PART FOUR

ERRORS
TO WHICH HUMAN KNOWLEDGE
IS SUBJECT

CHAPTER 1

A summary of all the cognitions in which nature itself protects us from every error

1245. If truth and certainty had been committed to the care of human free will, they would have languished and in all probability soon been annihilated by human perversity. For this reason we saw that the first truths were entrusted by creative Providence to human nature, not to an individual human being. Human nature, essentially intelligent, sees the first truths essentially. Human beings cannot but see them, nor can they annihilate them. Just as they have no power to create anything, they have no power to destroy anything that has received existence from God [App., no. 11].

1246. Let us therefore briefly summarise all that nature does to ensure that human beings possess truth and are protected from error. We will thus confirm that genuine scepticism is impossible; that it is simply a lie told by an alienated human being to himself or others; and that in intelligent natures truth has a possession or even a dominion which cannot be taken away, although free human nature can sin against truth.

I. First, a human being naturally has the permanent vision of being in general. Being is the light of reason, the final reason of human reasoning; it always convinces while remaining unconquered itself.(154) This final reason is truth, so that all things are true in so far they share in it. The human being therefore possesses truth by nature.

II. The first principles of reason are the idea of being as applied (cf. vol. 2, 480 ss.) and, like the idea of being, are immune from error.(155)

These first truths are the sources of all human cognitions, but there are also truths of fact about which we cannot err. They are:

III. Human beings cannot be deceived about their own existence.(156)

IV. They cannot err about the direct consciousness of their principal modifications(157)

V. When our understanding receives solely what the senses give, they do not draw it into error [App., no. 12]. This witness of the senses is a part of the consciousness whose certainty was indicated in IV.

VI. Abstraction, which draws ideas from perceptions, that is, knowledge of the essences of things or, as the ancient writers called it, simple apprehension, is also immune from error.(158) As we have seen, these essences are the particular principles of the branches of knowledge, and correspond to the preconceptions or prol-yeiv of Epicurus.

Such then are the natural, unbreakable bonds by which truth is united and secured with our nature, a nature made for truth. However, we have reviewed only the limits placed on the temerity of human reason, limits within which reason's assaults against truth are defeated and repulsed. We must also consider the extent of error conceded to human beings within which they can harm themselves.

Notes

(154) St. Thomas teaches that the human being cannot in any way err about being. He says: Proprium obiectum intellectus est quod quid est (this means being, the essence of things): unde CIRCA HOC NON DECIPITUR INTELLECTUS ['The proper object of the intellect is that something is' (this means being, the essence of things). 'Hence the INTELLECT IS NOT DECEIVED IN THIS'] (Contra G., I, q. 58).

(155) St. Thomas says: Intellectus IN PRIMIS PRINCIPIIS NON ERRAT, sed in conclusionibus interdum, ad quas ex primis principiis ratiocinando procedit [The intellect DOES NOT ERR ABOUT FIRST PRINCIPLES, but errs in the conclusions it reaches when reasoning from first principles] (Contra G., I, q. 61).

(156) St. Thomas says: NULLUS ERRAVIT UNQUAM IN HOC QUOD NON PERCIPERE SE VIVERE [NOBODY HAS EVER ERRED BY NOT PERCEIVING THAT HE IS ALIVE] (De Verit., q. 10, art. 8).

(157) It was from this fact that Descartes' 'I think' (consciousness of thought) began, and evidence of this kind is the foundation of the whole Cartesian edifice. We have noted that although this foundation is solid, its solidity is due to the principles of reason; it cannot therefore be the first stone of the edifice of knowledge. Descartes' error is that he did not start to build from the foundations. It was the weak point which gave way against the assaults on Cartesian philosophy.

(158) This also was taught by St. Thomas (De Anima, bk. 3, less. 11): 'There is an action of the intellect by which it perceives what is indivisible' (that is, simple essences), 'for example, when it understands human nature, or the ox, or anything like this amongst non-composite objects. Such understanding is about things in which there is no falsehood both because non-composite things are neither true nor false, and because the intellect does not deceive itself about the being of things. But in those intelligible things which contain what is true and what is false, a kind of composition of understood things is present, as for instance, when a single thing is formed from many' (composite ideas are formed by the operation of synthesis). The non-composite things St. Thomas speaks of are pure ideas, devoid of judgment about real, subsistent things. There is nothing false or true in them because they are exemplars and truths of things. Truth and falsehood are present in things in the measure that the things correspond or not to their exemplar-ideas. If, therefore, we are not thinking of real things but only of ideas and possibilities of things, we never judge the correspondence of things to ideas. Truth and falsehood, and the possibility of error, are in this judgment.