The Definitional Fortress: Atheism in Theory and in Practice
Atheism may be a lack of belief by definition, but in practice it often functions as a worldview. This essay examines the “Definitional Fortress” and the beliefs atheists deny having.
Atheism has a public relations trick so polished it deserves its own exhibit at the Museum of Rhetorical Evasion. When atheists are pressed on the content of their views—when patterns, assumptions, and shared commitments are pointed out—the response is swift and rehearsed: atheism is not a belief system; it is merely a lack of belief. The drawbridge goes up, the portcullis slams shut, and criticism is left shouting into the moat.
Once the danger passes, the gates reopen. Out march confident declarations about reality, knowledge, science, superstition, evidence, and the unreliability of human experience—pronouncements delivered with all the certainty of creed, but none of the accountability. This maneuver is not clever. It is disingenuous.
This rhetorical maneuver deserves a name. I will call it the Definitional Fortress: the habit of retreating to a minimal definition in order to deflect criticism of the broader beliefs, assumptions, or epistemic commitments someone routinely expresses. The fortress is raised when challenged and quietly abandoned once the challenge passes.
The problem is not with the definition of atheism. By definition, atheism addresses exactly one proposition: the existence of gods. Nothing more. Nothing less. Strip it down to its skeleton, and that is all that remains. The problem arises when atheists pretend that this narrow definition exhausts atheism as it exists in the real world. It does not. And pretending otherwise is a refusal to engage honestly with one’s own intellectual commitments.
There is a crucial distinction that must be made: atheism by definition versus atheism as a lived epistemic posture. The first is austere, minimalist, and philosophically tidy. The second is a sprawling network of assumptions, preferences, and methodological commitments that—while not logically required by atheism—are strongly suggested by it and overwhelmingly adopted by those who wear the label.
Supplemental Material
- Appendix I: Anticipated Objections and Clarifications
- Appendix II: Empirical Research on Spiritual Experience
Consider science. There is nothing in atheism that demands acceptance of evolution, the Big Bang, or abiogenesis. An atheist could, in principle, reject all of them. Yet in practice, atheists overwhelmingly affirm these theories. This is not accidental. When supernatural explanations are removed from the table, naturalistic explanations are not merely preferred; they are the only ones left standing. Science, with its methodological naturalism and evidentiary rigor, becomes the best available tool for explaining reality. Atheists tend to trust science not because atheism commands it, but because atheism strongly nudges them there.
This is where the evasiveness begins. These commitments are regularly expressed, defended, and weaponized in debate—until someone labels them what they are: beliefs. At that moment, the definitional fortress is invoked. Not atheism, comes the reply. Just rationality. But rationality is not content-free. It is a framework. And frameworks have content.
One of the most striking consequences of this framework is a pronounced bias against subjective experience as evidence. To be clear, this bias is not entirely unjustified. Subjective evidence is inferior to objective evidence when the goal is establishing external facts about reality. Human perception is fallible, memory is reconstructive, and interpretation is notoriously unreliable. These are well-established facts.
But acknowledging limitations is not the same as wholesale dismissal. And here many atheists cross from skepticism into dogmatism.
Spiritual experiences—visions, altered states, feelings of transcendence, unity, or presence—are routinely dismissed by atheists as lies, delusions, or fantasies. The conversation often ends there, with a smug wave of the hand and the word make-believe. This is epistemic malpractice.
Ironically, the very science atheists appeal to in order to dismiss these experiences confirms that they are real experiences. Neuroscience, psychology, and cognitive science have repeatedly demonstrated that people who report spiritual or religious experiences are undergoing measurable, empirically verifiable mental states. These experiences correlate with distinct neurochemical and neurological patterns, often overlapping with those observed in meditation, flow states, or intense emotional focus (Newberg and d’Aquili; McNamara).
What science does not do is validate the supernatural interpretations often attached to these experiences. That distinction matters. An experience can be real while its explanation is wrong. Conflating the two is precisely the sort of sloppy thinking atheists pride themselves on avoiding—yet frequently indulge in when the topic is religion.
To shut the door entirely on spiritual experience is to discard an enormous body of data with a single gesture. Millions of people across cultures, eras, and belief systems report strikingly similar phenomenological experiences. These reports are not evidence of gods—but they are evidence of something worth studying. Declaring them irrelevant because they are inconvenient is not skepticism. It is bias.
And bias dressed up as rigor is still bias.
Objectivity is a core precept of critical thinking. It demands that evidence be evaluated on its merits, not dismissed because it makes us uncomfortable or because we dislike the conclusions others draw from it. Memorizing logical fallacies does not make one a critical thinker any more than owning a lab coat makes one a scientist. Critical thinking requires intellectual humility, curiosity, and a willingness to interrogate one’s own assumptions.
The retreat into the definitional fortress allows atheists to avoid that interrogation. It creates a one-way mirror: atheists scrutinize everyone else’s beliefs while insisting that their own worldview is merely an absence, a blank slate, a neutral default. It is not. It is a worldview with contours, tendencies, and biases—some defensible, others overdue for critique.
Calling this out is not an attack on atheism. It is a demand for honesty. If atheists wish to claim the mantle of reason, they must apply it inward as rigorously as they apply it outward. Otherwise, they are not defending rationality. They are protecting an identity.
And that, ironically, looks a lot like faith.
If you find this work valuable and want to support future research and writing, including research and web-hosting costs, you can do so on patreon.
Appendix I: Anticipated Objections and Clarifications
Objection I: “These Aren’t Atheist Beliefs—They’re Just Rational Ones”
This objection relies on a sleight of hand. The ideas under discussion—confidence in science, rejection of supernatural explanations, preference for methodological naturalism—are routinely expressed as part of atheist argumentation. They appear in atheist forums, in debates with theists, and in critiques of religion, offered explicitly from the standpoint of atheism.
This is not a neutral coincidence. When individuals consistently advance certain ideas while speaking as atheists, they are tacitly presenting those ideas as components of their atheist worldview. One does not repeatedly argue from a position in explicitly atheist contexts and then plausibly deny any connection between the argument and the identity under which it is made.
Appeals to “just rationality” do not resolve this problem. Rationality is not a content-free state. A sustained devotion to critical thinking principles entails substantive epistemic positions: commitments regarding what counts as evidence, which explanatory frameworks are legitimate, and which sources of knowledge are presumptively unreliable. These positions form a structured worldview. To deny that such a framework constitutes a belief system is not modesty; it is misrepresentation.
Objection II: “You’re Redefining Atheism”
I am not redefining atheism. Atheism, by definition, is the lack of belief in gods. That definition remains intact and unchallenged. What is under examination here is atheism as it functions in practice.
In the real world, atheism is rarely expressed in isolation. It is typically accompanied by a clear attachment to certain ideas: trust in science, skepticism toward the supernatural, and confidence in naturalistic explanations. These ideas are not logically entailed by atheism, but they are overwhelmingly adopted by those who identify with the label—and they are advanced in the course of atheist discourse itself.
To insist that atheism can be entirely devoid of these beliefs while simultaneously deploying them under the banner of atheism is to hide behind definition while acting beyond it. This is a textbook example of the Definitional Fortress.
Objection III: “Acknowledging Spiritual Experience Opens the Door to Superstition”
This objection confuses inquiry with endorsement. Critical skepticism is grounded in radical doubt: conclusions are withheld until evidence is examined. To categorically dismiss spiritual experiences without investigation is not skepticism—it is a conclusion reached in advance of evaluation.
Contemporary neuroscience and psychology already demonstrate that many reported spiritual experiences correspond to identifiable, measurable mental states. The experiences themselves are real, even if the explanations commonly offered for them are mistaken. A critical skeptic does not refuse to examine a phenomenon because others have misinterpreted it. They study it precisely because it has been misunderstood.
When atheists shut the door on spiritual experience entirely, they are not suspending judgment—they are exercising it. In doing so, they step outside the critical-skeptical mindset and replace inquiry with dismissal. That is not rigor. It is avoidance.
Objection IV: “Subjective Experience Is Worthless as Evidence”
Subjective experience is not worthless; it is limited. Science has repeatedly shown that at least some subjective experiences reported by believers correspond to real, reproducible phenomena. In this sense, subjective reports can function as reliable indicators that something is occurring.
A useful analogy is digging for clams. Bubbles in the sand are not the clam itself, nor do they explain how it functions, but they reliably indicate that something substantial lies beneath the surface. Subjective experience operates in the same way. It flags phenomena that warrant further investigation.
Where subjective experience reliably fails is in identifying the cause or mechanism of the experience. That explanatory work requires objective, empirical methods. But dismissing subjective experience outright eliminates the very markers that tell us what needs to be studied. Subjective evidence is therefore not the endpoint of inquiry—it is often the starting point.
Many atheists nevertheless discard it wholesale. In doing so, they abandon potential data in favor of epistemic convenience. That is not skepticism. It is certainty masquerading as restraint.
Objection V: “This Is Just Tone Policing Atheists”
This critique is misplaced. The issue here is not tone but standards. Atheists routinely demand that religious believers subject their assumptions to rigorous scrutiny, expose hidden commitments, and justify their claims according to consistent evidentiary rules.
Those standards do not vanish when applied inward.
Appealing to reason while shielding one’s own intellectual attachments from examination—by insisting they are “just rational” or “not really beliefs”—is an act of identity protection, not critical thinking. Skepticism without self-skepticism is not a virtue. It is ideology with better branding.
Appendix II: Empirical Research on Spiritual Experience
Although spiritual experience is not the crux of this post, it was referenced and it is easy to see that many will want to challenge some of the claims made, even if they were claims made to support a different point altogether.
This appendix does not argue that spiritual experiences confirm supernatural causes. It documents something simpler and more defensible: many reported “spiritual” states have identifiable, measurable correlates in the brain and body, which makes them legitimate targets for empirical study.
A. Meditation and Regional Cerebral Blood Flow
A preliminary SPECT study measured regional cerebral blood flow changes in experienced Tibetan Buddhist meditators, comparing baseline to a meditative state after tracer injection. The paper reports state-related blood-flow differences during meditation relative to baseline.
Online access:
https://pubmed.ncbi.nlm.nih.gov/11306250/
MLA citation:
Newberg, Andrew, et al. The Measurement of Regional Cerebral Blood Flow during the Complex Cognitive Task of Meditation: A Preliminary SPECT Study. Psychiatry Research: Neuroimaging, vol. 106, no. 2, 2001, pp. 113–122.
B. Personal Prayer and Social-Cognition Networks
An fMRI study comparing different forms of prayer found that improvised personal prayer was associated with activation in regions implicated in social cognition and mentalizing.
Online access:
https://pubmed.ncbi.nlm.nih.gov/19246473/
Publisher page:
https://academic.oup.com/scan/article/4/2/199/1625805
MLA citation:
Schjoedt, Uffe, et al. Highly Religious Participants Recruit Areas of Social Cognition in Personal Prayer. Social Cognitive and Affective Neuroscience, vol. 4, no. 2, 2009, pp. 199–207.
C. Mystical Experience Recall and Distributed Neural Correlates
An fMRI study of Carmelite nuns measured neural activity during subjectively reported mystical states.
Online access:
https://pubmed.ncbi.nlm.nih.gov/16872743/
Publisher page:
https://www.sciencedirect.com/science/article/abs/pii/S0304394006006392
MLA citation:
Beauregard, Mario, and Vincent Paquette. Neural Correlates of a Mystical Experience in Carmelite Nuns. Neuroscience Letters, vol. 405, no. 3, 2006, pp. 186–190.
D. Glossolalia and Altered Control/Self-Monitoring Patterns
A SPECT study examined regional cerebral blood flow during glossolalia.
Online access:
https://pubmed.ncbi.nlm.nih.gov/17046214/
MLA citation:
Newberg, Andrew B., et al. The Measurement of Regional Cerebral Blood Flow during Glossolalia: A Preliminary SPECT Study. Psychiatry Research: Neuroimaging, vol. 148, no. 1, 2006, pp. 67–71.
E. Temporal-Lobe Hypothesis as Neuropsychological Framing
A general hypothesis proposing links between mystical experience and temporal-lobe activity.
Online access:
https://pubmed.ncbi.nlm.nih.gov/6664802/
Open PDF:
https://www.demenzemedicinagenerale.net/pdf/Religious_and_mystical_experiences_Persinger.pdf
MLA citation:
Persinger, Michael A. Religious and Mystical Experiences as Artifacts of Temporal Lobe Function: A General Hypothesis. Perceptual and Motor Skills, vol. 57, no. 3, 1983, pp. 1255–1262.