⚠ It doesn't make much sense to answer this question if you are not acquainted with Gabriel's work and do not even read the linked interview.

I always thought that common sense is fundamentally different from the information-gathering systems we have, like the sense of sight. Sounds ironic, but as we'll see, not everyone agrees.

Sense is simply equivocal, and can also mean the ability to judge or understand something.

In his book The Meaning of Thought, Markus Gabriel takes a broad perspective on what we should understand by sense: we even should group the typical senses like sight, hearing, touch together with thinking. In an interview he gives a short summary (I encourage you to click on the link, read the whole section or even better the whole interview):

A sense* is a fallible way of being in touch with a mind-independent reality. In thinking about mathematics, we are in fallible touch with a mind-independent reality. If I make a calculation mistake, which is very easy in complex mathematics, then I get reality wrong. If I miscalculate a linear operator in quantum mechanics, I just make a mathematical mistake. Why not think, then, that I’m in touch, as a thinker, with a reality that cannot be grasped by any other sense?

Of course, you can define your terms any way you like. But I still see a few problems that naturally arise from removing the traditional distinction:

  • we must presuppose platonism of abstract objects
  • we can get the same information through different senses (we can touch or see the form of an object), but - as he admits - what we get by (generalized) thinking we cannot get by any other means
  • how can we understand that a sense organ gives us necessary truths (e. g. logical necessity)?
  • when we suffer sensory illusions, we believe to perceive what is in reality not there; but how can we understand illusions of abstract objects?

I feel that I'm missing good counterarguments. The idea proposed by Gabriel is so odd, I probably can't see the wood for the trees...

So what is wrong with the view outlined in the quote above? What would be better counterarguments?

* NB: in German sense is Sinn, and this term is similarly equivocal, meaning Verständnis (understanding) or Wahrnehmung (perception). I wonder if Gabriel could pull this off in a language that doesn't allow this.

  • The concept of senses is not a modern one, but a very old one storming from dualist worldviews like souls. Modern philosophy has no such consensus about dualism or the nature of the mind, and so the definition of senses it's more relevant in biology and psychology now.
    – tkruse
    Jan 21 at 10:50

6 Answers 6


I'm reading through the whole interview (that was a really good dialectical move, here, by the way: putting the alert at the head of the OP made me feel prospectively guilty about the thought of responding to the OP without reading the interview), so I'll respond in terms of this reading. Here is one earlier, highly relevant section:

Mathematics is a practice whereby you fully transcend yourself. You get the skills and the demonstrations, and at first you don’t understand them. Then, later, light begins to slowly illuminate the completely objective topics. Mathematics is never about the mathematician; philosophy is always also about the philosopher. It involves the thinker of those thoughts, whereas mathematics does not presuppose the thinker. Another difference is that in philosophical training, it’s important that the student understand the nature of every stage at that stage. In mathematics, conversely, it’s very important that you don’t understand the nature of the stage: just follow the rule blindly. That’s part of the skill.

Although probably (or almost definitely, as in the case of someone like Cantor) overstated, I think that he's getting at something true enough, and hence admitting of insightfulness enough, to contribute to his discourse on thought-as-a-sense and fields-of-sense further along. All this talk of stylish mathematics reminds me directly of the matter of mathematical style as a philosophical topic and then of the relationship between syntax, semantics, and semiotics in the domain of generalized metalogical discourse.

He soon says:

My books are, as it were, accessible math books. Right now, I’m working on an accessible “philosophy of quantum mechanics” book, to figure out to what extent the deep mathematics of quantum mechanics can be explained in this way. Maybe they can’t. I don’t know yet.

That's a good sentiment to have, here ("good" as in virtue-epistemological terms, say). Also, in light of it, I suspect that the fields-of-sense concept is adapted from quantum field theory in some way. I'll see if that's so, but it was what I was struck with right from reading the phrase "fields-of-sense."

Next, the "crux":

We tend to draw distinctions between sensing and thinking, and the reason for this goes as far back as Plato and Aristotle. Here’s how the idea usually goes. Sense organs have their proper object: smelling is for smells, hearing for sounds, seeing for colors and shapes, and so forth. They have their proper objects, whereas thinking unifies these objects. If I think of a particular wine that looks yellow and tastes a little bit citrusy, then my thinking unifies the citrus taste and the yellow color. The idea was that since thinking synthesizes different sense impressions, it cannot be a sense organ itself — but that’s a straightforward non sequitur! It assumes that a sense organ is a sense organ because it has a proper object that can be synthesized in thinking. Why not assume instead, and this is my starting point, that thinking is an additional sense organ? Namely, the synthesizing sense organ, which is something that Aristotle explicitly entertains when he coins the concept of common sense (koinē aisthēsis in Greek, which will then become sensus communis in Latin, and “common sense” in English). The very idea of common sense, for 2,400 years, has been exactly the notion of thinking as a sense. That’s Aristotle preserved in the English language. I accept this idea, but I say that Aristotle made a mistake when he concluded that thought is not a sense. He should have developed and argued for the idea that thought is a sense — something he entertains in only two places in his work. So, what does this mean? How do we then understand a sense? A sense is a fallible way of being in touch with a mind-independent reality. In thinking about mathematics, we are in fallible touch with a mind-independent reality. If I make a calculation mistake, which is very easy in complex mathematics, then I get reality wrong. If I miscalculate a linear operator in quantum mechanics, I just make a mathematical mistake. Why not think, then, that I’m in touch, as a thinker, with a reality that cannot be grasped by any other sense?

On the one hand, again, it's a strong move on his part. You can frame what he's saying as a rejoinder to skepticism about senses like seeing. In other words, if even thinking is a sense, and the qualia of its sensations are things like syntactic relations or other metaphysical jargonified terms, then by some kind of anti-skeptical parity about the value of thought, we can see the value of seeing a priori anyway. (In fact, there was a whole debate around the time of Frege about whether the laws of logic, as laws of thought, represented necessary psychological truths, but still psychological truths; and J. S. Mill, for example, traced the law of noncontradiction to the sensation of truth-nullification involved in asserting and rejecting the same belief.) However, from his tone directly, I think his more crucial point, and error, is about how "the presupposition" of the non-sensory character of thought is a presupposition.

In Kant, for example, it is not that the senses are demarcated from thought on an intuitive basis, but he explains the dynamical reason for their differentiation on the relevant conceptual level. (For in Gabriel's terms, we can still differentiate thought from other senses, and even dynamically, perhaps; but he is using the word "sense" in a different sense(!) than Kant, then.) Sensations are passive or reaction, whereas thoughts are, as the procession of the understanding and reason, "spontaneous." You can critique the arguments and considered judgments that Kant builds this talk of spontaneity on, but I don't think it'd be fair to say that Kant was just presupposing that thinking is not a sense. Trivially or not, by his definitions, the word "sense" is better reserved for the deliverers of information like sight and hearing, and the interpreter of information, albeit in the spacetime forms a quasi-source of information in its own right, is then not the same as to be such a deliverer. If it were, Kant said, then such an entity would be equipped with intellectual intuition, which is the form of divine creation in abstracto. This is the ultimate reason why, in Kantian terms, thought is not a kind of sensation.

However, note that the whole strongly modern question of defending philosophical analysis by appeal to "intuitions," whether those of "trained philosophers" or the philosophy laity (the human laity overall, in fact), testifies to the residue of a conflation of the dynamical form of thinking with the dynamical form of sensing.

Now, Frege had the interesting idea that, given the plurality of isomorphic geometries, it would be possible for everyone in the universe to perceive reality according to a different geometrical theory, whereas their logic on their perceptions would not be so variant. This is in line with what Gabriel emphasizes about talk of common sense, as thought, here. Thought-as-an-objective-sense, or a more purely, fundamentally intersubjective one.

A further specifically interesting/relevant point in the interview:

The lowest hanging fruit is the recognition of what I call self-evident moral facts. They’re so obvious that we don’t usually dispute them...

Here, he sounds like a moral intuitionist, which is again an example, in the history of philosophy, of a thought-sensation merger perspective. Many, or maybe even all, moral intuitionists (not so called) before G. E. Moore were empirically minded about how this faculty operated, or what it operated upon, but Moore allowed that we could intuit certain facts of goodness through abstract speculations about worlds empty or full of certain things in certain ways (a world empty of consciousness but full of beauty, for the example I feel I can remember from him).

And as to fields-of-sense:

This is a crucial point. We need to reduce the transfinite, or what I now call “the hypercomplexity of fields of sense.” Reality is not just a form of complexity: it’s hypercomplex, and no mathematical model will be able to represent reality as such.

I really do think he has the relevance of QFT as a picture of objective reality in mind. QFT can be seen as a variation on the theme of the geometrical grounding, now the topological grounding, of macro-level objects: not point particles or even quite so much detached strings, but the algebraic zone whose localized solutions are functional equivalents of point particles, strings, branes more generally. He mentions an "algebra of normativity" in connection with this thematism, obliquely or not. But anyway, then a sense can be modeled in terms of fields, mathematically no less, but modulo hypercomplexifiers; and on this analysis of what the word "sense" means, it does make a lot of sense to interpret thinking as a sense. Sight is a field of color and geometrical information; hearing is a field of sound and geometrical/topological information; perhaps thought is a field of syntactic qualia and just topological, not "also" geometrical, information.

  • 1
    prospectively guilty about the thought of responding to the OP without reading the interview 😀 thanks for actually reading it and engaging with the views Gabriel actually promotes.
    – viuser
    Jan 22 at 17:16

This question is typical of so many in philosophy, in a which an ambiguous word is allocated yet another meaning with the result of causing disagreement with those who take the word to mean something else. For example, if you ponder the point through that lens you might decide that the long running controversy about whether or not Platonic objects exist should be dismissed as an argument at cross purpose about the meaning of the word exist.

For the sake of clarity, let us be clear that there is a meaning of the word sense which is to be aware of something through the body's five senses of sight, hearing, smell, touch and taste. If you wish, you can extend that conventional list to include other physiological senses such as your sense of balance which allows you to tell whether your body is at an angle.

There is then another meaning of the word sense which is to become aware through recollection, anticipation, imagination or cogitation. Taking that use of the word, I can sense that I had forgotten to send my brother a birthday car, that I will have to pay my tax at the end of the month, that I might enjoy a trip to a brewery and that objections to presentism based on the absence of absolute simultaneity in Special Relativity are misguided.

All of the issues you raise in your question disappear if you accept that Gabriel is simply conflating different uses of 'sense'.

To be more concrete, the five senses we conventionally attribute to humans play the role of interacting with external physical phenomena and converting that interaction into electrical inputs to the brain. The eyes interact with incoming photons. The ear interacts with vibrating aggregations of air molecules, and so on. There is a clear distinction between that common characteristic of the five senses- namely an interaction with physical effects external to the body- and the sensing of abstractions such as mathematics, where there is no external contact.

  • Yes, with clearer definitions and clearer questions, 50% of philosophy would disappear or appear to be just a matter of opinions. Taking into account questions answered by science, another 40% of philosophy would be gone. But of course, people love to speculate, so they would not be content with that :-)
    – Frank
    Jan 21 at 17:29

The view outlined in the quote above is problematic for several reasons. First, it presupposes platonism, which is the belief that abstract objects such as mathematical concepts exist independently of the physical world. This is a contentious position in philosophy and not all philosophers agree with it.

Second, the idea that thinking provides a way of being in touch with a mind-independent reality is not clearly explained. It is not clear how thinking can be considered a sense, as it is a cognitive process rather than a physical mechanism for gathering information.

Third, it is not clear how the distinction between necessary and contingent truths can be maintained if all senses are considered to be fallible ways of being in touch with reality. Logical necessity is typically considered to be a feature of the structure of reality, rather than a feature of the way we gather information about it.

Fourth, it is difficult to understand how illusions of abstract objects could be understood within this framework. Illusions are typically considered to be errors in perception, but it is not clear how this would apply to abstract objects.

Overall, the view outlined in the quote above is problematic and raises many questions that are not clearly answered. A more convincing argument would need to address these issues and provide a clearer explanation of how thinking can be considered a sense and how illusions of abstract objects can be understood within this framework.


For a contemporary physicalist (SEP), absolutely not. Other metaphysical frameworks might support it. I'm not familiar enough to argue them.

It's not odd for neo-Platonic thinkers, but certainly for anyone who has confidence in the physical sciences. But, I think it's important to unpack some things.

First, anyone can define a sense in, well, any sense they want. There is no governance of definitions. However, convention is mighty important, and conventionally, senses are taken to be part of the physicalist framework that describes a chain of causality which would be characterized in physical causal terms of transduction by the central nervous system for most empirically-minded thinkers. There are actually more than 5 senses under the current schema accepted in scientific circles when one differentiates touch or includes proprioception. But thinking isn't included among them. But, Platonic thinking, Christian dualist thinking, or the thinking about modal reality has, as far as I have known, never really provided anything more than the extended metaphor of thinking as sense. To be a literal sense requires some form of transduction or propagation of neural activity.

A neurologist can say, we understand how color is related to visual perception, and give you the mechanisms involved, including, say, the eyes, the optic nerve, the brain stem, the visual cortex, and the neocortex. In fact, there's a lot of data being accrued by fMRIs and other neuroimaging techniques that continues to pair phenomenal experience with objective, external events understood in terms of the physical sciences. Thus, for a physicalist to make a claim about being a sense, they are constrained by the overwhelming consensus of physicalists who study physics, chemistry, biology, neurology, medicine, and so on to declare a new sense. There's a paradigm that would have to be defeated. Neo-platonic thinkers, again to the best of my knowledge, never provide that sort of empirical grounding. They sort of wave their fingers in the air and appeal to inference to best explanation ambiguously usually relying on clever metaphysical arguments. For strict empirical thinking, such claims don't remotely pass the sniff test.

But philosophers are concerned with metaphysical speculation, and rightfully so. There's a rational basis for presuming altered states of consciousness might even be some sort of "conduit" to another physical realm. And considering that there are a lot of PhDs in physics and mathematics who seem to accept this, there seems to be a broad, political motivation for appealing to it. I speak of people like Seth Lloyd who partake in the sort of claims that are well beyond the reach of scientific experimentation. My take on it is that these positions are very rational and sophisticated, but seem to lack a basic understanding of the history and methods of the physical sciences. So in other words, I find such claims epistemologically sloppy, and I also think the ontology is excessive. But, there's nothing wrong with speculation as long as it is acknowledged as pseudo-scientific.

The basis for rejecting these alternate physical realities lies in the concept of burden of proof. If you make a claim about a physical entity or property, you must simply provide empirical evidence it exists. If you do not, or cannot, then it doesn't. This was the essence of Russell's teapot. It is also a leitmotif of Karl Popper and his quest to convert people to falsifiability. For ten thousand years, confident people have been running around making claims about reality, but not until the scientific revolution and particularly science of the 20th century, have modern day empiricists so thoroughly guarded the gates of the ontological (at least in one segment of thinkers in the Western world under the guise of Continental and analytical philosophy). Any claims that your brain has a supernatural connection to alternate physical realities are nothing more than claims until empirical evidence can be presented. Mathematical realists are rational, organized, and quite learned, but they've never produced anything that can be construed as such. That's the argument to make. To some that smacks of scientism. To me, it just seems an adequately level of skepticism given the historical record and the current facts presented by psychology and science.

Of course, mathematical realists, advocates of the supernatural, modal realists, multiverse proponents, and the like have strong metaphysical arguments, so the best way to deflate them is to naturalize your epistemology. Bone up your philosophy of science by showing why scientific facts are the best basis for understanding the physical world. I'm not familiar with Popper's specifics (just received a copy of his Conjectures and Refutations, but I read Kuhn's Revolutions, and if you want to deflate fantastic claims of ontological Flatlands, drag the conversation back to psychology and sociology. Drive home the point that the logical is rooted in the psychological, because as best as physical science can show, there are no minds without brains.


One thing that could be argued to be wrong is when the author asserts "In thinking about mathematics, we are in fallible touch with a mind-independent reality". It could be questioned whether mathematics is concerned with "mind-independent reality", rather than "mind-dependent concepts".

But a lot is going to ride on what is understood by "reality". After all, you could argue that only Ideas are "real" and whatever we perceive by any other sense than thinking is an illusion, or you could conversely deny that Ideas have any "reality" at all. This author seems to make a strong commitment to some form of Idealism. But we would need more details to see the details of the author's position. Besides mathematics, would he go as far as saying that whatever we can think of is real, for example?

Also, it would probably be useful to separate senses from organs that give us "sense impressions" as a result of some signal impinging on our sensory organs from thinking that presumably can be carried out without being triggered by any stimulus from a traditional, biological sense organ. The demarcation seems to be that a sense provides an input to our consciousness as a consequence of some event outside that consciousness, whereas thinking can unfold inside the consciousness without external stimulus.

  • 1
    Did you read the full interview? He goes into more details there. Also, Gabriel introduced the ideas of fields of sense in ontology - strange entities we can presumably perceive, too. He defines existing as "existing in a field of sense".
    – viuser
    Jan 21 at 12:30

Can thinking be a sense?

No more than running or digesting or breathing is a sense.

we must presuppose platonism of abstract objects

No. We only have to recognise that we have thoughts and this is easy because are aware of them.

we can get the same information through different senses (we can touch or see the form of an object)

No. We don't get the same information through different senses. Instead, our brain learns to correlate or associate different informations as being about the same object and somehow confirming each other.

what we get by (generalized) thinking we cannot get by any other means

We cannot get colours through our ears either.

how can we understand that a sense organ gives us necessary truths (e. g. logical necessity)?

Logical truths are not necessary. We only have one logic, so we cannot deny, say, the modus ponens without being either illogical and equivocal in our premises, à la McGee.

We are usually unable to see anything in colours different from red, blue etc., yet some people can.

It is unclear whether anyone can really think of the modus ponens as false without being somehow deranged.

when we suffer sensory illusions, we believe to perceive what is in reality not there; but how can we understand illusions of abstract objects?

This is the point. Abstract objects precisely do not exist outside our mind, so if we are nonetheless aware of them, it has to be because we have a specific sense, namely, that of being aware of our ideas as contents of our mind.

We can similarly distinguish other senses such as our perception of our own memories, feelings and logical intuitions (intuition for example that the modus ponens is true). Memory can be seen broadly as the sense of past experience (or past perception), while our logical intuitions can be seen as our sense of perception of the logical relations validated by natural selection.

So, it is not thinking which is a sense, but thinking obviously relies on more senses than our senses of perception of the current state of the world outside our skull.

  • 1
    We don't get the same information through different senses. I can identify a bottle by sight. I can close my eyes and identify a bottle by touching. This was the point. How would you describe this?
    – viuser
    Jan 21 at 12:19
  • @viuser "How would you describe this?" I already did. Jan 21 at 16:36
  • Don't know what you mean, please repeat.
    – viuser
    Jan 21 at 16:45

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