientists, this failure was percieved as a limitation of the tools, not of the stated goals. That is, the goal of secularization was still valid, only the approach required some more tinkering. If I can make a generalization, this reduced intensity positivism became a widespread article of faith in "materialistic naturalism" that finds so much expression in our schools and academies today. Contrast this view with that of Wittgenstein who completely forsook any attempt for logical proof of absolute truth. This paradox, that scientists continue to believe in the search for absolute truth while philosophers have abandonned it, lies at the heart of the dilemma facing the current, post-modern culture. Once again, it appears that epistemology is crucial to understanding our present impasse. Whether it be theology, science or philosophy, whether it be metaphysics or ethics, it appears that Pilate's question, "What is Truth?" remains basic.


Naturalism, or scientific materialism is a particular variety of scientific thought that is very popular in the 20th century. It incorporates a lot of mechanistic philosophy and is often very "deterministic" with a firm belief in "chance". In its relation to religion it comes in two forms, mild and virulent.

The milder version would say that religion is irrelevant for science, and possibly for life in general and society in particular. At my college, a traditionally fundamentalist school, my Physics professor was required by the administration to "integrate faith and learning" in the classroom. So we spent the better part of one lecture attempting this, which he initiated by asking us how our faith was related to the practice of science. After our fumbling attempts to say it meant being cheerful and truthful, he related this anecdote. A colleague had told him that he should never pray for his experiments. "Why?" he asked. "Because if prayer works, then it is miraculous, and no one will be able to duplicate your experiment, which violates the definition of science. But if prayer doesn't work, then it is a waste of time."

Carl Sagan's introduction to the book A Brief History of Time by Stephen Hawking, says it this way, The more virulent form of naturalism says that science has made religion superfluous, and now religion is an impediment to science. Various people have played the attack dog of materialism over the years, Bertrand Russell filled that role in the first half of the 20th century, but in the latter half, none have done so well as Richard Dawkins, a British biologist. In describing his anti-faith in materialism, his complete denial of purpose, he writes: Thus for Dawkins a belief in purpose, and a purposeful God, is not just an eccentric delusion to be humored, but a deceitful lie that prevents science from progressing. In his words to the Edinburgh International Science Festival: "Faith is the great cop-out, the great excuse to evade the need to think and evaluate evidence. Faith is belief in spite of, even perhaps because of, the lack of evidence." In more inflammatory language, "Faith is a kind of mental illness", "one of the world's great evils, comparable to the smallpox virus but harder to eradicate."

One can group all these diverse people together as united in a commitment to a metaphysics of scientific materialism. In addition, they also show the same paradoxical behaviors: a surprising lack of humility discussing what they have never understood, an immovable belief in the progress of man and science, a tragic romanticism finding meaning in a meaningless world, an unflagging goal to deny all purpose, and a religious zeal to fight theistic religion. These "hard science" practitioners disparage religion, but they make no attempt to explain the attractiveness of religion. That task has been left, for the most part, to psychologists and sociologists. Hence the 8th chapter of SRI involves a number of influential "soft science" practitioners: L. Fuerbach (1804-1872), William James (1842-1910), and Sigmund Freud (1856-1939), and their reinterpretation of religion.

A physicist might reply to a statement of faith by questioning the validity of the data, but it is the psychologist who has perfected the ad hominem retort (spoken with feigned surprise) "Why? Is it important to you?" To paraphrase the well-known method, if you can't answer the question, find a question you can answer. So William James, rather than answering the question of God's existence, instead answered the question of the experience of God's existence. Science could not (or would not) make God a proper subject of study, but by refocussing on the human experience of God, science found a proper subject. Which is not to say that the study of man, anthropology, has been very enlightening about the study of God, theology. Can one understand physics by dissecting Einstein's brain? But this is exactly the approach that grew out of the German liberalism of the 1800's. Fuerbach saw religion as a projection of human longings. Freud built on this foundation a rather complex and involved myth about wish-fulfillment and repressed sexual feelings. His view that religion evolved historically from a group of sons that murdered their father to have access to his wives with religious ritual arising from this collective guilt may not be taken too seriously today, but the attitude or approach of deconstructing transcendent truths with materialistic reductionism took firm root in science.

Thus the conflict between science and religion deepened throughout most of the 20th century, with each side saying unflattering (and probably untruthful) statements about the other. As we came to the end of the century, there appeared to be some small indications that the two sides might be reconciled. Paul Davies writes in God and the New Physics that "science may provide a surer path to God". Surer than what? It appears he means that hard science reveals God more clearly than the soft sciences, that physics is better than anthropology in uncovering purpose. William Paley would have agreed. Davies is coy, but he hints that the anthropic principle and the origins of life may indicate teleology, a vital force. What he is referring to is the one anomaly of the 20th century debate, the one semi-respectable attempt to combine religion and science known as Process Philosophy or Process Theology.

Process in Philosophy and Theology

Although neither Process Theology nor Process Philosophy made much of an impact on me either in seminary or graduate school in physics, it evidently was quite compelling to both scientists and theologians slightly older than myself. Somewhere in the 1960's it must have peaked in popularity for quite a number of physicists-turned-philosopher have embraced it, including Barbour, Polkinghorne and perhaps Davies. So despite my indifference, I feel compelled to address its advantages and shortcomings, and perhaps the cause of its fall from fame.

Whitehead, Bergson

There are a number of philosophical and theological problems that previous generations bequeathed us, and none felt the weight of inheritance more burdensome than the generation of the 60's. Orthodox Christianity was saddled with the problem of evil--how a good, all-knowing and all-powerful God could tolerate evil (much less the squares who were all over 30.) Logical positivism seemed completely unable to cope with the explosion of physical theories that were changing our world, and was bogged down, for example, defining "space". Neo-Kantian idealists seemed off in their own little world that was denying the reality of the atom while atom bombs seemed all too real to the rest of the world. Nor did the Laplacian determinists have any answer at all for the causes of war and the promotion of peace. Clearly the times they were a'changing, and all the stodgy philosophies weren't. An approach that captures that mood, that fluidity was surely to be preferred.

Abandonning the primacy of physics and adopting the language of biology, they felt that a proper metaphor might perhaps hold that the world and life were organic, growing and changing while ever staying the same. The danger in this metaphor, of course, is a potential descent into alchemy, the occult and the deification of nature. So there had to be an upfront separation between a respectable philosophy and pagan nature worship, a clear difference between panentheism and pantheism. As Bergson, Whitehead and Tielhard de Chardin tried to express it, God is in everything but everything is not God. God finds himself swept along by history and time just as we do, yet he maintains his identity, like us, despite the changes. And just as time and change influence but do not force us, so God influences us without forcing us to bend to his will.

Perhaps an example will clarify the difference. In Laplacian determinism, the future is contained in the past and is unavoidable, determined. There is no room for improvement over the past unless one hides it in the positions of the atoms like some clever card trick. Likewise in a fatalistic Christianity, God lives outside of time and knows and preordains the future of the world. But for Bergson there is an elan vital that pushes the world toward improvement, toward perfection without actually demanding it. It is a creative force that influences evolution and man to progress without being obvious in either space or time. In Darwin's terminology, natural selection uses random, purposeless, chance events to accomplish a purposeful evolution toward perfection. Given that Bergson and Whitehead developed their views in the decades before WWI, when world trade had reached levels not surpassed until 1980 and many churches had announced the imminent arrival of the millenium as the 1000 years of peace and prosperity promised in the book of Revelation, it is not too surprising to find such optimism. It is perhaps worth noting that Bergson's prolific output diminished abruptly in 1914 at the onset of WWI, publishing exactly one book between 1914 and his death in 1941 which concerned his conversion from Judaism to Catholic Christianity. Irrational exuberance was no match for the brutality of war.

As Europe recovered from the World Wars, optimism had to rise afresh in America, and Whitehead's appointment at Harvard in 1924 ushered in the development of what became known as "Process Philosophy", with a religious component called "Process Theology". An extended quote from the Stanford Encyclopedia of Philosophy has this to say: So if I can summarize, Whitehead opposed the determinism, the secularization of science that had become the goal of logical positivism. He did not see any hope of resurrecting Paley's deism, so he embraced evolutionary change as the expression of how God interacted with the world. This was particularly welcome to those in the religious ghetto of Kant, who welcomed an academic alternative to irrelevance, but was despised by the majority of secularized philosophers who had long since abandonned teleology.

If it was Einstein who had inspired the Neo-Kantian logical positivists, it was Darwin and Bohr that inspired the process philosophers. For Evolution requires, almost as an article of faith, that process be progressive, inspiring a unvocalized hope in improvement of man. Quantum Mechanics argues for the mysterious nature of atoms that do not exist as particles between measurements, but are weirdly distributed waves. The act of measurement, of becoming real, is more significant than the time between, of being real. Clearly this is Whitehead at his best, and many physicists found inspiration in this expression of the new physics.

Not only did process theology find a way to explain evolution, quantum mechanics and keep God in his creation, Whitehead also solves the problem of evil. For God, though omniscient and omnibenevolent, is not omnipotent, but is ravaged by time as we are. Like Rabbi Kushner's God, Whitehead's God inspires our pity, though perhaps not our reverence.

Thus we can see at once both the persuasion and pitfalls of process thought. It strikes a delicate balance between materialistic fatalism and religious teleology, allowing a little bit of both in unspecified proportions. But it risks the condescension of secular science and the irrelevance of a finite deity. It puts enormous faith in the paradigm of Evolutionary progress, a paradigm under attack today from both right and left. At best, it is a resting place in history for travelers between the coasts of fundamentalism and liberalism, between purpose and futility, between the bang and the whimper of life. At worst, it is a opiate for those who never quite understood that God is Dead, and could never be revived in infinite time. Davies captures the mood quite well when he concludes the The Fifth Miracle with:
Last modified, February 12, 2003, RbS