Strict and Broad Ideas in DTOI

June 29, 2026

Introduction

Few interpretive issues in Descartes’s theory of ideas have generated more confusion than his use of the word idea. Modern commentators (and probably all earlier ones too!) frequently assume that the term has a single, univocal meaning throughout his writings and consequently conclude that every Cartesian idea is intrinsically representational, contains objective reality, or functions as an internal image of something.¹ Yet Descartes himself repeatedly employs idea in more than one sense. Sometimes he uses it narrowly (strict ideas) for thoughts that are tanquam rerum imagines—“as if images of things”—whose defining feature is that they internally represent a substance, attribute, nature or essence, or mode. At other times he employs idea far more broadly (broad ideas) for any immediate conscious modification of thought, including sensations, passions, volitions, and other mental acts that need not contain an internal representatum at all.

The failure to distinguish these two senses has produced a remarkable number of interpretive difficulties. It encourages the assumption that every conscious state must possess objective reality, obscures Descartes’s explanation of material falsity, conflates phenomenal presentation with internal representation, and makes his treatment of sensations appear inconsistent. Once the distinction between strict and broad ideas is recovered, many of these puzzles either disappear or become substantially easier to explain.

The purpose of this post is therefore not merely lexical. It argues that the strict–broad distinction provides the conceptual framework within which Descartes’s theory of ideas becomes internally coherent. Strict ideas are the bearers of objective reality because they contain an internally represented representatum. Broad ideas, by contrast, are conscious modes of thought whose primary role may simply be to present themselves phenomenologically or to function as law-governed signs without internally representing anything through objective reality. Recognizing this distinction clarifies why only some Cartesian ideas enter the causal argument of the Third Meditation, why sensations can remain genuine ideas while lacking objective reality representational content (OR), and why the representational structure presupposed throughout Descartes’s theory of ideas (DTOI) differs fundamentally from the interpretation commonly attributed to Descartes.

Why this passage matters in the Third Meditation

“Some of my thoughts are, as it were, the images of things, and it is only in these cases that the term ‘idea’ is strictly appropriate—for example, when I think of a man, or a chimera, or the sky, or an angel, or God. Other thoughts have various additional forms: thus, when I will, or am afraid, or affirm, or deny, there is always a particular thing which I take as the object 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 judgments.” (Meditations on First Philosophy, Third Meditation: AT VII 36–37; CSM II, 25–26)

Quaedam ex meis cogitationibus tanquam rerum imagines esse videntur, quibus solis proprie ideae nomen competit: ut cum hominem, vel Chimaeram, vel Coelum, vel Angelum, vel Deum cogito. Aliae vero alias quasdam formas praeterea habent: ut cum volo, cum timeo, cum affirmo, cum nego, semper quidem aliquam rem ut objectum meae cogitationis apprehendo, sed aliquid etiam amplius quam istius rei similitudinem cogitatio mea continet. Et ex hoc genere cogitationum aliae voluntates, aliae affectus, aliae judicia vocantur. (AT VII 36–37):

The phrase “tanquam rerum imagines” (“as if images of things”) carries the famous “as if” [tanquam] qualifier that signals Descartes is speaking analogically: ideas in the strict sense are like images, not literally pictures in the mind. The “additional forms” (alias quasdam formas praeterea) mark the non-representational overlay—volitions, emotions, and judgments—that turns a bare idea into a full mental act.

Descartes surgically restricts the term ‘idea’ strictly to those thoughts that possess objective reality (internal representational content) because “image-like” thoughts can later be weighed for their degrees of objective perfection and subjected to the causal adequacy principle (a cause must contain at least as much reality or perfection as it imparts to its effect). Volitions, fears, affirmations, and denials, by contrast, contain an extra formal component (the act of willing, fearing, etc.) that is not itself representational.

The passage foreshadows the later discussion of material falsity (and ideas/sensations of secondary qualities) and the “strict idea model.” Descartes does not limit his use of idea only strictly but often broadens its use to contents of awareness when thinking.

Michael Moriarty’s Oxford World’s Classics translation (2008, p. 25) renders the key opening quotation almost identically: “some of my thoughts are as it were the images of things,” preserving the “as it were” and the strict-proper-use of idea. The rest of the paragraph follows the same logical architecture as CSM, though with slightly more contemporary phrasing in the list of ‘additional forms.’”

This passage is foundational for my interpretation. Let me draw out why it’s so damaging to the weaker universal representational thesis that all ideas are representational.

Descartes’s taxonomy of thought here is tripartite, not merely bipartite (strict or broad ideas):

Strict representational ideas—ideas strictly so called, or thoughts that are tanquam rerum imagines, “as if images of things.” These alone properly bear the name “idea” in Descartes’s narrow sense. They contain an internal representatum and therefore carry objective reality. Examples include the ideas of God, mind, body, extension, triangle, a chimera, and a particular person or object. AT VII 36–37; CSM II 25–26.
Simple non-representational presentations—conscious mental modes whose intrinsic phenomenal or affective character is immediately presented to awareness but which contain no internal representatum and therefore no objective reality. Secondary-quality sensations such as cold, pain, color, sound, taste, and smell belong here on the DTOI interpretation. So may generalized fear, free-floating anxiety, or joy considered simply as felt states, when no determinate object is represented. Such states can still possess phenomenal character, affective directedness, bodily location, practical significance, or external causal relations without internally representing a thing through objective reality.
Composite intentional acts—volitions, emotions, and judgments that combine a strict idea with an additional formal act. Fearing a lion, willing to raise one’s arm, affirming that snow is white, and denying that bodies exist each contain a representational idea as one constituent while adding the non-representational form of fearing, willing, affirming, or denying. Descartes accordingly says that such thoughts “include something more than the likeness of that thing.” AT VII 36–37; CSM II 25–26.

This taxonomy classifies kinds and structures of thought, not three coordinate species of strict ideas. The first category consists of strict ideas that contain objective reality. The second consists of simple conscious presentations that lack objective reality altogether. The third consists of complex acts that unite a strict representational idea with an additional non-representational formal element.

Descartes is therefore explicitly committed to the claim that not every constituent or feature of thought is representational in the objective-reality-bearing sense. The act of willing, fearing, affirming, or denying is not itself another image-like representation of the object. It is a genuine formal constituent added to the representational idea. The representational nucleus and the additional formal act must therefore be distinguished even when they occur together within a single complex thought.

If Descartes already acknowledges non-representational constituents within composite mental acts, then the universal principle that “all thought is representational” cannot be extracted from this passage. What the passage supports is a more discriminating account:

Only strict ideas are intrinsically representational in the objective-reality-bearing sense.
Some conscious states are simple presentations that lack any internal representatum and contain no objective reality.
Other mental acts are composite: they contain a strict idea but are not reducible to that idea because they also include a further formal act.
The additional formal constituent is real and irreducibly non-representational, even when the whole act is directed toward an object represented by its strict-idea component.

A defender of a weaker universal representational thesis might reply: “But Descartes says that in volitions, emotions, and judgments there is always ‘a particular thing which I take as the object of my thought.’” In ordinary object-directed cases, that is correct. Fearing a lion, loving a friend, willing to travel to Paris, or affirming that snow is white each contains a strict representational idea. But this concedes the relevant point rather than refuting it. The internal representation belongs to the strict-idea constituent, while the fearing, loving, willing, or affirming contributes an additional formal element that is not itself another representation of the object.

Nor should every affective state be forced into this composite structure. Generalized fear or free-floating anxiety may be consciously experienced without any determinate object being internally represented. Such a state can still have affective directedness, urgency, bodily phenomenology, or practical significance without containing an objective-reality-bearing idea of some thing feared. This shows why “intentionality” must not simply be equated with the possession of an internal representatum. A mental state may be phenomenally or affectively directed without representing a res through objective reality.

The significance for DTOI is immediate. A secondary-quality sensation need not be analyzed as a composite act consisting of a strict idea plus some additional sensory overlay. If the sensation of cold contains no internal representatum—if no substance, quality, nature, or mode is represented within it through objective reality—then it falls outside the strict representational core altogether. It is a simple, formally real mode of mind whose phenomenal character is immediately presented to consciousness without an image-like representational nucleus.

DTOI therefore distinguishes three importantly different structures: a strict idea containing objective reality; a simple conscious presentation lacking objective reality; and a composite act containing both a strict representational idea and an additional non-representational formal constituent. The deepest dividing line is not between intentional and non-intentional thought in every possible sense of “intentionality.” It is between thoughts that contain an internal representatum and thoughts that do not. Composite acts straddle that divide because they unite a representational constituent with a non-representational one.

See my supporting posts:

“Do Cartesian Sensations Have Objective Reality? Strict Ideas, Broad Ideas, and Material Falsity in Descartes’s Theory of Ideas”

“How My DTOI Baseline Accounts For The Material Falsity Of Secondary Quality Sensations”

“Convincing ChatGPT 4.0 (April 2023 version) that Cartesian secondary quality sensations (SQS) have no objectively real mental content – (Maybe it will convince you, too!)”

“Convincing Anthropic’s Claude.ai that Cartesian sensations lack objective reality”

“Conversation on representation & the material falsity of ideas with ChatGPT 4.0 (April 2023 version)”

DTOI therefore distinguishes three importantly different structures: a strict idea containing objective reality and an internal representatum; a simple conscious presentation lacking both objective reality and any internal representatum; and a composite act containing a strict representational idea together with an additional non-representational formal constituent. The deepest dividing line is therefore not between intentional and non-intentional thought in every possible sense of “intentionality,” but between conscious states that contain an internal representatum and those that do not. Composite acts straddle that divide because they unite an objective-reality-bearing representational constituent with a formally real constituent that does not itself contain an internal representatum.

So the passage does double work for my interpretation.

First, it shows Descartes himself restricting “idea” in the proper sense to representational, objective-reality-bearing thoughts—that is, to thoughts containing an internal representatum—which directly undermines any universalizing reading.
Second, it establishes a precedent for conscious mental states that lack any internal representatum within Descartes’s own framework, making it far less surprising that secondary-quality sensations, common notions, and the idea of nothing should likewise fall outside the objective-reality-bearing representational apparatus.

The weaker thesis—that all Cartesian ideas intrinsically contain objective reality or an internal representatum—cannot survive a careful reading of this passage. At the very outset of the Third Meditation, Descartes distinguishes the field of thought from the field of strict ideas. Strict ideas alone carry the representational weight of objective reality, while other conscious modes either combine such ideas with additional formal constituents or lack an internal representatum altogether.

A. Strict-sense ideas: tanquam rerum imagines

The canonical strict-sense passage is Meditation III, where Descartes distinguishes those thoughts that are, as it were, images of things from volitions, emotions, and judgments.

“Some of my thoughts are, as it were, the images of things”

“it is only in these cases that the term ‘idea’ is strictly appropriate”

“when I think of a man, or a chimera, or the sky, or an angel, or God.”

Reference: Meditation III, AT VII 36–37; CSM II 25–26.

“Quaedam ex his tanquam rerum imagines sunt, quibus solis proprie convenit ideae nomen”

Reference: Meditation III, AT VII 37.

The immediately following contrast is crucial, because Descartes includes willing, fearing, affirming, and denying among thoughts, but not among ideas in this strict representational sense.

“Other thoughts have various additional forms”

“when I will, or am afraid, or affirm, or deny”

“my thought includes something more than the likeness of that thing.”

Reference: Meditation III, AT VII 36–37; CSM II 25–26.

“Aliae verò alias quasdam praeterea formas habent”

“ut, cùm volo, cùm timeo, cùm affirmo, cùm nego”

Reference: Meditation III, AT VII 37.

This is the strongest textual basis for saying that, strictly, ideas are those thoughts that function as likenesses or quasi-images of things: man, chimera, sky, angel, and God. The relevant strictness is representational or object-presenting, not imagistic in the corporeal-phantasm sense.

B. Objective-content sense: idea as the thing thought of objectively

A second passage does not use the word “strictly,” but it is central for the strict representational/objective-content sense of idea.

“an idea is the thing which is thought of in so far as it has objective being in the intellect”

“the idea of the sun is the sun itself existing in the intellect”

“not of course formally existing”

“but objectively existing.”

Reference: First Replies, AT VII 102–103; CSM II 74–75.

“objectivè in intellectu”

Reference: First Replies, AT VII 102–103; CSM II 74–75.

This is not the broad “any conscious mental act” sense. It is the objective-being sense: the idea is considered as the thing represented or intentionally present in the intellect.

Another place where Descartes appears to imply that all ideas are representational is in his Fifth Set of Replies, where he states:

“An idea represents the essence of a thing, and if anything is added to or taken away from the essence, then the idea automatically becomes the idea of something else. This Is how the ideas of Pandora and of all false Gods are formed by those who do not have a correct conception of the true God.” (AT VII 371; CSM II 256; bold italic not in original)

My interpretation is that in this context, Descartes was only talking about all strict ideas that are tanquam rerum imagines (as if an image) as representing essences, but not of all ideas generally speaking where we include his use of broad sense ideas as characterized below.

C. Broad-sense ideas: idea as form of any thought

The broadest formal definition occurs in the geometrical exposition appended to the Second Replies.

“Thought. I use this term to include everything that is within us in such a way that we are immediately aware of it.”

“all the operations of the will, the intellect, the imagination and the senses are thoughts.”

“Idea. By the term ‘idea’ I understand that form of any thought by the immediate perception of which I am conscious of that very thought.” [“Ideae nomine intelligo cujuslibet cogitationis formam illam, per cujus immediatam perceptionem ipsius ejusdem cogitationis conscius sum.”]

Reference: Second Replies, geometrical exposition, Definitions I–II, AT VII 160–161; CSM II 113–114.

“Thus it is not only the images depicted in the imagination which I call ‘ideas’.”

“I call them ‘ideas’ only in so far as they give form to the mind itself.”

Reference: Second Replies, geometrical exposition, Definition II, AT VII 160–161; CSM II 113–114.

“forma cujuslibet cogitationis”

Reference: Second Replies, geometrical exposition, Definition II, AT VII 160–161; CSM II 113–114.

This is the most important broad-sense definition: since thought includes will, intellect, imagination, and sense, and idea is the form of any given thought, “idea” is here extended beyond strict representational rerum imagines.

D. Broad-sense ideas: volition and fear counted among ideas

The most explicit broad-sense reply to Hobbes is in the Third Replies.

“I am taking the word ‘idea’ to refer to whatever is immediately perceived by the mind.”

“when I want something, or am afraid of something”

“I count volition and fear among my ideas.”

Reference: Third Replies, reply to Hobbes’s Fifth Objection, AT VII 181; CSM II 127–128.

This is the decisive passage for broad-sense ideas as objects or forms of consciousness. It confirms that willing and fearing can be counted as ideas without implying that they are ideas in the strict tanquam rerum imagines sense.

E. Broad-sense ideas: ideas in the will, not merely in the intellect

Descartes also makes clear in correspondence that “idea” extends to the will as well as to the intellect.

“we have ideas not only of all that is in our intellect, but also of all that is in the will.”

“we cannot will anything without knowing that we will it”

“I do not claim that the idea is different from the act itself.”

Reference: Letter to Mersenne, 28 January 1641, AT III 295; CSMK 172.

This is extremely important for the broad-sense doctrine. The “idea” of willing is not a second mental object hovering over the volition; Descartes explicitly allows the idea not to be different from the act itself.

F. Broad-sense ideas: anything established by reasoning or perceived in any manner

Descartes extends the term “idea” to what is perceived in any manner whatsoever, including what is established by reasoning.

“I use the term ‘idea’ to apply to what is established by reasoning”

“as well as anything else that is perceived in any manner whatsoever.”

Reference: Third Replies, reply to Hobbes’s Ninth Objection, AT VII 185; CSM II 130.

“by an ‘idea’ I mean whatever is the form of a given perception.”

Reference: Third Replies, AT VII 188; CSM II 132.

This is even broader than the will/fear passage, since it includes what is established by reasoning, not only what is imagined or sensed.

G. Broad-sense ideas: correspondence with Mersenne

Descartes’s correspondence with Mersenne also confirms that “idea” can be used in a broad sense for whatever can be in thought or in the mind when conceiving.

“I use the word ‘idea’ to mean everything which can be in our thought, and I distinguish three kinds. ‘Some are adventitious’, such as the idea we commonly have of the sun; ‘others are constructed or made up’, in which class we can put the idea which the astronomers construct of the sun by their reasoning; and ‘others are innate, such as the idea of God, mind, body, triangle, and in general all those which represent true, immutable and eternal essences.“ (bold not in original)

Reference: Letter to Mersenne, 16 June 1641, AT III 383; CSMK 183.

“by ‘idea’ I do not just mean the images depicted in the imagination”

“I mean in general everything which is in our mind when we conceive something”

“no matter how we conceive it.”

Reference: Letter to Mersenne, July 1641, AT III 393; CSMK 185.

The July 1641 letter is one of the clearest broad-sense texts because it explicitly contrasts ideas with images depicted in the imagination and extends “idea” to what is in the mind when conceiving, regardless of manner.

H. Broad-sense ideas: “any object of thought”

The Fifth Replies contains one of Descartes’s most compact broad-sense formulations.

“you restrict the term ‘idea’ to images depicted in the imagination”

“whereas I extend it to cover any object of thought.”

Reference: Fifth Replies, AT VII 366–67; CSM II 253.

This formulation sharply opposes the restriction of ideas to corporeal images in the imagination. It supports the broad reading: idea = object of thought, not merely image in phantasia.

I. Material/objective ambiguity in “idea”

The Preface to the Reader introduces a different but related distinction: idea taken materially as an operation of the intellect versus idea taken objectively as the thing represented by that operation.

“‘Idea’ can be taken materially, as an operation of the intellect”

“Alternatively, it can be taken objectively, as the thing represented by that operation.”

Reference: Preface to the Reader, AT VII 8; CSM II 7.

This passage should not be collapsed into the strict/broad distinction. It is a different distinction: idea taken materially as an operation of thought versus idea taken objectively as the thing represented by that operation. But it is relevant because it explains why Descartes can move between idea-as-act and idea-as-represented-content without simply equivocating.

J. Best classification

Sense of “idea”	Core formula	Main references
Strict sense	Thought “as if the image of a thing”	Meditation III, AT VII 36–37 ; CSM II 25–26
Objective-content sense	Thing thought of insofar as it has objective being in the intellect	First Replies, AT VII 102–103; CSM II 74–75
Broad formal sense	Form of any given thought	Second Replies, AT VII 160–161; CSM II 113–14
Broad consciousness sense	Whatever is immediately perceived by the mind	Third Replies, AT VII 181; CSM II 127–128
Broad volitional sense	Ideas of what is in the will; idea not different from the act	Letter to Mersenne, 28 January 1641, AT III 295; CSMK 172
Broad conception sense	Everything in the mind when conceiving, however conceived	Letter to Mersenne, July 1641, AT III 393; CSMK 185
Broad object-of-thought sense	Any object of thought	Fifth Replies, AT VII 366–67; CSM II 253

K. Interpretive conclusion

The best interpretation is that Descartes has a privileged strict sense of idea as object-presenting or representational thought, but also a broader technical use in which “idea” can name the form, object, or immediate awareness involved in any thought, including volitions, fears, sensory perceptions, and items grasped by reasoning.

The strict sense is needed for objective reality and the causal argument. The broad sense is needed for Descartes’s ontology of thought and for his anti-Hobbesian insistence that ideas are not merely corporeal images.

Descartes uses idea in a broad sense to cover any mode of thought. Within that broad class, there are three importantly different cases.

Strict ideas contain objective reality.

These are broad-sense ideas, but they are also ideas in Descartes’s strict sense. They internally represent a representatum—a substance, mode, or true and immutable nature of a possible substance or mode—and therefore contain objective reality.

Examples include:

the idea of God,
the idea of body,
the idea of a triangle,
the idea of extension,
the idea of a determinate mode such as motion.

Composite broad-sense thoughts can contain objective reality, but only because they include a strict idea.

Many conscious acts are combinations of a strict idea with another mental act.

For example:

affirming that the triangle has three angles,
willing to obtain food,
fearing an approaching lion,
judging that the body is extended.

Here the affirmation, volition, or fear does not itself contribute objective reality. The objective reality belongs to the strict idea employed within the larger act.

Thus the composite broad thought contains objective reality, but only derivatively through one of its constituents.

Pure broad-sense acts need not contain any objective reality.

These include cases where there is no internal representatum.

On your DTOI account these include:

the mere sensation of cold (considered simply as a sensation),
pain merely felt,
generalized fear without an internally represented object,
bare acts of willing,
bare affirming or denying,
comparative notions such as largest or smallest,
second-order predicable roles such as genus and species,
the notion of nothing.

These are genuine conscious modes of thought with formal reality, but they contain no internally represented substance, mode, or true and immutable nature and therefore no objective reality.

The crucial point is that “broad-sense idea” and “objective reality” do not coincide. The broad class is larger than the class of OR-bearing thoughts.

A useful way to express the relationship is:

Broad-sense thought	Contains objective reality?	Why?
Strict idea	Yes	It contains an internal representatum.
Composite act (strict idea + affirmation, volition, fear, etc.)	Yes	The strict-idea constituent contains the objective reality.
Pure act (willing, affirming, sensation merely as sensation, comparison, classification, etc.)	No	No internal representatum is present.

This distinction is one of the central advantages of the Restriction Thesis. It preserves Descartes’s broad use of idea for all conscious thoughts while denying that every broad-sense idea contains objective reality. Instead, objective reality is restricted to those broad-sense thoughts that either are strict ideas or contain strict ideas as constituents.

Mapping of Examples in Descartes’s Philosophy: Ontological Status, *Ens Rationis* Alignment, Objective Reality, and Citations
(Context: DTOI analyses and the Restriction Thesis — objective reality is not a universal theory of ideas)
Example / Item	Ontological Status (Descartes’s Framework)	Ens Rationis Alignment	Objective Reality Level	Key Citations (AT / CSM)	DTOI / Restriction Thesis Notes
Ideas of privations / negations (e.g., cold as privation of heat; darkness; idea of nothing/non-being)	Privative or negative ideas; represent “what is nothing as if it were something”; arise from deficiency in the mind or lack of positive cause	Strongly aligned (classic limit case)	None; can be materially false if believed to exist	Third Meditation, AT VII 43–44 / CSM II 29–30	Core counterexamples where OR apparatus reaches its limit. Ideas represent non-things as things. Aligns with Restriction Thesis: OR non-existent for privative/non-representational contents.
Universals and abstract concepts considered generally (e.g., “man” in general; number-in-general; duration as universal)	Modi cogitandi (modes of thinking); intellectual abstractions or instruments of thought, not independent real things outside the mind	Yes (when considered abstractly/in general)	No independent ranked OR (OR apparatus falls silent per I.58)	Principles of Philosophy I.58–59, AT VIIIA 27–28 / CSM I 212–213	Directly supports DTOI baseline: universals as modi cogitandi without independent OR rank. Principles I.58 explicitly treats alia omnia, quae universalia vocamus as modes of thinking when considered in general.
Common notions / axioms and many eternal truths as principles (e.g., ex nihilo, nihil fit / “from nothing, nothing comes”; “nothing has no attributes”)	Positive principles of thought or intelligible truth-contents; innate or known by natural light; structure reasoning rather than represent ranked res	No (positive truths/principles, not entities or privations)	N/A or restricted; they are not ranked representata on the ontological hierarchy	Implicit/presupposed in causal reasoning (Third Meditation, AT VII 40–41 / CSM II 28); substance-attribute discussions (Principles); axioms in Second Replies, AT VII 145–146 / CSM II 104–105	Decisive in Restriction Thesis: these function as modi cogitandi or structural eternal truths where strict OR ranking does not apply. Ex nihilo, nihil fit is a foundational common notion used in causal arguments, not a being of reason.
True-and-immutable natures / geometrical essences (e.g., triangle with its determinate properties such as angles summing to 180°)	Determinate natures/essences with immutable properties; not invented by the finite mind; grounded in God’s creation of eternal truths	No (positive, non-invented content with genuine foundation)	Positive objective reality; represent ranked natures/essences	Fifth Meditation, AT VII 64–65 / CSM II 44–45	Belong in the OR-bearing class of ranked representational content (alongside substances and modes). Distinct from Table 2 modi cogitandi items. Ideas of them are not materially false.
Positive ideas of ranked res (e.g., idea of God; idea of finite substance; idea of a particular mode such as shape)	Represent real substances or modes that possess formal reality (or eminent containment)	No	Full ranked objective reality (infinite substance > finite substance > mode)	Third Meditation (causal adequacy principle), AT VII 40–42 / CSM II 28–29; Principles I.51–53, AT VIIIA 24–25 / CSM I 210–211	Core domain where Descartes’s OR framework succeeds as a theory of ranked representational content.
Real modes inhering in substances (e.g., particular shape or motion of a body) vs. denied Scholastic “real qualities”	Real modifications of substance (entia realia or modes); not mere conceptual items	No (real beings/modes, not ens rationis)	Inherit positive reality from the substance they modify	Principles I.53, I.61–62 (distinctions of reason vs. real), AT VIIIA 25, 29–30 / CSM I 210–211, 214	Descartes reduces what Scholastics treated as real qualities (accidents in the category of quality) to modes of extension or ideas/sensations in the mind. Menn’s footnote highlights that mere ens rationis cannot belong to categories of being such as quality.

Conclusions

The distinction between strict and broad ideas is not a peripheral terminological refinement but one of the organizing principles of Descartes’s theory of thought. Once this distinction is consistently maintained, numerous interpretive controversies assume a different shape. The central question is no longer whether every Cartesian idea is representational, but which conscious states actually contain an internal representatum and therefore possess objective reality.

According to my DTOI interpretation, only strict ideas satisfy that condition. They internally represent substances, attributes, true and immutable natures or essences, and modes, thereby supplying the objectively real representational content required for Descartes’s causal analysis of ideas. Broad ideas, however, encompass the much larger class of conscious mental modifications—including sensations, passions, volitions, and other acts—that need not contain any internally represented object. Their phenomenological content is formally real as a mode of thinking, but it is not thereby objectively real representational content.

This distinction also explains why sensations can be vivid, conscious, practically indispensable, and even clear and distinct when considered merely as sensations without becoming internally representational ideas.²

Their epistemic role is fundamentally different from that of strict ideas. Rather than presenting essences or natures through objective reality, they function primarily within the economy of the embodied mind, guiding action and preserving the human composite while remaining fully compatible with Descartes’s causal and metaphysical doctrines.

The wider consequence is methodological. Discussions of objective reality, material falsity, sensory representation, universals, impossible objects, and the causal adequacy principle all depend upon first identifying whether the mental state under consideration belongs to the strict or the broad sense of idea. Without that preliminary distinction, Descartes’s terminology appears inconsistent and his theory fragmented. With it, the various components of his theory of ideas become mutually reinforcing parts of a unified philosophical framework, one in which objective reality is properly restricted to internally representational ideas while the broader domain of conscious thought retains its own distinctive functions without being forced into an inappropriate representational model.

NOTES

1
See my “Table of Cartesian Commentators on the Status of Ideas.“

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2
See my posts:
“The Core DTOI Argument: Sensations Without Cartesian Objective Reality,”
“Why There Are No Successful Candidates For SQ-Sensations Objective Reality Content,”
“Do Cartesian Sensations Have Objective Reality?: Strict Ideas, Broad Ideas, And Material Falsity In Descartes’s Theory Of Ideas,” and
“How My DTOI Baseline Accounts For The Material Falsity Of Secondary Quality Sensations” to name a few.

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