Rationality Alone Won’t Make You Right (Even Suicide Bombers are Rational)

The quality of rationality is something we intuitively understand – or, at least, we think we do.

It is synonymous with reason – that central driver behind the age of enlightenment, and the means by which we can truly hope to understand the world. Yet reason, or rationality, is one of those concepts that we are so familiar with that we never really bother to explore its essence, and as such, we might fail to grasp what it really entails.

If the title of this article struck you as absurd, and you do not grant that a person capable of blowing themselves up in a murderous act of terror could possibly be rational, then perhaps you should read on.

This article will explore the nature of rationality – its relation to logic, and its application by humans. As we’ll see, human rationality can be both magnificent, and fickle – with equal potential to guide us to the truth of reality, or to funnel us into labyrinths of alluring falsehoods. In order to wield rationality such that we might seek the former, and avoid the latter, it helps to know something about how it works.

As it turns out, there are two additional components with which rationality must be entwined in order to point us in the direction of truth. The first: empirical evidence, is widely lauded as essential, but the second is rather more subtle and less appreciated, yet no less important, as we’ll see.

You’re walking home one Friday evening, as the sun loses its brilliance and begins to shine with a muted orange glow. The air is crisp and bracing, but nonetheless to you feels utterly refreshing; nothing could ruin the beauty of the moment. Work is over for the week, and the following days are filled with the promise of lazy indulgence.

The streets around you pulse with the movements of a thousand similarly liberated pedestrians, each making a beeline for their respective home.

Suddenly, an explosion thunders out in a violent flash nearby, instantly killing a host of these unfortunate souls – including the one who orchestrated the attack.

In the aftermath, the survivors lament the tragedy – decrying the senselessness of the murders. The news media illustrates the troubled mind of the bomber – highlighting his antisocial history, and painting him as a hopelessly irrational agent – minimizing the religious motivations and instead pontificating on the absurd unreason of this, and any such act of terror.

Yet, in fact, nothing irrational has come to pass.

Just as the desires of the commuters to get home from work could be lauded as perfectly reasonable behaviour for working class people on a Friday evening, so too were the bomber’s invidious actions entirely reasonable – as we’ll see in a moment.

But although such harmful religious demonstrations are important case studies for rationality, we won’t mire ourselves in the purely political, and instead approach the discussion from a number of interesting angles.

What it means to be rational

One of the fundamental drivers of human behaviour, is our system of beliefs.

We firmly believe, for example, that our employer will furnish our bank accounts with money if we go to work on Monday morning – so we do.

We believe with absolute conviction that jumping out of our tenth-story office window will kill us – so we don’t.

These behaviors are perfectly rational, because they are consistent with our system of beliefs – they are derived directly from specific beliefs.

If you had been fired from your job, and then strutted in on Monday morning, confident that your boss would pay you, this would be an irrational thing to do – because it directly contradicts what you believe to be true.

Rationality then, is a kind of human extrapolation of formal logic –a rigid system of axioms and rules, like those that give rise to number theory. To illustrate the mechanical, formal nature of logic, take for example a starting axiom (the formal equivalent of a belief) such as:

AXIOM A: If you add 1 to any number, the result will be the successor to that number.

From this, you could derive the number 2 from 1, and then 3 from 2, and 4 from 3, and so on – building up this army of ‘conclusions’ from the base axioms.

In any such formal system of logic, it is of utmost importance that the system is consistent; that is, there are no contradictions.

For instance, if number theory also had an axiom like:

AXIOM B: If you add 1 to any number, the result will not be the successor to that number.

Then you could simultaneously derive 2+1=3, and 2+13

– a blatant contradiction, which undermines the entire structure of the system, and precludes any coherent semblance ‘logic’ from being applied. If this kind of contradiction is found, then it is necessary to check either the validity of your derivation (does AXIOM A really lead to the conclusion that 2+1=3?), or to restructure the axioms such that they are consistent – i.e. remove AXIOM B.

Rationality –  the human application of this kind of formal logic – must adhere to these same principles.

Now, hopefully you can see that rationality alone is insufficient to allow one to align themselves with reality. Rationality is a method of thinking – a cognitive process of deduction, with which we can arrive at conclusions. And a rational conclusion won’t necessarily reflect reality, because it could easily have been derived from erroneous beliefs.

To hark back to our suicide bomber: his decision to blow himself up in a murderous attack was rational – it was just derived from a different framework of beliefs than we are accustomed to (i.e. AXIOM B, rather than AXIOM A).

He really believed that what he was doing was the will of Allah, and that paradise awaited him, and absolution awaited his victims. And with all of these beliefs in place, the course for his abhorrent actions was firmly set; it was the reasonable thing to do.

So then, because our own form of rationality is fundamentally the same as a suicide bomber’s, should we grant some kind of rational relativism – where his behavior is no less acceptable than ours?

Of course not. Not all beliefs were created equal.

What we truly care about, is making sure our beliefs mirror reality, and that, like the axioms of number theory, they are consistent.

After all, that is by definition what a belief aims to do; namely, to describe some real and true aspect of the world.

The terrorist’s actions are predicated on the assumption that his beliefs are true; and it turns out there is a way of confirming or falsifying those beliefs.

The Scientific Method

The scientific method can be thought of as some kind of marvelous machine that tests whether or not a belief mirrors reality.

Enter a particular hypothesis into the machine, and it can let us know, often with swift and irreverent certainty, that it is wrong. It does this by making empirical observations to test the predictions of particular theory.

We all have one of these machines – a crude version, at least – churning away inside us, with our senses serving as empirical instruments.

If you believe, for instance, that it currently raining outside, you can test this ‘hypothesis’ by simply going outside and seeing for yourself.

But clearly the human senses are imperfect; they only measure a small slice of the external reality. For example; we don’t detect electromagnetic radiation (light) outside of a certain narrow range; we can’t see things smaller than a certain scale; and even among the things we can detect, our senses are notoriously prone to getting it wrong – as you can easily demonstrate to yourself by looking at a few optical illusions.

Thus, in the practice of science, we must defer to hypersensitive instruments that don’t suffer from the same fickle limitations as our own senses – like Geiger counters, microscopes and seismographs.

So all of this is well and good – scientific observation can support or falsify certain beliefs, such as whether or not it is raining, and whether or not there are microscopic organisms living on your skin – but how can we possibly use it ‘measure’ the belief that Allah really exists, or that there is life after death?

In other words, how can we really be sure that our complex system of beliefs is a stable, accurate representation of the deeper, extra-sensory reality, and that an Islamic terrorist’s is not?

This is where consistency of one’s belief system becomes important, but there is more to it than that. A terrorist’s beliefs may well be consistent, but the true test of their accuracy lies in whether they possesses another key ingredient: constraint.

To illustrate this idea, we need to develop a more nuanced understanding of our own cognitive processes.

Because, though we might employ some of the same mechanisms used in formal logic, our minds do not bear the same simple, mechanical structure as a formal system.

We don’t possess a neat hierarchical tree of logic, with our foundational axioms (or beliefs) at the base, from which the flourishing and tangled foliage of our knowledge springs.

Instead, the neurological structure of our brains, and the isomorphic conceptual structure of our minds, is more like a chaotic lattice of interwoven, interrelated elements.

Conceptual Models

The idea of conceptual models or frameworks is of vital importance in understanding and talking about many complex topics – some of which we have written about, and some we will visit in future articles.

The entirety of your knowledge exists within a kind of self-supporting framework of interconnected concepts.

For example, lets say you wanted to rigorously define what a ‘book’ is.

You would invariably describe it in terms paper, words, language, ideas, pages, and a myriad of other such concepts.

And how would you describe these other concepts? In exactly the same way: for instance, you would define paper in terms of trees, and colour, and pulp, and.. books.

There is no escaping it – every concept is defined by other concepts, which are themselves defined by others, in a kind of self-referential, recursive tangle that collectively forms your entire framework of knowledge.

Thus, what is perhaps even more important than an individual concept – insofar as it makes sense to refer to it as ‘individual’ – are the relationships between concepts; how they interact with each other to form fully functional models.

For example, you might have a conceptual ‘model’ for the phenomenon of rain.

The model is built from other related concepts – like water, and evaporation, and condensation, and clouds, and temperature and pressure – and describes the process through which these different elements interact; i.e. the relationships between them.

A model can be thought of as a little machine, with thousands of moving parts – each of which works in perfect concert with the others.

And there are a plethora of these little machines tangled up within your framework of knowledge, such that there is a kind of harmonious operation not just within, but also between different models – the gestalt of which forms even larger, and more intricate models.

To make this more concrete, consider another model you might possess – a molecular model of H2O – which you could use to complement your aforementioned rain model.

This new model features concepts like atoms, and bonds, and chemical and kinetic energy. It provides complementary support for your rain model – allowing you to draw from it to explain some aspect that was otherwise taken for granted – such as the molecular mechanism by which water is transformed into vapour.

Now, with this characterization in place, we are in a position to understand the crucial difference between a scientifically minded person’s conceptual framework, and that of an Islamic terrorist.

Constraining rationality

Cast your mind back to a time before the scientific revolution.

In this benighted era, rain was an inexplicable miracle. In their ignorance of evaporation, molecules and energy: people did not possess the kind of mental models of rain that we do.

This may not seem so consequential – after all, how often does our knowledge of the molecular mechanism of rain actually help us? But there is actually a treacherous consequence that can arise when one is in possession of such a barren conceptual framework – namely, there is plenty of room to confabulate.

What this translates to in a literal sense, is an ability to impose your own theoretical interpretations onto a desolate model, which cannot easily be disproved.

So, in the pre-scientific age, it would be easy to impute some imaginative and un-falsifiable model with which to explain rain.

For example, in your benighted audacity, you might proclaim that rain is the manifestation of a capricious god’s rage; that, in response to some egregious human activity, god is expressing his immense displeasure for all to see, in the tangible form of falling raindrops.

This model might have seemed logically sound – especially if you could also correlate some terrestrial activity – say, the drunken revelry of their village – with the onset of rain.

But the fact is, the theory lacks the fine-grained structure of modern theories of rain – and so all of these explanatory ‘gaps’ can be filled in with religious confabulations. The model retains its ‘rational’ core, through virtue of being so vague that its axioms and conclusions have plenty of wiggle room with which to fit together.

For example, in this model, there is no need to explain where the rain clouds came from – they simply emerged by god’s magic. And even if it was known that the water rose from earthly sources, there would be no call to explain how it did so: ‘god’s magic’ is a sufficient explanation.

The pieces of this conceptual framework are rather like a jigsaw where the gaps are very wide, and the links very small. And as we’ll see, many different, but equally valid theories can fit into the gaps.

To illustrate this, let’s postulate an alternative theory of rain that might have been propounded in the past –  that rain is a reflection of god’s sadness. Perhaps he had witnessed some earthly tragedy – the death of a devout villager, say, and had opened the heavens in doleful sympathy for the loss.

This theory is equally as compelling as the ‘angry god theory’, and as such, neither has any more credibility than the other – one can simply substitute one jigsaw piece for another, into the enormous gaps in the model.

And when there is no reason to favour one over the other, the best course of action is to accept neither.

But now consider trying to defend one of these theories in light of what we know about the world today.

Not only would it have to be compatible with our ordinary observations of rain, but it would also need to fit in with our scientific models, developed through experiments that have revealed the nature of molecules, the transfer or energy, and other well studied phenomena. And given that we understand essentially all of the moving parts of the overall scientific model of rain – how it is driven by heat energy provided by the sun, causing evaporation of surface water, and condensation into clouds – there is no space in the model to insert a god’s influence.

Wherever you suppose you might fit him in, further research will disabuse you of the impulse to do so. Like a well-designed clock with its intricate array of small pieces, the scientific model operates perfectly – without recourse to a god’s magic.

Thus, the richer, and more intricate the model – the more it becomes a jigsaw puzzle where all the pieces snap nicely together, and cannot be easily supplanted by alternative ones, without compromising the entire picture.

In order to work within the system of rationality imposed by these myriad interconnected concepts, then, we must give up much of the freedom of movement that was available before we filled in the gaps.

Coupled with empirical support, this constraint is what elevates a scientific worldview above a religious one.

A belief in the religion of Islam, for instance, is hopelessly impossible to reconcile with a sufficiently fine-grained scientific worldview – the pieces just don’t fit together.

True faith requires you not to try to fit these disparate pieces – of religious dogma, and scientific models – together, because in doing so you would quickly see that they do not mesh.

But then, how do we explain the multitudes of devout Muslims, or Christians, that do also appreciate the scientific worldview?


 Up until now, we’ve been speaking of our ‘framework of beliefs’ or ‘system of conceptual models’ as if it’s this single cohesive mass sitting within our brain, and through which any thought we might have is filtered, and checked exhaustively for contradictions.

But unfortunately, the human mind isn’t quite so robust. We have the capacity to seal off different aspects of our worldview into isolated nests, so that a collection of distinct and perhaps incompatible models can co-exist in any one person’s mind.

When you have a thought – any thought – you won’t typically scrutinize it too closely. You won’t parade it in front of every little conceptual model you have nestled within your cognitive structure to see if there are any contradictions.

For example, let me present to you a fact that you might ordinarily accept without question – if you perceived that the source was sufficiently credible:

“If every human on earth stood one on top of the other, we would extend 50 billion feet into the air – the distance from earth to mars!”

Sounds plausible right? You probably wouldn’t even question this ‘fact’ – you’d just insert it right into the machinery of your framework of knowledge without a second glance, ready to be accessed, or more likely, forgotten, at some point in the future.

Yet, if you had examined it with a little more suspicion, you might have found that it didn’t quite mesh with some other beliefs you have lying around somewhere in your noggin.

For instance, you probably know that the human population is no more than 8 billion, and that the average height cannot be more than 6 foot, so if you had bothered to check the validity of the presented fact with a simple calculation, you would have instantly concluded that it cannot be true.

Or you might know that the true distance from earth to mars is much greater than 50 billion feet – and so there is another clash of incompatibility.

The point is, it’s disconcertingly easy to accept new information that is incompatible with some of your pre-existing beliefs.

And in this same manner, it is even possible to form self-supported ‘islands’ of beliefs that do not necessarily interact with each other, and so you might hold several conflicting worldviews at once. Thus any one person may have many contradictory systems rationality within which they can think.

This is one means by which a deeply religious person can also possess a nuanced understanding of physics without having their faith crippled by incompatible notions: in general, these two worldviews are kept isolated from one another, and no serious attempt is made to connect them via a robust network of relationships, such as one might build between their molecular and macroscopic models of rain.

What’s more, is that the particular framework that is accessed in any given situation is liable to be influenced by the brain’s emotional state. This phenomenon is called ‘motivated reasoning’, and occurs when the brain implicitly tries to optimize its own emotional state, and so, in some sense funnels thought through whichever framework of knowledge will produce conclusions that support the positive emotional state.

This is a mechanism not only by which religious people maintain their faith, but which also influences peoples’ arguments and beliefs in other emotionally salient domains – such as in politics, or any heated argument.

Our upcoming article will explore this phenomenon: how it works, and how we can mitigate its effects in the service of intellectual honesty.


What we have seen is that rationality is a process, applied to existing beliefs to produce new ones. There is, therefore, no guarantee that a conclusion reached through rational reasoning will be accurate, since the underlying beliefs on which it is predicated may not themselves be accurate.

In order to formulate a robust, accurate belief system, it is not only essential to empirically test them, but to ensure that they are sufficiently detailed, or constrained within a tight, mutually supportive conceptual structure – where only a single interpretation is possible.

This conception of rationality is no mere intellectual trifle: it is essential to understand, in order to combat worldviews that are antithetical to peace and progress.

The wrong worldview can manifest in death in destruction – and we won’t get anywhere by decrying such abominable actions as irrational.

Understanding how human rationality operates allows us to glimpse the true cause of many of our actions – and to ensure the validity of those actions, by attending to the integrity of their underlying foundation of beliefs.


  1. Interesting!

    What I am a bit uncomfortable, though, is the extent, to which the model of rationality you’ve proposed is individualized. If I understood correctly, as long as the system of beliefs we have created is internally consistent (i.e. each one is at least not contradictory with others), by definition it is rational. There is only question of their internal complexity and robustness, which determines the axiological hierarchy of them.
    What is problematic for me is the fact that the logical sentence ‘false implies false’ is always true. In other words, if we had a system with all false beliefs in there, the whole system would be rational in the sense, that nothing would be contradictory to anything else. Philosophical idealists, e.g. Kant, to avoid such a problem, introduced another level of consistency, i.e. all beliefs must be agreed not only internally, within one human being, but also externally, across all human beings.

    I have also an impression that there is a tacit assumption behind this essay, that the full scope of rationality can be perceived by the scientific method. What if that’s not true? Let’s assume some portion of rationality can be perceived only through philosophy and/or theology. In that case, we would need to incorporate religious/philosophical beliefs in the rational system we represent. And there is little to no evidence that the methodology of science should be equaled with the ontology of rationality.


    1. “In other words, if we had a system with all false beliefs in there, the whole system would be rational in the sense, that nothing would be contradictory to anything else. Philosophical idealists, e.g. Kant, to avoid such a problem, introduced another level of consistency, i.e. all beliefs must be agreed not only internally, within one human being, but also externally, across all human beings.”

      You’re absolutely right in that a system of beliefs might be consistent, but false.
      But I don’t think agreement across all human beings is a good way to ensure correctness. For example, imagine the religion Islam had conquered the world centuries ago, and so today almost everyone agreed that the Koran was the primary source of truth. They’d all be wrong.

      I think you understand, at least implicitly, what is meant by ‘false beliefs’ – namely, beliefs that can be refuted by empirical observation. No amount of agreement between humans can have any bearing on the truth or falsity of beliefs.
      The only reliable way to ascertain the accuracy of a model, is by testing the predictions made by that model – i.e. the scientific method.

      “Let’s assume some portion of rationality can be perceived only through philosophy and/or theology.”

      I’m going to assume you meant “some portion of REALITY…”
      I’m not sure why you need to throw theology in there – but philosophy? Sure.
      As much as many scientists deny it, a good part of science actually IS philosophy. But I’ll assume that the distinction you’re making is that science necessitates observation, and philosophy is simply the application of rationality (but is still beholden to empirical evidence).

      If you agree with those definitions, then hopefully you’ll see that I’m not tacitly assuming that science alone can lead us to truth – we also need philosophical (rational) reasoning to get us there.

      If you want to throw theology into your models, go ahead – but remember, if it’s possible to formulate a different model, which is equally compelling in terms of its accordance with empirical observation – then there’s no good reason to favour the theological model.


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