The central claim
I reject the widely assumed claim that every Cartesian idea, merely in virtue of being an idea, contains objectively real representational content (OR).1To see the many Cartesian commentators who hold either that all ideas contain objective reality or the weaker thesis that all ideas are representational, see my “Cartesian Commentators on the Status of Ideas.”
That universal thesis is too strong. Descartes’s purely strict ideas contain objective reality because they internally represent something as the object of thought. By “objective reality representational content,” I mean the representational content constituted by Cartesian objective reality, namely, the content a mental state has insofar as it internally represents something as the object of thought. But Descartes also uses “idea” more broadly for modes or forms of consciousness, including sensations, emotions, volitions, appetites, and other mental occurrences whose distinctive character is not exhausted by objectively real representational content. Some such states can nevertheless have an OR-bearing representational aspect. A fear of a lion, for example, is one broad-sense idea with an OR-bearing lion-representing aspect and a non-OR-bearing affective aspect of fear.
See my posts:
See the complete uncondensed version “Why Objective Reality Cannot Be Descartes’s Universal Theory Of Thought: Burman, Common Notions, And The Failure Of The Strict-Idea Model”
and its companion piece “Why Objective Reality Cannot Be Universal In Descartes’s Theory Of Ideas: Nothing, Eternal Truths, Sensations, And Fear With Claude Opus 4.6.”
The central DTOI claim is therefore this:
Cartesian secondary-quality sensations, such as cold, heat, color, taste, odor, and pain, are genuine ideas in a broad sense, but their phenomenal secondary-quality content does not contain objective reality.
They are formally real modes of mind. They occur. They are consciously felt. They may be vivid, useful, and practically indispensable. But their reality as mental modes is not the same as objective reality. Objective reality is the representational being an object has in the intellect when an idea internally represents it. Mere conscious presentation is not enough. A cold sensation does not contain cold objectively in the intellect. It presents or exhibits phenomenal coldness as a mode of consciousness. Were the phenomenal coolness to be a representation of coolness it wouldn’t feel cool.
Why the issue matters
This question matters because it affects the interpretation of nearly every central issue in Descartes’s theory of ideas: objective reality, sensory representation, material falsity, obscure and confused perception, the mind-body union, the causal principle in Meditation III, and Descartes’s denial that God is a deceiver.
If the phenomenal secondary-quality content of sensations possesses objective reality, then materially false sensory ideas seem to contain God-caused representational content that misrepresents the world. That is a dangerous result. It threatens to make God responsible for systematic sensory misrepresentation. If, however, the phenomenal content of sensations is presentational rather than representational content constituted by objective reality, then Descartes has a better option: sensory ideas can be materially false because their presentational character supplies matter for false judgment without itself constituting objectively real representational content.
The sensation of cold, for example, is not a judgment that cold exists in the ice. Nor does its phenomenal coldness internally represent cold as a positive quality in bodies. The sensation is a positive, formally real mode of mind whose phenomenal character presents coldness and naturally inclines the mind to take that coldness as if it were something in bodies. The error occurs when the intellect takes the phenomenal coldness presented in sensation to correspond to a positive quality belonging intrinsically to body.
Strict and broad uses of “idea”
The universal-OR interpretation typically depends on moving without sufficient qualification between Descartes’s strict and broad uses of “idea.” Descartes sometimes uses “idea” strictly for a thought insofar as it internally represents a thing as its object. In this strict use, “idea” picks out the thing-representing aspect of thought, the aspect whose objective reality can be compared with the formal or eminent reality of its cause. In the Third Meditation, Descartes characterizes such thoughts as tanquam rerum imagines, “as it were the images of things” (AT VII 36–37; CSM II 25–26).
The continuation of this passage is especially important for DTOI. Descartes contrasts these strictly so-called ideas with thoughts such as willing, fearing, affirming, and denying. These are not presented as a second idea added to an independently occurring strict idea. Rather, the same thought takes something as its object while having an additional form: “my thought includes something more than the likeness of that thing” (AT VII 37; CSM II 26). This structure fits the DTOI analysis of a fear of a lion as one broad-sense mental state with an OR-bearing lion-representing aspect and a non-OR-bearing affective aspect of fear.
Strict use of “idea”: Third Meditation, AT VII 36–37; CSM II 25–26; Conversation with Burman, AT V 153; CSMK III 338.
Broad use of “idea”: Second Replies, Definition II, AT VII 160; CSM II 113; Third Replies, AT VII 181, 188; CSM II 127–128, 132.
Ideas and mental states as modes of thought: Third Meditation, AT VII 40–41; CSM II 27–28; Principles of Philosophy I.53, AT VIIIA 25; CSM I 210–211; I.65, AT VIIIA 32; CSM I 216.
The main references are these:
| Use of “idea” | Descartes passage | AT / CSM reference | Best interpretive use |
| Idea as the form of any thought | Second Replies, Definition II | AT VII 160; CSM II 113 | The strongest broad-sense definition: “idea” is not restricted to the strictly thing-representing use but extends to the form of any given thought. |
| Idea as whatever is immediately perceived by the mind | Third Replies, reply to Hobbes | AT VII 181; CSM II 127–128 | The clearest broad-sense reply: Descartes rejects Hobbes’s restriction of “idea” to corporeal images and explicitly counts mental states such as volition and fear among ideas insofar as they are immediately perceived by the mind. |
| Idea and the form of perception | Third Replies, later reply to Hobbes | AT VII 188; CSM II 132 | Reinforces the broad formal/perceptual use of “idea” rather than restricting the term to a corporeal or imagistic representation. |
| Thought as whatever we are immediately aware of | Second Replies, Definition I | AT VII 160; CSM II 113 | Provides the background definition of thought. Since thought includes operations of intellect, will, imagination, and sensation, Definition I establishes the range of conscious mental activity to which Definition II’s broad definition of “idea” can apply; it does not by itself prove that every such mental mode contains objective reality. |
| Thought as everything conscious in us | Principles of Philosophy I.9 | AT VIIIA 7; CSM I 195 | Important corroborating text for the broad conception of conscious mental activity; it is a “thought” text, not directly an “idea” text. |
| Thought as the principal attribute of mind | Principles of Philosophy I.53 | AT VIIIA 25; CSM I 210–211 | Provides the ontological basis for mental modes: thought constitutes the nature of thinking substance, and whatever belongs to mind is referred to thought. It does not by itself establish that every mode of thought contains objective reality. |
| Understanding, imagination, memory, volition, and other mental operations as modes of thought | Principles of Philosophy I.65 | AT VIIIA 32; CSM I 216 | Provides the more explicit modal taxonomy: understanding, imagination, memory, volition, and other mental operations are various modes of thought. |
| Ideas considered simply as modes of thought | Third Meditation | AT VII 40–41; CSM II 27–28 | Crucial formal-reality passage: ideas considered formally are modes of thought. The passage distinguishes that formal modal status from differences arising insofar as ideas represent different things; it does not by itself establish that every conscious mental mode contains objective reality. |
| Strict use: ideas as images of things | Third Meditation | AT VII 36–37; CSM II 25–26 | The principal strict-use text: the term “idea” applies strictly to the thing-representing aspect of thought. The immediate continuation is especially important because willing and fearing are described as thoughts that take something as their object while also containing an additional form. |
| Strict/narrow vs extended/broad use | Conversation with Burman | AT V 153; CSMK III 338 | Important explicit support for the strict/broad distinction: Descartes distinguishes the strict and narrow use of “idea” from an extended use that can include common notions. |
| Sensations regarded merely as sensations or thoughts | Principles of Philosophy I.68 | AT VIIIA 33; CSM I 217 | Important for DTOI: sensory states can be clearly and distinctly perceived when regarded merely as sensations or thoughts. This does not establish that their phenomenal secondary-quality content internally represents corresponding qualities in external bodies. |
The two anchor texts for broad Cartesian “idea” are therefore Second Replies, Definition II: AT VII 160; CSM II 113, and Third Replies to Hobbes: AT VII 181; CSM II 127–128. The first supplies Descartes’s broad formal definition, while the second confirms that he extends “idea” to immediately perceived mental states such as willing and fearing and does not restrict ideas to corporeal images.
Second Replies, Definition II: AT VII 160; CSM II 113.
Latin: Ideae nomine intelligo cujuslibet cogitationis formam illam, per cujus immediatam perceptionem ipsius ejusdem cogitationis conscius sum.
English: “Idea. I understand this term to mean the form of any given thought, immediate perception of which makes me aware of the thought. Hence, whenever I express something in words, and understand what I am saying, this very fact makes it certain that there is within me an idea of what is signified by the words in question. Thus it is not only the images depicted in the imagination which I call ‘ideas’. Indeed, in so far as these images are in the corporeal imagination, that is, are depicted in some part of the brain, I do not call them ‘ideas’ at all; I call them ‘ideas’ only in so far as they give form to the mind itself, when it is directed towards that part of the brain.”
Third Replies to Hobbes: AT VII 181; CSM II 127–28.
“I make it quite clear in several places throughout the Meditations, and especially in this very place, that I take the term ‘idea’ to stand for whatever is immediately perceived by the mind. For example, when I will or am afraid, I simultaneously perceive that I will or am afraid; and that is why I count volition and fear among my ideas. I used the word ‘idea’ because it was the standard philosophical term used to refer to the forms of perception belonging to the divine mind, even though we recognize that God does not possess any corporeal imagination. And besides, there was not any more appropriate term at my disposal.”
The best strict-use contrast is the Third Meditation: AT VII 36–37; CSM II 25–26, where Descartes characterizes strictly so-called ideas as tanquam rerum imagines, “as it were the images of things.” The immediate continuation is equally important: willing and fearing are single thoughts that take something as their object while including an additional form. That structure supports the DTOI analysis of a fear of a lion as one broad-sense idea whose lion-representing aspect bears objective reality while its affective aspect of fear does not. This passage should be paired with Conversation with Burman: AT V 153; CSMK III 338, where Descartes explicitly contrasts a strict and narrow use of “idea” with an extended use.
Third Meditation: AT VII 36–37; CSM II 25–26.
Latin: Quaedam ex his tanquam rerum imagines sunt, quibus solis proprie convenit ideae nomen \ldots Aliae vero alias quasdam praeterea formas habent: ut cum volo, cum timeo, cum affirmo, cum nego, semper quidem aliquam rem ut subjectum meae cogitationis apprehendo, sed aliquid etiam amplius quam istius rei similitudinem cogitatione complector.
English: “Some of my thoughts are as it were the images of things, and it is only these that are properly called ‘ideas’—for example when I think of a man, or a chimera, or the sky, or an angel, or God. Other thoughts have other forms as well: thus when I will, or am afraid, or affirm, or deny, there is always a particular thing which I take as the subject of my thought, but my thought includes something more than the likeness of that thing. Some thoughts in this category are called volitions or emotions, while others are called judgements.” (bold not in original)
Conversation with Burman: AT V 153; CSMK III 338.
“[Burman:] But we have an idea of nothing, and this is not an idea of a thing.
[Descartes:] That idea is purely negative, and can hardly be called an idea. In this passage I am taking the word ‘idea’ in its strict and narrow sense. We do also have ideas of common notions, which are not, strictly speaking, ideas of things. But this is a rather extended use of the word ‘idea’.”
For the ontology of these mental states, the most important supporting references are Third Meditation: AT VII 40–41; CSM II 27–28, together with Principles of Philosophy I.53: AT VIIIA 25; CSM I 210–211 and Principles of Philosophy I.65: AT VIIIA 32; CSM I 216. These texts establish the formal reality of mental modes as modifications of thinking substance. They do not by themselves establish that every such mode contains objective reality. That further claim depends on whether, and in what respect, the mental ate internally represents something as its object.
Third Meditation, formal reality of mental modes (AT VII 40–41; CSM II 27–28)
“In so far as the ideas are considered simply as modes of thought, there is no recognizable inequality among them: they all appear to come from within me in the same fashion. But in so far as different ideas represent different things, it is clear that they differ widely. \ldots Now it is manifest by the natural light that there must be at least as much reality in the efficient and total cause as in the effect of that cause. \ldots And this is transparently true not only in the case of effects which possess actual or formal reality, but also in the case of ideas, where one is considering only objective reality.”
Principles of Philosophy I.53 (AT VIIIA 25; CSM I 210–11)
“A substance may indeed be known through any attribute at all; but each substance has one principal property which constitutes its nature and essence, and to which all its other properties are referred. Thus extension in length, breadth and depth constitutes the nature of corporeal substance; and thought constitutes the nature of thinking substance. Everything else which can be attributed to body presupposes extension, and is merely a mode of an extended thing; and similarly, whatever we find in the mind is simply one of the various modes of thinking. For example, shape is unintelligible except in an extended thing, and motion unintelligible except as motion in an extended space; while imagination, sensation and will are intelligible only in a thinking thing. By contrast, we can understand extension without shape or movement, and thought without imagination or sensation, and so on.”
Principles of Philosophy I.65 (AT VIIIA 32; CSM I 216)
“Thought and extension can be regarded as constituting the natures of intelligent substance and corporeal substance; they must then be considered as nothing else but thinking substance itself and extended substance itself—that is, as mind and body. \ldots Thought and extension themselves have various modes \ldots Examples of modes of thinking are understanding, imagination, recollection, volition, and so on \ldots These more particular modes \ldots are best perceived if we regard them simply as modes of the things of which they are modes.”
These seven passages are the ones the two paragraphs actually invoke. The first pair supplies the broad definition and the explicit inclusion of willing and fearing; the Third Meditation plus Burman supply the strict tanquam rerum imagines contrast and the “strict and narrow” / “extended” terminology; I.53 and I.65 (with the formal-reality stretch of AT VII 40–41) supply the claim that willing, fearing, understanding, etc., are modes of thinking substance and therefore possess formal reality as modifications of that substance.
Presentation is not internal representation
DTOI distinguishes presentation from representation. A sensation presents or exhibits its phenomenal character in consciousness. Pain hurts; cold feels chilly; red appears red. But a representation of pain need not hurt, a representation of cold need not feel chilly, and a representation of red need not itself appear phenomenally red.
This is the phenomenological point at the center of the argument. Sensory character is not automatically objective content. The fact that there is something it is like to undergo a sensation does not prove that the sensation internally represents an object. Sensations have formal reality as modes. Their phenomenal character does not thereby acquire objective reality or become objectively real representational content.
Sensations can still be signs
The denial that the phenomenal secondary-quality content of sensations contains objective reality is not the denial that sensations have any world-directed role. Sensations can still function as natural signs. A cold sensation can be lawfully coordinated with certain configurations of matter in motion. Pain can be lawfully coordinated with bodily disturbance. Color sensations can be coordinated with optical and neurological conditions.
This is external or sign-representation, not internal representation constituted by objective reality. A sign need not resemble what it signifies, and its signifying role need not consist in internally representing what it signifies as objective content. It need only be lawfully, causally, or teleologically coordinated with what it signifies. Thus DTOI can accept that sensations represent in a broad sign-theoretic sense while denying that their phenomenal secondary-quality content is representational content constituted by objective reality.
Material falsity without objective reality
Material falsity is not formal falsity. Formal falsity belongs to judgment. A sensation does not assert anything. It does not say that cold is in the ice, that pain is in the foot, or that color is in the surface of the body. Yet a sensation can still be materially false because its own character supplies matter for error.
A cold sensation is materially false insofar as its phenomenal character presents a positivity that the intellect can mistake for a positive quality in bodies. It presents a non-thing as if a thing, not because it contains false objective reality representational content, but because its phenomenal character naturally supplies matter for false judgment. This preserves the pre-judgmental status of material falsity without making phenomenal sensory content itself either a false proposition or a God-caused misrepresentation.
The pressure on rival interpretations
The DTOI argument challenges three common strategies.
First, it rejects the universal-OR view. Not every mental mode called an idea contains objective reality.
Second, it rejects the hidden-content view. The phenomenal secondary-quality content of sensations is not latent intellectual content waiting to be clarified by reason.
Third, it rejects the misrepresentation view. Phenomenal secondary-quality content does not internally represent corresponding external qualities and then misrepresent them. It is presentational rather than internally representational, although sensations can still function as natural signs of bodily or environmental conditions.
The misrepresentation view is especially problematic. If the phenomenal coldness of a cold sensation constitutes God-caused objective reality representational content that systematically misrepresents cold as a positive external quality, then God seems responsible for sensory deception. DTOI avoids that result. God creates a mind-body system in which sensations function as practically useful natural signs. Their phenomenal character can supply matter for error without itself constituting false objective reality representational content. Formal error enters when the intellect judges that the phenomenal qualities presented in sensation correspond to qualities belonging intrinsically to body.
Recommended order of reading
This post provides the best starting point for the central DTOI argument. For the more technical statement of the underlying framework, see:
DTOI & Non-DTOI Baselines for AI Models
Then read the central cold-sensation arguments:
Proving that Cold Sensations Do not have Any Objective Reality to Bing’s Copilot
Proving sensations are ideas with no objective reality to ScholarGPT
How Cartesian cold sensations are or are not representational with Scholar GPT
For the broader theory of material falsity:
What Makes an Idea Materially False in Descartes’s Theory of Ideas?
For material falsity and Arnauld:
Privations, Sensations, and Objective Reality
For the God-deceiver problem:
Proving God is not a deceiver because sensations lack objectively real contents
For engagement with major sensory-representation interpretations:
Alison Simmons on sensations as representations and objective reality
Critiquing Raffaella De Rosa’s “Descartes on Sensory Misrepresentation”
The question for Cartesian scholars
The challenge for the universal-OR interpretation is straightforward: specify exactly what constitutes the objective reality representational content of a cold sensation. DTOI argues that every plausible candidate fails. The resulting conclusion is not that cold sensations are unreal, indeterminate, or cognitively insignificant. It is that their phenomenal coldness is not OR-bearing representational content.
See my post that defends this conclusion: “Why There Are No Successful Candidates For SQ-Sensations Objective Reality Content”
Cartesian SQ-sensations are broad-sense ideas, formally real mental modes, and natural signs of bodily or environmental conditions. But their phenomenal secondary-quality content does not contain objective reality. Considered with respect to that phenomenal content, they present without internally representing.
NOTES
- 1To see the many Cartesian commentators who hold either that all ideas contain objective reality or the weaker thesis that all ideas are representational, see my “Cartesian Commentators on the Status of Ideas.”
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