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The Boundaries Between Science and Religion: Alan Lightman on Different Kinds of Knowledge

“The physical universe is subject to rational analysis and the methods of science. The spiritual universe is not. All of us have had experiences that are not subject to rational analysis. Besides religion, much of our art and our values and our personal relationships with other people spring from such experiences.”


Alan Lightman, whose beautiful meditation on our yearning for permanence in a universe that offers none, looks at the tension between science and religion in The Accidental Universe: The World You Thought You Knew.

In the essay, “The Spiritual Universe,” Lightman sets out to reconcile his personal struggle between religion and science. In so doing he sets out the necessary criteria for science to be compatible with religion:

The first step in this journey is to state what I will call the central doctrine of science: All properties and events in the physical universe are governed by laws, and those laws are true at every time and place in the universe. Although scientists do not talk explicitly about this doctrine, and my doctoral thesis adviser never mentioned it once to his graduate students, the central doctrine is the invisible oxygen that most scientists breathe. We do not, of course, know all the fundamental laws at the present time. But most scientists believe that a complete set of such laws exists and, in principle, that it is discoverable by human beings, just as nineteenth-century explorers believed in the North Pole although no one had yet reached it.

Our knowledge of scientific laws is provisional. We do not know all the laws but we believe in a complete set of them. We further believe, in principle anyway, that humans will uncover these laws. An example of a scientific law is the conservation of energy.

The total amount of energy in a closed system remains constant. The energy in an isolated container may change form, as when the chemical energy latent in a fresh match changes into the heat and light energy of a burning flame— but, according to the law of the conservation of energy, the total amount of energy does not change.

Even scientific laws that we already know about are updated and refined over time. Lightman offers the replacement of Newton’s law of gravity (1687) by Einstein’s deeper and more accurate law of gravity (1915). These revisions are part of the very fabric of science.

Next, Lightman provides a working definition of God.

I would not pretend to know the nature of God, if God does indeed exist, but for the purposes of this discussion, and in agreement with almost all religions, I think we can safely say that God is understood to be a Being not restricted by the laws that govern matter and energy in the physical universe. In other words, God exists outside matter and energy. In most religions, this Being acts with purpose and will, sometimes violating existing physical law (that is, performing miracles), and has additional qualities such as intelligence, compassion, and omniscience.

Lightman then offers a continium of religious beliefs based on the degree to which God acts in the world. At one end is atheism — or denying the existence of god. Moving along the spectrum, we find deism, which was a prominent view in the seventeenth and eighteenth centuries that God created the universe but has not acted since this spark.

Voltaire was a deist. As God’s role expands we find immanentism, which holds that God created the universe and its scientific laws. Under this view, God continues to act through the repeated application of those laws. We can probably put Einstein in the immanentism camp. (Philosophically both deism and immanentism are similar because God does not perform miracles.)

Opposite atheism lies interventionism. Most religions, including Christianity, Judaism, Islam, and Hinduism subscribe to this view, which is that God created the universe and its laws and occasionally violates the laws to create unpredictable results.

Lightman argues that all of these views, except interventionism, agree with science.

Starting with these axioms, we can say that science and God are compatible as long as the latter is content to stand on the sidelines once the universe has begun. A God that intervenes after the cosmic pendulum has been set into motion, violating the physical laws, would clearly upend the central doctrine of science.

Lightman cites Francis Collins, who offers some thoughtful advice on reconciling a belief in an interventionist God and science, or at least, deciding which to turn to for answers to the right kinds of questions. They are often very different.

“I’ve not had a problem reconciling science and faith since I became a believer at age 27 … if you limit yourself to the kinds of questions that science can ask, you’re leaving out some other things that I think are also pretty important, like why are we here and what’s the meaning of life and is there a God? Those are not scientific questions.

Under this reconciliation, miracles cannot be analyzed by the methods of science. This is an echo of Richard Feynman, who put it most clearly in one of his letters, saying that science only tells us if we do something then what will happen? Cause and effect. It doesn’t give us any guidance on the question of should we do it?

Lightman, himself, falls in the atheist camp.

I am an atheist myself. I completely endorse the central doctrine of science. And I do not believe in the existence of a Being who lives beyond matter and energy, even if that Being refrains from entering the fray of the physical world. However, I certainly agree with (Other Scientists) that science is not the only avenue for arriving at knowledge, that there are interesting and vital questions beyond the reach of test tubes and equations. Obviously, vast territories of the arts concern inner experiences that cannot be analyzed by science. The humanities, such as history and philosophy, raise questions that do not have definite or unanimously accepted answers.

And yet we must believe in things we cannot (yet) prove. Lightman himself believes in the central doctrine which cannot be proven. At most we can only say there is no evidence to contradict it. This is what Karl Popper called real science – a process by which we hypothesize and then attack our hypotheses. A scientific “fact” is one that has stood up to extraordinary scrutiny.

With much of life, and much meaning in the world, there are often things outside of the scientific realm. These are worth considering.

I believe there are things we take on faith, without physical proof and even sometimes without any methodology for proof. We cannot clearly show why the ending of a particular novel haunts us. We cannot prove under what conditions we would sacrifice our own life in order to save the life of our child. We cannot prove whether it is right or wrong to steal in order to feed our family, or even agree on a definition of “right” and “wrong.” We cannot prove the meaning of our life, or whether life has any meaning at all. For these questions, we can gather evidence and debate, but in the end we cannot arrive at any system of analysis akin to the way in which a physicist decides how many seconds it will take a one-foot-long pendulum to make a complete swing. The previous questions are questions of aesthetics, morality, philosophy. These are questions for the arts and the humanities. These are also questions aligned with some of the intangible concerns of traditional religion.

Lightman recalls his time as a grad student in physics and the concept of a “well-posed problem” — a question with “enough clarity and precision that it is guaranteed an answer.” Put another way, scientists are trained not to “waste time on questions that do not have clear and definite answers.” And yet questions without clear and definite answers are sometimes just as important. Just because we can’t apply the scientific method to them doesn’t mean we shouldn’t consider them.

[A]rtists and humanists often don’t care what the answer is because definite answers don’t exist to all interesting and important questions. Ideas in a novel or emotion in a symphony are complicated with the intrinsic ambiguity of human nature. That is why we can never fully understand why the highly sensitive Raskolnikov brutally murdered the old pawnbroker in Crime and Punishment, whether Plato’s ideal form of government could ever be realized in human society, whether we would be happier if we lived to be a thousand years old. For many artists and humanists, the question is more important than the answer.

The question is more important than the answer — just as the journey is more important than the destination and the process is more important than outcome.

As the German Poet Rainer Maria Rilke put it a century ago:  “We should try to love the questions themselves, like locked rooms and like books that are written in a very foreign tongue.”

“As human beings,” Lightman argues, “don’t we need questions without answers as well as questions with answers?”

The God Delusion, a widely read book by Richard Dawkins, uses modern tools to attack two common arguments for the existence of God: Intelligent Design (only an intelligent and powerful being could have designed the universe) and that only the action and will of God explains our morality and desire to help others. Dawkins convincingly shows that Earth could have arisen from the laws of nature and random processes, without the intervention of a supernatural and intelligent Designer. Our sense of morality and altruism could be a logical derivative of natural selection.

However, as Lightman reminds us, refuting or falsifying the arguments put forward to support a proposition does not necessarily falsify the proposition itself.

Science can never know what created our universe. Even if tomorrow we observed another universe spawned from our universe, as could hypothetically happen in certain theories of cosmology, we could not know what created our universe. And as long as God does not intervene in the contemporary universe in such a way as to violate physical laws, science has no way of knowing whether God exists or not. The belief or disbelief in such a Being is therefore a matter of faith.

Lightman is troubled by Dawkins’ wholesale dismissal of religion.

Faith, in its broadest sense, is about far more than belief in the existence of God or the disregard of scientific evidence. Faith is the willingness to give ourselves over, at times, to things we do not fully understand. Faith is the belief in things larger than ourselves. Faith is the ability to honor stillness at some moments and at others to ride the passion and exuberance that is the artistic impulse, the flight of the imagination, the full engagement with this strange and shimmering world.

Indeed, William & Ariel Durant have argued that we need religion; it is part of our fabric of understanding and living in the world.


With that, Lightman brings the essay to a beautiful conclusion.

The physical and spiritual universes each have their own domains and their own limitations. The question of the age of planet Earth, for example, falls squarely in the domain of science, since there are reliable tests we can perform, such as using the rate of disintegration of radioactive rocks, to determine a definitive answer. Such questions as “What is the nature of love?” or “Is it moral to kill another person in time of war?” or “Does God exist?” lie outside the bounds of science but fall well within the realm of religion. I am impatient with people who, like Richard Dawkins, try to disprove the existence of God with scientific arguments. Science can never prove or disprove the existence of God, because God, as understood by most religions, is not subject to rational analysis. I am equally impatient with people who make statements about the physical universe that violate physical evidence and the known laws of nature. Within the domain of the physical universe, science cannot hold sway on some days but not on others. Knowingly or not, we all depend on the consistent operation of the laws of nature in the physical universe day after day— for example, when we board an airplane, allow ourselves to be lofted thousands of feet in the air, and hope to land safely at the other end. Or when we stand in line to receive a vaccination against the next season’s influenza.

Some people believe that there is no distinction between the spiritual and physical universes, no distinction between the inner and the outer, between the subjective and the objective, between the miraculous and the rational. I need such distinctions to make sense of my spiritual and scientific lives. For me, there is room for both a spiritual universe and a physical universe, just as there is room for both religion and science. Each universe has its own power. Each has its own beauty, and mystery. A Presbyterian minister recently said to me that science and religion share a sense of wonder. I agree.

The Accidental Universe is a mind-bending read on the known and unknowable, offering a window into our universe and some of the profound questions of our time.