How we are deceived

66. We are frequently wrong in our judgments regarding our sensations, affections, and appetites.

We can clearly know our sensations, affections, and appetites if we take care to use:

• our understanding, and
• what is affirmed by reason.

But it is difficult to always maintain such caution, especially regarding our senses.

This is because we have believed—from the very beginning of our lives—that all the things we perceive:

• exist outside of our thoughts, and
• are entirely similar to our sensations or ideas of them.

For example, we see a certain color.

We believe we were seeing a thing that:

• existed outside of us
• was similar to our idea of it

We make this judgment so many times.

• This makes it seem true to us

This is why some people remain so convinced by this false prejudice that they cannot even doubt it.

67. We are frequently deceived in our judgments regarding bodily pain itself.

The same bias exists in all our other sensations—even those of tickling and pain.

For although we did not believe that there were, outside of us in external objects, things resembling the tickling or pain that they caused us to feel, we nevertheless did not regard these sensations as ideas present only in our soul.

Instead, we believed they were located in our hands, our feet, and other parts of our body.

Yet there is no reason that obliges us to believe that the pain we feel—for example, in our foot—is something outside of our thought that actually resides in our foot; nor that the light we think we see in the Sun is in the Sun in the same way it is in us.

People have such a mistaken belief only because they place so much importance on the judgments they formed when they were children.

• They cannot let go of them in order to form more solid judgments.

68. How we must distinguish between error and truth.

The first step is to think that what we perceive as pain, color, and other feelings are really just in our minds.

Our errors begin when we think that our perceptions [color, pain, etc.] exist outside our minds.

For example, someone tells us they see color, or feel pain in their limbs.

He thinks that:

• that color or pain exists outside his mind
• he is not sure of that color or pain

When he does not examine his thoughts carefully, he might think that he knows that he perceives color or pain.

• This is because he thinks that the color he sees in the object resembles the sensation of color that he experiences within himself.

But nevertheless, if he reflects on what is represented by this color or pain, he will find that he has no knowledge of them.

69. We know magnitudes, shapes, etc. quite differently from colors, pains, etc.

The properties of bodies that we can perceive are:

• its size
• its shape
• its movement as change in place (Philosophers imagine other types of motion which means that they have not grasped the true nature of motion)
• the arrangement of its parts
• its time [duration]
• its quantity
• etc

Above all, we perceive these very differently from our other sensory perceptions like:

• the color of that same body
• pain, odor, taste, flavor, and everything attributed to the senses.

We are equally sure of the existence of a body that we see, through its color and shape.

Yet we grasp color and shape differently*.

70. We judge of sensible things in 2 ways:

1. In the correct way
2. In the wrong way

Sensations are confused thoughts.

Telling someone that we perceive colors in objects is the same as saying we perceive in these objects a feeling of color, the nature of which we do not know.

Yet there is a great difference in our judgments.

As long as we believe that there is something in the object which produces sensations within us, then we are not wrong.

We avoid error because we refrain from making hasty judgments about something that we do not truly understand.

But when we see blue in an object, we thnk that that blue is in the object and not in our minds.

This is because our senses bombard us with the other properties of the object such as its size, shape, number, etc.

Our senses make us believe that these properties exist in the object.

This persuades us that the blue color:

• exists within the object
• is the same as our idea of blue in our minds

But those properties do not really belong to the nature of the object.