24. If you reject any single sensation and fail to distinguish between the conclusion of opinion as to the appearance awaiting confirmation and that which is actually given by the sensation or feeling, or each intuitive apprehension of the mind, you will confound all other sensations as well with the same groundless opinion, so that you will reject every standard of judgment. And if among the mental images created by your opinion you affirm both that which awaits confirmation and that which does not, you will not escape error, since you will have preserved the whole cause of doubt in every judgment between what is right and what is wrong.

Alternate Translations: Bailey: If you reject any single sensation and fail to distinguish between the conclusion of opinion as to the appearance awaiting confirmation and that which is actually given by the sensation or feeling, or each intuitive apprehension of the mind, you will confound all other sensations as well with the same groundless opinion, so that you will reject every standard of judgment. And if among the mental images created by your opinion you affirm both that which awaits confirmation and that which does not, you will not escape error, since you will have preserved the whole cause of doubt in every judgment between what is right and what is wrong. Strodach: If you summarily rule out any single sensation and do not make a distinction between the element of belief that is superimposed on a percept that awaits verification and what is actually present in sensation or in the feelings or some precept of the mind itself, you will cast doubt on all other sensations by your unfounded interpretation and consequently abandon all the criteria of truth. On the other hand, in cases of interpreted data, if you accept as true those that need verification as well as those that do not, you will still be in error, since the whole question at issue in every judgment of what is true or not true will be left intact.

Letter to Herodotus: [We must also consider] the possibility of error and false judgments. These arise due to our supposing that a preconceived idea will be confirmed, or at any event will not be overturned, by additional evidence when we receive it. Falsehood and error arise when we form an opinion prematurely, without waiting for additional evidence to confirm or to contradict our conclusion before reaching it. [We must always recognize that] the representations we receive from images have been received by our intelligence like reflections from a mirror, whether those images are perceived in a dream or through any other conceptions of the mind or the senses. But [we cannot conclude that] these representations resemble the objects from which they came closely enough so that we can call them real and true unless we are examining objects that we perceive directly. Error arises when we receive impressions which our minds accept as a direct representation but which in fact are not. In such cases, due to considerations that are unique to ourselves, our minds mistakenly take these indirect perceptions and form conceptions which go beyond the reality of the actual object. Error results when our minds reach conclusions based on evidence that is not confirmed, or is contradictory, rather than based on evidence that we directly observe to be confirmed and uncontradicted.

We must carefully preserve these principles so that we will not reject the authority of our faculties when we perceive truth directly. We must also observe these principles so that we will not allow our minds to believe that what is false or what is speculative has been established with equal firmness with what is true, because this results in everything being thrown into confusion. If you simply reject any sensory experience which you believe to be incorrect, and you fail to reason and integrate those sensations which appear to conflict with those you know to be true, you will introduce a fundamental error into your logic that will lead you to be unable to separate true from false. Also, is a blunder to consider that some theory that is untested, and not proven to conform with reality, has the same status of truth as other knowledge which you know to be true, and which has been proven to be consistent with reality. This latter error is a blunder because you will then introduce doubt into your reasoning and lose the ability to distinguish the true from the false in everything.