Philosophical Works · Chapter
LXX explained
This chapter explains that we can judge sensible things in two ways: one that avoids error and one that leads to it.
What happens
This chapter explains that we can judge sensible things in two ways: one that avoids error and one that leads to it. It argues that perceiving colors in objects is equivalent to perceiving an unknown something that produces a sensation, and that error arises when we assume the sensation resembles the object's property, whereas we only clearly know properties like size, figure, and number.
Themes in this chapter
Skepticism and Certainty
The chapter contrasts judgments that avoid error (by acknowledging ignorance) with those that lead to error (by assuming resemblance), highlighting the skeptical stance toward sensory qualities.
Reason and Method
The discussion of how to judge correctly about sensible things exemplifies Descartes' method of avoiding rash judgments and relying on clear and distinct ideas.
Characters to notice
- Narrator
The narrator explains the two ways of judging sensible things and the nature of color perception.
Key passages
“That we may judge of sensible things in two ways, by the one of which we avoid error, by the other fall into it.”
There are two ways to judge sensory experiences: one that prevents mistakes and another that leads to them.
This opening sentence sets up the chapter's central distinction between correct and incorrect judgment about sensory qualities.
“It is thus manifest that to say we perceive colours in objects is in reality equivalent to saying we perceive something in objects and are yet ignorant of what it is, except as that which determines in us a certain highly vivid and clear sensation, which we call the sensation of colours.”
Claiming to see colors in objects actually means we perceive an unknown something that causes a vivid sensation we call color.
Descartes clarifies that color perception is not a direct grasp of a property but an awareness of an unknown cause producing a sensation.
“But when we think we perceive colours in objects, although we are in reality ignorant of what we then denominate colour, and are unable to conceive any resemblance between the colour we suppose to be in objects, and that of which we are conscious in sensation, yet because we do not observe this, or because there are in objects several properties, as size, figure, number, etc. , which, as we clearly know, exist, or may exist in them as they are perceived by our senses or conceived by our understanding, we easily glide into the error of holding that what is called colour in objects is something entirely resembling the colour we perceive, and thereafter of supposing that we have a clear perception of what is in no way perceived by us.”
We mistakenly assume that color in objects resembles our sensation, because we fail to notice our ignorance and because we correctly know other properties like size and shape, leading us to falsely believe we clearly perceive color.
This passage explains the psychological mechanism behind the error of attributing sensory qualities to objects as resembling our perceptions.