Methodological Naturalism

in Our Search for Truth:
A Brief Introduction

by Craig Rusbult, Ph.D.

      Open and Closed — What is the difference?
      Currently, science is typically closed by methodological naturalism, a proposal to require that scientists must include only natural causes in their scientific theories.  The difference between science that is open and closed is the difference in responding to a question:  Has the history of the universe included both natural and non-natural causes?  In an open science (liberated from rigid methodological naturalism) this question can be evaluated based on scientific evidence;  a scientist begins with methodological naturalism, but is flexible (not rigid) and is willing to be persuaded by evidence and logic.  In a closed science (restricted by rigid methodological naturalism), evidence and logic are not the determining factors because the inevitable conclusion — no matter what is being studied, or what is the evidence — must be that "it happened by natural process."

      I think methodological naturalism is theologically acceptable for a Christian so the main questions in this page are about our definitions of science, logic, and utility, by asking (about methodological naturalism) "Is it scientific?  Is it logical?  Is it useful?  Is it a rule?"

      Is it scientific?
      A principle of methodological naturalism cannot be logically derived from science (so it is non-scientific) but is compatible with science (so it is not un-scientific).
      But if we define science as "whatever scientists do," and most scientists currently use methodological naturalism, doesn't this make it scientific?  Maybe.  It depends on whether we define science as an activity with goals or a game with rules.

      Is it scientifically logical?
      Let's compare the process of methodological naturalism and the process of science.  With methodological naturalism (MN), circular logic converts a naturalistic assumption (that everything which does occur in nature is natural) into a naturalistic conclusion (that everything which has occurred in nature has been natural).  But circular logic is bad logic;  it is trivial and misleading.  The circular MN-process automatically converts an assumption into a conclusion that is inevitable, that cannot be changed by a logical evaluation of observable evidence.  But evidence and logic are the foundations of science-process.  Since the circular MN-process does not depend on evidence and logic, it does not depend on science-process, but the conclusion demanded by methodological naturalism — that "it happened by natural process" — is considered to be scientific.  Do you think this is rational?  It does seem strange, but the overall result is that methodological naturalism provides a way to bypass the process of science and then claim the authority of science as support.

      Is it scientifically useful?
      In science — in a logical search for truth about nature — is methodological naturalism a useful approach?  Although we can't be certain, probably methodological naturalism will be useful if its assumptions are true, if there is a match between "what methodological naturalism assumes about the world" and "how the world really is."  IF the history of the universe really has included only natural process, then methodological naturalism is correctly assuming an all-natural history, and methodological naturalism will be useful because it helps scientists avoid being distracted by false theories about non-natural events.  But IF non-natural events really did occur during history, the premise of methodological naturalism is false, and it will be harmful when it inevitably forces scientists to reach some false conclusions.
      Imagine that we're beginning our search for truth with an appropriately humble attitude by refusing to assume that we already know — with certainty, beyond any doubt — what kind of world we live in.  If we don't know whether naturalism "matches the reality," what is our best scientific strategy for finding truth?  The best strategy is an open science, with scientists humbly asking a question instead of arrogantly assuming an answer.  While we're in a questioning state of mind, exploring various aspects of nature, an open science (not constrained by methodological naturalism, not demanding an all-natural history) will let scientists use evidence-and-logic to reach a conclusion.  In open science, a scientist begins with methodological naturalism by assuming that (consistent with MN) there is a natural explanation, thereby adopting a heuristic-MN.  But an open-thinking scientist rejects rigid-MN by choosing the freedom to use both MN and non-MN modes of thinking while logically evaluating the evidence, to consider a wider range of possibilities that include both non-design (which is consistent with methodological naturalism) and design (which may or may not be consistent with methodological naturalism).  In open science, a scientist begins with an MN-assumption but does not insist that — no matter what the evidence indicates — it is necessary to end with an MN-conclusion.
      Perhaps the search by Closed Science is occasionally futile, like trying to explain how the faces on Mt. Rushmore were produced by undirected natural process (erosion,...) even though, when scientists are restricted in this way, the finest creativity and logic will fail to find the true origin.  Perhaps methodological naturalism is putting scientists in the position of a man who is diligently searching for missing keys in the kitchen when the keys are sitting on a chair on the front porch.  No matter how hard he searches the kitchen, he won't find the keys because they aren't there!  On the other hand, if the keys really are in the kitchen, probably they will be found by someone who believes "the keys are in the kitchen" and is diligently searching there, not by a skeptic.  Proponents of Open Science are not saying "don't search in the kitchen";  instead, they are saying "search everywhere, including the kitchen and porch," and this flexibility should make Open Science more effective.

      Is it a rule of science?
      Is science a game with rules?  This is an interesting sociological perspective, useful for thinking about interpersonal dynamics and institutional structures.  For example, it explains how those with power to make decisions (about publishing, funding, and hiring in the community of scientists) can decide that a rigid methodological naturalism should be a "rule of science" that is unwritten yet is enforced.  Yes, this can be done, but is it wise?
      Let's compare "cheating" in sports, business, and science.  In a Strong Man Contest, if other contestants carry a refrigerator on their backs, one man should not be allowed to move it with a two-wheel cart because this is not useful for achieving the goal of the game, for deciding who is the strongest man.  But if the goal of a business is to deliver refrigerators quickly, many times throughout the day, a two-wheeler is useful.
      Instead of a game with rules, it seems better to define science as an activity with goals.  For most scientists the main goal of science (although it isn't the only goal) is finding truth about nature.  But if we demand that the answer to every question about the history of nature must be that "it happened by natural process," we might force scientists to reach some unavoidable false conclusions.  When some scientists recognize this and they question the usefulness of rigid methodological naturalism, is it cheating or wisdom?

      Natural or Logical?
      In scientific thinking, in science research and science education, is rigid methodological naturalism always wise?  When we ask this question, we're actually asking, "Should science be a search for natural explanations or logical explanations?"  What do you think?  While we're investigating the history of the universe, if we find a conflict between naturalism and logic, should we give a higher priority to naturalism or logic?



Circular Logic hidden by Verbal Ambiguity
In natural science, do we have to explain natural phenomena and natural history by natural causes?  No, this claim is just circular logic that's camouflaged with verbal ambiguity by using natural to mean both "pertaining to nature" (three times) and "normal appearing" (once).

Methodological Naturalism and Intelligent Design

A page about "Intelligent Design in Science?" includes Naturalism (methodological & philosophical) and Intelligent Design which looks at these questions:  In our search for truth about the history of nature, what are the advantages and disadvantages of non-flexible methodological naturalism (MN)?  How can MN be useful and non-useful, scientifically and in other ways?  Is MN acceptable, scientifically and theologically, for Christians?  What are the similarities and differences between methodological naturalism and atheistic philosophical NATURALISM?  What are the relationships between them, and is there a tendency for either to cause the other?

Here are some problems of Closed Science:

      Two Limits for Science
      What are the limits for what can claim to be science?  One proposal is methodological naturalism (MN), which requires that scientific theories can postulate only natural causes.
      What are the limits for what MN-Science can claim to explain?  If we decide to accept methodological naturalism, a second limit is logically necessary:  If an event really does involve a non-natural cause, any explanation of the event by MN-Science (in terms of only natural causes) will be incomplete or incorrect.  This limit, regarding the potential for unavoidable error in MN-Science, is MN-Humility.

      A Change of Mind
      In 1998, I was willing to support either of two options: accepting methodological naturalism (and acknowledging MN-Humility), or rejecting methodological naturalism.  Summarizing the rationality of MN-plus-Humility, I said: "We can view a restricted MN-science as one aspect of a broader ‘search for truth’ that considers all possibilities without imposing metaphysically biased restrictions on theorizing.  In this open search for truth,... MN-science can be a valuable resource that should be respected as an expert witness, but it should not be the judge and jury when we're defining reality and rationality."
      Two years later, when I began revising my overviews of Origins Questions, I concluded that — although both options are theologically acceptable for a Christian — it seems more rational to reject a rigid methodological naturalism, mainly because I had become convinced that open science is better science, but also because of the rarity and futility of humility.

      The Futility of Humility
      In principle, the combination of "MN-Science plus MN-Humility" is logically acceptable.  In practice, the result is not satisfactory because even when MN-Humility is acknowledged (which is rare) it is not effective.  Why?
      Think about what happens when a "non-scientific" design theory and a "scientific" non-design theory both claim to describe the same event, such as the origin of life.  Due to the cultural authority of science, the nonscientific theory is not respected because most people assume that, for a theory about nature, "not scientific" means "probably not true."  Instead, the scientific theory is assumed to be more plausible, even if the scientific evidence does not support it, because (as explained above) methodological naturalism provides a way to bypass the process of science and then claim the authority of science as support.  And in a classroom where "only science is taught," only the naturalistic non-design theory is taught, and it is taught as "the conclusion of science."

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Here are other related pages:

my FAQ about Creation, Evolution, and Intelligent Design
summarizes many ideas about Methodological Naturalism
( can a Christian use MN?  is MN scientifically useful? )
in Sections 7C-7D and (in 1A-7B) covers much more

my detailed overview of
Methodological Naturalism

a fascinating page by Paul Nelson about
Methodological Naturalism and the Rules of Baseball & Cricket

pages by other authors about

This page is

Copyright © 2003 by Craig Rusbult, all rights reserved