The term "the ontological-epistemological identity fallacy" has been suggested to me in private correspondence as a name for this fallacy. However, that term receives no hits on google.

An example might be as follows: people are very complicated, and clinical psychology is very complicated. Therefore all simple rules for clinical psychologists must be wrong.

If there is no name for this fallacy, is there a name for a related fallacy?

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    That sounds like a pretty apt name for it based on the definition. Naming fallacies is a common question here on philosophy.se, but it's pretty irrelevant what the name of a fallacy is (except for proper fallacies of formal logic) since for informal fallacies there's a lot of room to argue whether the usage is fallacious.
    – virmaior
    Commented Jun 10, 2015 at 14:23
  • I second Ron Royston, it is unclear what "complex phenomena" and "complex explanation" mean here. I could only find "ontological-epistemological identity principle", which holds that "human existence, in all its regional and epochal forms, follows entities, in all their regional and epochal forms, in a play of connaturality." religiousstudies.stanford.edu/wp-content/uploads/… Clearly not the intended meaning.
    – Conifold
    Commented Jun 10, 2015 at 23:33
  • An example might be as follows: people are very complicated, and clinical psychology is very complicated. Therefore all simple rules for clinical psychologists must be wrong. Commented Jun 10, 2015 at 23:54
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    I would say the example you give fits under the category "fallacy of division" (en.wikipedia.org/wiki/Fallacy_of_division) but I repeat the goal is not to name fallacies but to identify arguments as fallacious with an explanation as to why. Names are merely shorthand for this.
    – virmaior
    Commented Jun 11, 2015 at 0:34
  • Any kind of fallacy is useless because it is just a convention.
    – Masacroso
    Commented Jun 12, 2015 at 0:22

4 Answers 4


Agreeing with virmaior's comment that this falls under "fallacy of division". A possible counterexample is Chess, where simple rules, multiplied with each other, and multiplied over multiple possible future moves, results in great complexity.


We bow to this fallacy when we set out to govern or model a situation and will not give simple solutions a chance. The fact that laws, in general, now come into being as huge agglomerations of overplanning and hyper-regulation rather than starting out simple and developing naturally in response to arising situations as Common Law did for generations, is a result.

We have faith that a complex problem will naturally only be amenable to a complex set of rules. But this is totally an illusion. In fact those rules create conflicts, and focussing on refinement does not establish coverage of the solution space.

I agree that finding a name is not really all that important. But what is the basic impulse behind the fallacy?

To me the essence of this fallacy is the denial of the experience of theoretical parsimony. We know that vast swathes of science can be captured in extremely simple rules. But we ignore this fact in real life. We are fascinated by the complexity that can come out of a simple statement like Mandelbrot's function, well out of proportion with its meaning. We have a deeply embedded mistrust of simplicity, and we look upon effective simplicity as genius or magic of some sort, or alternately as charlatanry or witchcraft.

The idea that effective simplicity is magic seems to be the driving force behind the faith that we cannot have a scientifically literate population -- that physics is hard, but predicting sports scores is somehow comparatively easy, and we should not really expect people to invest half the energy in learning physics as in analysing football, because it won't pay off.

I think that the problem is that if we accept this kind of explosion of possibilities as a natural thing, we must lessen our faith that we can predict the outcome of the simple rules upon which we make other decisions. This would impede our faith in the ability of law to protect us, and for order to be maintained without ambiguity. So this fallacy is tied up intimately with the "Law of Unintended Consequences", and with the patriarchal racket of throwing your burdens onto the shoulders of someone more competent than yourself and somehow feeling safer rather than feeling unsafe because you are obviously less in control of what might happen.

Plying that psychological impulse as if it were an argument is unfair.

In the interest of practicality, let's not seek a name, but a tactic for circumventing it. Naming a fallacy seldom abolishes it, and often simply derails the argument into an argument about whether this argument was, in fact, an instance of said fallacy.

Manufacturing and computer programming have adopted a framework for combatting this impulse in the form of the notion of agility http://agilemanifesto.org/ which derives from leanness http://www.lean.org/WhatsLean/. The position emphasizes that the ability to adapt to change is the paramount power needed for success, as opposed to strength, endurance or outright speed. And that metaphorical agility, like actual agility, is fostered by awareness of one's state, simplicity of the options entertained, and a breadth (rather than a depth) of experience.

To the degree that this perspective can be injected into an argument, and the scientific approach of experimentation with actual solutions can be allowed to function, the argument can be broken down by demonstration. Solving 80% of the problem quickly in a few steps, can establish the idea that the remaining 20% can be solved without an insane investment in complexity.

In a more abstract setting this often proceeds by identifying a single convention that halves the imagined complexity by applying a simple rule. Since it only takes very few divisions in half to reduce something very large to something quite small, this can interrupt the idea that the very large thing has to be attacked with another very large thing.


In general, heuristic technique supports the opposite of your claim (points towards the fallacy you are trying to name). Occam's razor, sometime referred to as the law of parsimony, argues that given multiple explanations, the one which requires the least assumptions is likely closest to the truth. This isn't providing the name of the fallacy, but is the name of a common argument against the fallacious position that complex systems require belabored complex answers.

A great example of this is the pre-heliocentric mapping of the solar systems orbital paths. It was burdened with overly complex, loopty-loop tracks. This is an example of how a complex answer was in fact a symptom of an invalid assumption and an incomplete understanding if the system as a whole.

In your question you refer to the complexity of human psychology. However, I believe that psychology tries to eliminate complexity and focus on the what is believed to be a common set traits and behaviors - standardizing a treatment regiment for specific situations, and less focused on specific individuals and the complexity of each one's life.


This is not directly an answer, but…

There are two terms — “weaker” and “stronger” — as follows.

A stronger claim or position is a more complex one — it postulates more. (As a rule) such have more explanatory power but are more vulnerable to objections. (Conversely, if they survive objections, they have more credibility than a weaker claim.)

A weaker claim or position has fewer implications and less explanatory power; (as a rule) such are less vulnerable to objections, but concomitantly less valuable.

As for the question… I suggest that this is not a fallacy.

If a phenomenon really is complex, then surely it would require commensurate complexity, one way or another, to explain it? The converse would be that there was some (non-commensurately) simple phenomenon that somehow explained something more complex than itself. A (relatively) simple explanation could work if it appealed to other factors without mentioning them, but then it would be indicated to mention those factors.)

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    Welcome to Philosophy.SE! "A stronger claim or position is a more complex one": I don't know if this is true. I can think of many mathematical theorems that make stronger claims by being less complex (fewer assumptions). Commented Jan 14, 2016 at 14:56
  • This is not mathematics. Neither is psychology mathematics. “Stronger” and “weaker” are philosophical jargon. I am not going to die for the accuracy of my definition, but it is at least recognisably an attempt to define or explain two recognised terms. (I submit that these are harder than average to define and explain.)
    – Carsogrin
    Commented Oct 18, 2016 at 16:40

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