The central claim
My Descartes’s Theory of Ideas (DTOI) interpretation defended here denies a widely assumed thesis about Cartesian ideas:1To see the many Cartesian commentators who hold that all ideas have objective reality representational content or the weaker thesis that all ideas are representational, see my “Cartesian Commentators on the Status of Ideas.”
that every idea, simply because it is an idea, contains objective reality. That universal thesis is too strong. Descartes’s strict ideas contain objective reality because they internally represent 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 that are not strict object-specifying representations.
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 they do 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. A cold sensation does not contain cold objectively in the intellect. It presents or exhibits phenomenal coldness as a mode of consciousness.
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 sensations contain 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, sensations lack objective reality representational content, then Descartes has a better option: sensory ideas can be materially false because their presentational character supplies matter for false judgment without containing false objective content.
The sensation of cold, for example, is not a judgment that cold exists in the ice. Nor is it an intellectual representation of cold as a positive quality in bodies. It is a positive phenomenal mode that naturally inclines the mind to take cold as if it were a thing in bodies. The error occurs when the intellect treats the sensory presentation as a guide to the intrinsic nature of body.
Strict ideas and broad ideas
The universal-OR interpretation usually begins from an equivocation. Descartes sometimes uses “idea” strictly: an idea is as of a thing, an object-containing representation, the kind of mental item whose objective reality can be compared with the formal reality of its cause.
Strict sense of “idea”: Third Meditation, AT VII 36–37; CSM II 25–26; Conversation with Burman, AT V 153; CSMK III 338.
Broad sense of “idea”: Second Replies, Definition II, AT VII 160; CSM II 113; Third Replies, AT VII 181, 188; CSM II 127–128, 132.
Ideas as modes of thought: Third Meditation, AT VII 40–41; CSM II 27–28; Principles I.53, AT VIIIA 25; CSM I 210–211.
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, Definitions I–II | AT VII 160; CSM II 113 | The strongest broad-sense definition: an idea is not restricted to an image-like representational content but is “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 explicitly resists Hobbes’s restriction of “idea” to corporeal images and extends “idea” to what is immediately perceived by mind. |
| Idea as form of a given perception | Third Replies, later reply to Hobbes | AT VII 188; CSM II 132 | Reinforces the broad formal/perceptual sense: “idea” is tied to the form of perception, not merely to an imagistic representatum. |
| Thought as whatever we are immediately aware of | Second Replies, Definition I | AT VII 160; CSM II 113 | This supports the broad account only when paired with Definition II: if thought includes understanding, willing, imagining, and sensing, and idea is the form of any thought, then broad “idea” can range over those mental modes. |
| Thought as everything conscious in us | Principles I.9 | AT VIIIA 7; CSM I 195 | Important corroborating text for consciousness-modification language; it is a “thought” text, not directly an “idea” text. |
| Mental items as modes of thinking | Principles I.53 | AT VIIIA 25; CSM I 210–211 | Best ontological support: everything found in the mind is a mode of thinking; ideas, when considered formally, are mental modes. |
| Ideas considered simply as modes of thought | Third Meditation | AT VII 40–41; CSM II 27–28 | Crucial formal-reality passage: ideas as formally real mental modes can be treated apart from their objective-reality differences. |
| Strict sense: ideas as images of things | Third Meditation | AT VII 36–37; CSM II 25–26 | The principal strict-sense text: “idea” is strictly appropriate to thoughts that are “as it were images of things.” |
| Strict/narrow vs stretched/broad use | Conversation with Burman | AT V 153; CSMK III 338 | Important for the strict/broad distinction: common notions are not strictly ideas of real things, but “idea” can be taken more broadly. |
| Sensations regarded merely as sensations or thoughts | Principles I.68 | AT VIIIA 33; CSM I 217 | Important for DTOI: sensory modes can be clear and distinct when treated merely as sensations/thoughts, not as representing external qualities. |
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 gives the formal definition; the second proves that Descartes knowingly uses “idea” more broadly than Hobbes’s imagistic sense.
The best strict-sense contrast is Third Meditation: AT VII 36–37; CSM II 25–26, where Descartes says the term “idea” is strictly appropriate to thoughts that are tanquam rerum imagines, “as it were images of things.” That passage should be paired with Burman: AT V 153; CSMK III 338, where Descartes distinguishes the strict/narrow use from a broader or stretched use of “idea.”
For the ontology of the broad use, the most important supporting references are Third Meditation: AT VII 40–41; CSM II 27–28 and Principles I.53: AT VIIIA 25; CSM I 210–211. These support the claim that ideas, considered formally, are modes of thought, while differences in objective reality belong to ideas considered with respect to what they represent.
Presentation is not internal representation
DTOI distinguishes presentation from representation. A sensation presents or exhibits itself. Pain hurts; cold feels chilly; red appears redly. But a representation of pain does not hurt, a representation of cold is not chilly, and a representation of red need not be 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. They do not thereby acquire objective reality as representational contents.
Sensations can still be signs
The denial that sensations contain 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 by objective reality. A sign need not resemble what it signifies, and it need not contain its object as an internal intellectual 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 they contain 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.
Cold sensation is materially false because it presents a phenomenal positivity that the intellect can mistake for a positive quality in bodies. It presents a non-thing as if a thing, not by containing a false objective representation, but by exhibiting a sensory character that naturally invites false judgment. This preserves the pre-judgmental status of material falsity without making sensory content itself 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. Sensations do not contain latent intellectual content waiting to be clarified by reason.
Third, it rejects the misrepresentation view. Sensations do not internally represent external qualities and then misrepresent them. They are sensory presentations and natural signs, not confused intellectual depictions.
The misrepresentation view is especially problematic. If cold sensation contains God-caused objective 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 are practically useful signs. Error enters when the intellect misuses them as guides to the metaphysical nature of body.
Recommended order of reading
The best starting point is the baseline statement:
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 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
One quickly should discover that as soon as one tries to specify the objectively real representational content (OR) of a cold sensation all answers to this question fail except for one resolution. Secondary quality (SQ) sensations lack any objective reality content.
See my post that proves it: “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 secondary-quality sensations do not contain objective reality. They are sensations without internally representational content.
NOTES
- 1To see the many Cartesian commentators who hold that all ideas have objective reality representational content or the weaker thesis that all ideas are representational, see my “Cartesian Commentators on the Status of Ideas.”
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