{"id":37182,"date":"2026-02-20T16:04:32","date_gmt":"2026-02-20T16:04:32","guid":{"rendered":"https:\/\/drdavidcring.net\/descartes-ideas\/?p=37182"},"modified":"2026-04-24T16:42:42","modified_gmt":"2026-04-24T16:42:42","slug":"cartesian-commentators-on-the-objective-reality-contents-of-secondary-quality-sensations","status":"publish","type":"post","link":"https:\/\/drdavidcring.net\/descartes-ideas\/objective-reality\/cartesian-commentators-on-the-objective-reality-contents-of-secondary-quality-sensations\/","title":{"rendered":"A Hyperlinked Pictorial Table of Cartesian Commentators on the Objective Reality Contents of Secondary Quality Sensations"},"content":{"rendered":"\n
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NOTE:<\/span><\/strong> Several Cartesian commentators falsely claim that for Descartes sensations are not ideas. As a broad claim this is clearly false as supported by the quotations below. What is true is that sensations are not ideas in the strict sense<\/a> of being as if an image of a thing (tanquam rerum imagines<\/em>), although this is disputed by Lilli Alanen below.<\/p>\n\n\n\n

Paul Hoffman (“Descartes on Misrepresentation<\/a>,” Journal of the History of Philosophy<\/em> 34, no. 3 (July 1996): 357\u201381) even goes so far as to claim secondary quality sensations, such as that of coolness, are not even materially false by presenting a non-thing as if a thing! (see p. 358 where he asserts \u201cI will argue that, contrary to her [Margaret D. Wilson\u2019s] reading, Descartes does not believe that our ideas of light, colors, cold, heat and the like represent what is not a thing as if it were a thing<\/strong>. They are not materially false in that sense.\u201d bold not in original)<\/p>\n\n\n\n

We definitely know this is wrong since Descartes explicitly claims such sensations are his paradigm examples of materially false ideas in the Third Meditation precisely because they present a non-thing as if a thing [non rem tanquam rem repraesentant<\/em>], and most definitely in his Fourth Replies<\/em> to Arnauld:<\/p>\n\n\n\n

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“So I think that the only sense in which an idea can be said to be ‘materially false<\/strong>‘ is the one which I explained. Thus, whether cold is a positive thing or an absence does not affect the idea I have of it, which remains the same as it always was. It is this idea [a cold sensation]<\/strong> which, I claim, can provide subject-matter for error<\/strong> if it is in fact true that cold is an absence and does not have as much reality as heat; for if I consider the ideas of cold and heat just as I received them from my senses, I am unable to tell that one idea represents more reality to me than the other. (AT VII 232\u201333; CSM II 163; bold not in original)<\/p>\n<\/blockquote>\n\n\n\n

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\u201cFor I said that the falsity to be found in an idea is material falsity<\/strong>, while the falsity involved in a judgement can only be formal. . . . For it often happens in the case of obscure and confused ideas<\/strong>\u2014and the ideas of heat and cold fall into this category<\/em><\/strong>\u2014that an idea is referred to something other than that of which it is in fact the idea<\/strong><\/em>. Thus if cold is simply an absence, the idea of cold is not coldness itself as it exists objectively in the intellect, but something else, which I erroneously mistake for this absence, namely a sensation which in fact has no existence outside the intellect. . . . But as for the confused ideas of gods which are concocted by idolaters, I see no reason why they too<\/em> [along with cold sensations!] cannot be called materially false<\/strong>, in so far as they provide the idolaters with subject-matter for false judgements<\/strong>.” (AT VII 233; CSM II 163; bold and italic not in original)<\/p>\n<\/blockquote>\n\n\n\n

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“Confused ideas which are made up at will by the mind, such as the ideas of false gods, do not provide as much scope for error as the confused ideas arriving from the senses<\/strong>, such as the ideas of color and cold<\/em><\/strong> (if it is true, as I’ve said, that these ideas do not represent anything real<\/em><\/strong>).” (AT VII 234; CSM II 163; bold and italic not in original)<\/p>\n<\/blockquote>\n\n\n

Many of the quotations in this note below are translated by Jonathan<\/a> Bennett<\/a>\u00a0\"An<\/a> from his earlymoderntexts.com<\/a>. The AT and CSM references are supplied for ease of looking them up in those other sources.<\/p>\n

The main broad-sense texts for the wide sense of an idea<\/a> are these.<\/p>\n

First, the June 16, 1641 letter to Mersenne states the point in the bluntest possible way:<\/p>\n

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\u201cI use the word \u2018idea\u2019 to mean everything that can be in our thought. And I distinguish three kinds.\u201d (Letter to Mersenne<\/em>, 16 June 1641, AT III 383, CSMK III 183)<\/cite><\/p>\n<\/blockquote>\n

That text is already enough to show that Descartes is there using idea<\/em> far more widely than the strict Meditation III<\/em> sense of thoughts that are \u201cas it were images of things.\u201d Second, if sensations did not count as being \u2018in our thought\u2019 then a perceiver could not be aware of them. Since perceiver are aware of their sensations, they are in a perceiver\u2019s thoughts, so qualify as ideas<\/p>\n

Second, in the July 1641 correspondence with Mersenne, Descartes makes the same point even more explicitly, while also distancing himself from a merely imagistic conception of ideas:<\/p>\n

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\u201cI don\u2019t call the images painted in the physical imagination \u2018ideas\u2019; by \u2018idea\u2019 I mean in general everything that is in our mind when we conceive something, no matter how we conceive it.\u201d (Letter to Mersenne<\/em>, July 1641, AT III 393, CSMK III 185)<\/cite><\/p>\n<\/blockquote>\n

That passage is especially important because it directly opposes the narrow reading that would equate ideas only with imaginative images.<\/p>\n

Third, in the Second Replies<\/em>, Definition II, Descartes gives the official definition that underwrites the broader usage:<\/p>\n

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\u201cIdea<\/strong>. I understand this term to mean the form of any given thought, immediate perception of which makes me aware of the thought<\/strong>.\u201d (Second Replies<\/em>, AT VII 160\u201361, CSM II 113; bold not in original)<\/cite><\/p>\n<\/blockquote>\n

This definition is broader than the strict Meditation III<\/em> usage because it defines an idea through its role as the immediately perceived form of a thought, not as an image-like representational item only. One is immediately aware of one\u2019s own sensations, therefore that immediate perception of the sensation is an idea of the sensation.<\/p>\n

Fourth, in the Replies to the Third Objections<\/em> against Hobbes, Descartes explicitly includes volitions and fears among his ideas:<\/p>\n

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\u201cI am taking the word \u2018idea\u2019 to refer to whatever is immediately perceived by the mind. For example, when I want something, or am afraid of something, I simultaneously perceive that I want, or am afraid; and this is why I count volition and fear among my ideas.\u201d (Replies to the Third Objections<\/em>, AT VII 181, CSM II 127\u201328)<\/cite><\/p>\n<\/blockquote>\n

This is one of the strongest texts for the broad sense<\/a>, because willing and fearing are plainly not ideas in the strict image-like sense of Meditation III<\/em>, yet Descartes here counts them among his ideas.<\/p>\n

Fifth, in the Replies to the Fifth Objections<\/em> against Gassendi, Descartes explicitly contrasts his own broad use with Gassendi\u2019s narrow one:<\/p>\n

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\u201cyou restrict the term \u2018idea\u2019 to images depicted in the imagination, whereas I extend it to cover any object of thought<\/strong>.\u201d (Replies to the Fifth Objections<\/em>, AT VII 366, CSM II 253; bold not in original)<\/cite><\/p>\n<\/blockquote>\n

That line is probably the cleanest anti-narrowness text in the entire corpus. It shows that Descartes knew perfectly well that some readers wanted to confine idea<\/em> to imaginative images, and that he expressly rejected that restriction. A sensation is an object of thought so counts as an idea.<\/p>\n

So, if the question is where Descartes uses idea<\/em> in the wide or broad sense<\/a>, the core passages are:<\/p>\n