Humber, James M. (1981). Recognizing clear and distinct perceptions. Philosophy and Phenomenological Research 41 (4):487-507.
(a) that Descartes does have distinguishing criterion for clear and distinct perceptions, and (b) that this criterion is Descartes' method of pro ducing such perceptions.
To be inattentive is to use words without being aware of what it is that those words signify. And to operate in this fashion is to fall victim to a "prejudice of youth":
. . .because we attach all our concepts to words for the expression of them by speech, and as we commit to memory our thought in connec tion with these words; and as we more easily recall to memory words than things . . . most men apply their attention to words rather than things, and this is the cause of their frequently giving their assent to terms which they do not understand, either because they believe that they formerly understood them, or because they think that those who in formed them correctly understood their signification (HR I, 252).
The error is obvious. When an inattentive person asserts that something is the case, e.g., 'I am a man,' he does so only because he has been "conditioned" or trained from youth to make these kinds of assertions. And since he has no clear perception or understanding of what it is that he is saying, he can have no assurance that what he states is true. Of course, what he says may be true; but as long as the speaker is inattentive, he runs the risk of "being deceived by the terms of ordinary language" (HR I, 155). And if what he says is true, "this comes about only by chance" (HR I, 176). In addition, the inattentive person cannot become attentive by utilizing scholastic definitions in order to clarify his assertions, for a person who proceeds in this way does nothing more than substitute one language (the scholastic language which he has been trained to use in the schools) for another (the language of everyday discourse). As such, he does not get at meaning, but continues to attend to words.
First, clear perception is not an activity of sensation or imagination, but an act of intellection, a "grasp" of meaning. And second, the objects of clear perception are not particular things which may be imaged or "pictured" in the mind. Rather, when mental images are the thoughts which serve as the focal point of the minds attention, the objects of clear perception are essences or forms which the understanding perceives as existing "in" its ideas. And because these forms are nonparticular, they can not be sensed or imagined, i.e., "pictured" in the mind. (E.g., the meaning of 'triangle' is not the sensed image of any particular triangle, nor the total set of triangular images able to be imagined, but rather a real form or essence intuitively perceived by the mind in each and every one of its particular triangle-ideas; (HR I, 180)).
(a) Descartes places all the objects of clear perception into one of three classes (HR I, 41; 238ff). First, there is God or Infinite Substance, and all of God's attributes. Second, there is finite substance, the two kinds of finite substance, and all the attributes and modes of finite substances.7 And finally, there are common notions or eternal truths. Common notions are not essences, forms, or mean ings, but principles of relation; and they do not exist in a hierarchy of generality. Descartes tells us that common notions can be discovered by the understanding either unaided, or when it is aware of the im ages of material things (HR I, 42). However, despite the fact that common notions may be found in the images of material things, they must not be considered as existing things or as modes of existing things, but rather as "eternal truths which have their seat in our minds" (HR I, 239). Included in this class are the laws of logic, the principle of the universality of causation, and "very many other pro positions the whole of which it would not be easy to enumerate" (HR I, 239).
Thus, if a person judges that his sensation of a pain is a mental-material act, he may be wrong because he is affirming that something is the case when his understanding does not actually see that it is so. And to avoid this error, one need only heed Descartes' injunction that "the knowledge of the understan ding should always precede the determination of will" (HR I, 176).
Although indistinctness only occurs when two or more natures are presented to the understanding as related, it is not the case that all perceptions of relationship produce indistinctness. When the mind attentively considers its thoughts, it clearly perceives essences, forms, or simple natures, and the necessary connections (common notions) between these natures:
It is. .. quite clear that this [intuitive] mental vision extends both to all those simple natures, and to the knowledge of the necessary connections between them . . . (HR I, 45).
First, in order to perceive clearly one must guard against the "prejudice" of attending to words rather than to things. To do this, one must only consider what it is that his words signify. Once this at titude is adopted, the person becomes aware of certain thoughts which "spring up" in his mind. And as attention is focused on these thoughts, immutable essences, forms, or natures become "present and apparent" to the percipient's understanding; that is to say, the person perceives clearly. Yet to perceive clearly is not necessarily to perceive distinctly, for there is another "prejudice of youth" which may cause one's clear perception to become distorted. Descartes believes that the will of man is capable of acting on its own, and that when it does so act it may judge that clearly perceived essences are related in ways not perceived by the intellect. Now compound percep tions created by the will's independent action may reflect reality. But because the understanding does not see why judgmentally created compounds must be related, there is absolutely no assurance that these perceptions do accord with reality. Consequently, one must be careful not to allow his perception to become distorted by potentially error-producing judgment. And to do this one need only heed Descartes' injunction "never to interconnect any objects unless [he or she] is aware that the conjunction of the one with the other is wholly necessary" (HR I, 45).