The question of truth, the source of truth and how truth exists, appeared among the ancient Greeks along with the question of being. For this reason, just as the investigation of being is the primary tast of metaphysics, so is the question of truth. Truth designates that which is real, and was real and "that which always is and knows neither birth nor death." The Greeks called this sort of investigation a "gigantomachia": a struggle with giants, which means that it is a great and arduous undertaking. Over time these investigations took the form of a dispute, in which one side connected being and truth, while the other side separated them. The dispute was whether the ultimate source of truth is Being or Reason. Each response had not only theoretical consequences, but also practical consequences.
Today, with the perspective of time, we see that wherever man has divorced his cognition from being and made his own reason into the ultimate source and creator of truth, he inevitably lapses into nihilism. Vittorio Possenti discusses this in his very interesting book: "The Third Voyage: Nihilism and Metaphysics" (Rome 1998). This book compels us to reconsider the problem of being and cognition. It encourages us to join in the "third voyage", to redeem philosophy itself, the same direction taken in the 13th century by Thomas Aquinas. It is a way that has been rejected in modern and contemporary times. The important thing in the third voyage is to make really existing being our base and our guidepost in philosophy. The reason guided by the truth of things (recta ratio) then become genuinely rational , as does the whole of philosophy.
I would like to express my thanks for the invitation to this discussion of issue which are so important to philosophy and culture. In my talk I would like to discuss once again the problem of the source of truth. In searching for a solution to this problem, I will look at the proposition presented by Saint Thomas Aquinas in his metaphysics of real being.
In the search for the sources of truth, Thomas leads us to the "plateau" of existing beings. Beings are concrete and individual. Their individual acts of existence determines their individuality and concreteness. For this reason, individual things represent themseles and not merely some species or genus. The form (or essence) and the content (matter) of their existence is composed with existence in individual things.
On the "plateau", Thomas tells us to look at each concrete thing, as "inter duos intellectus constituta" - set between two intellects. One is the Intellect of the Creator, the other is the intellect of man. The Intellect of the Creator is the measurer (mensurans) in relation to things; and so it defines and establishes truth. The divine Intellect is not measured in itself (non mensuratum), nor is it determined by anything else. It is the source of the existence of each and every things and thus also the source of every truth. The Creator is He who define and assigns truth to things, somewhat like an artist to his works. Thus, each and every thing that is called to existence realizes in itself a particular truth that expresses the idea of the Creator.
In turn, the natural thing is both "measured and giving measure": it is defined with respect to its truth, but it also defines truth. This means that in things that an idea has been composed together with their existence, that each existing thing realizes an idea or thought within itself. The second intellect, the intellect of man, is merely that which is "measured", but does not itself provide the measure in relation to natural things. The human intellect is mensuratus non mensurans, and truth is found in the human intellect in a secondary or derivative way.
What is the truth, and where is the source of truth? Truth is the measure set by the Creator in things, and the knowing intellect is that which is measured by things. This applies in an analogous way to the human producer as a quasi-creator. Let us take note of Thomas' first discovery, which will be a key to understanding truth. Although Thomas, just like Aristotle, distinguished the order of the existence of being and the order of our cognition of being, he still emphasized that it is one and the same measure by which the individual thing has been measured by the Creator (or human artisan), and which gives measure to our intellect. The Creator called individual things to being according to particular individual ideas, not according to general ideas. For this reason, the truth of the being of a thing and the truth of our cognition of a thing is one and the same truth. Moreover, the order of the existence of things and the order of cognition are not mutually opposed, but they are inter-related. The truth that is composed with existence in things is that which causes cognition, hence cognition is the result of the truth that is within things (veritas sequitur esse rei).
Before arriving at this, Thomas first had to show that the world does not possess within itself its ultimate reason for existence. Since this is the case, the world and everything in it had to be called into existence by the Creator. Thomas also had to demonstrate that creation isthe act of the Creator's Intellect and Will, by which he calls things to existence. Furthermore, creation not only concerns that fact that things exist, but also what things are and their mode of existence. For this reason, the Provider of the existence of being, says Thomas - "is the cause of individual things both with respect to their form, and with respect to their matter (...), and He predetermines all individual things." Individual things were called to existence not according to any general ideas, as those who came before Thomas thought, but precisely in accordance with individual ideas. The calling of beings into existence takes place in and through the thought of the Creator. At the same time, this thought concerns the fact that the thing exists, what it is, and how it came into existence. The thought of the Creator permeates the whole of the being that comes into existence. The Creator "thinks things."Thomas devoted his most mature work - "De Ideis" - to this question. It is the work that earned him the title of Magister. In this work, he presents completely and in detail his understanding of ideas, and of the act whereby things are called into existence according to individual ideas. In this treatise he shows why both Plato and Aristotle did not accept ideas of individual things, but only of species and genera. One of the reasons why they did not accept individual ideas is that, according to Plato and Aristotle, ideas do not have the power of producing matter in lower being, but only of producing forms. Another reason is that ideas refer to that which "exists per se." This is why only species exist, as stable, eternal and identical in themselves, but individual things do not have being.
Thomas rejects this understanding of ideas as a priori and as implying a certain accepted theory of knowledge, and he points to the ideas of individual things, which are the causes of the existence of material and concrete things. This will follow primarily from Thomas' discovery of a new cause for the coming-to-be oif things, which is the efficient cause of the Creator.
Thomas will prove that the Creator "is the cause of individual beings both with respect to their form and with respect to their matter (...). For this reason it is necessary for us to accept the existence of ideas of individual things." For this reason, together with existence, all the measures of things are established according to the Idea or Thought of the Creator. There is nothing in a thing that is not intended by thought of the Creator and permeated by that thought.
The result is that the world of persons and things possesses complete intelligibility or knowability. On this account, the essences of things can be known, as well as their elements, such as matter and structure. Philosophers before Thomas Aquinas did not think this way. For them, matter by its very nature was unknowable, and so the entire material world was unknowable. All that could be known was the form and structure of things. Thomas, for the first time in the history of philosophy, could refer to the complete intellibility or rationality of the world. The world is intelligible because, "all effects, both primary and secondary, are derived from their prior definition (in the mind of the Creator). Thus we accept ideas not only of the first beings, but also of secondary beings, and by the same token, of substance and accidents, but of different accidents in different ways. Squareness and like accidents are of this kind."
Thomas' discovery of being as an individual idea completely determined or measured by the Intellect of the Creator, together with the bestowal of existence upon being, fills the hiatus that arose in Aristotle's theory of knowledge between the individual being and our cognition of this being. According to Aristotle, individuality does not constitute the "truth of things", since the basis of individuality was matter, and matter is unintelligible. For this reason individuality and matter do not enter into our cognition of things, but we may know only that which is general and immaterial.
The solution proposed by Thomas was revolutionary, both for how we understand being and how we regard the possibility of knowledge of being. Individual things arise in accordance with individual ideas, and as such they can be known. The act of existence is always the act of an individual being. The act of creation is precisely the continuation of individual beings in accordance with individual ideas. We may think of this act as "thinking things" or "thinking in things" and not thinking in generalities, as Plato, Aristotle and Saint Augustine supposed.
Thus, the truth of the individual thing cannot be basically different from our cognition of the thing. The truth, in which the human intellect participates, is not the result of cognition, which is what Aristotle believed, but on the contrary, cognition is the result of a truth - "cognitio est quidam veritatis effectus." This was a completely new and revolutationary approach to the question of truth, in comparison with the Aristotelean theory of cognition. The intellect, as Thomas says, "is measured by the truth of things." The truth of a thing is a concrete and individual thought or idea that is composed with the thing and called into existence together with the thing.
As a result, knowledge is something more than "adaequatio", it is above all a perfection of the one who knows. Knowledge becomes an important moment in the actualization of man's life as a person.
Thomas provides a very original description of truth. Truth is the measure of the thing - mensuratio rei. Thomas does not choose these terms by accident. He wants to leave behind the understanding of truth as a being,value or effect of cognition, and he wants to connect truth with the individual act of existence of things.
The word "mensura"(measure) or "mensuratio" (measurement, determination) leads us to conceive of truth as an individual "determination" of being. For this reason truth is determined not only by an act of the intellect in agreement with the form of a being (the specific form), as Aristotle thought, or the act of inspecting some ideal exemplar as Plato thought, but rather, truth is the measure of a thing read by the intellect, and by this reading the intellect becomes perfected, and thereby measured. The truth permeates the whole of being, both form and matter, both essence and the existence of essence. We see this by looking at how a thing is produce by art. The artist establishes not only the general ideas of things, but also selects the type of material, its color and size, etc. We may not that the artists make a selection of his material, he does not create it in the most basic sense. In this way in the thing produced (whether a painting, a chair, a table) the artist establishes the thing's measure (the truth) together with its entire endowment of content.
This fact shows the originality of Thomas' thought. When Thomas describes truth as the measure of the really existing thing, he in turn connects truth with the individual being. He who establishes measure in the thing is the Creator (God) or the producer (the human artisan) or the thing. This is what is called ontic truth, the truth "created" by an intellect. This entail a very important change in how we understand individual things. Individual things (and only individuals are real) bear within themselves and realize in their existence a thought (and thus, the truth). This is expressed in the fact that every truth is from the Creator, God, or in the case of produced things, from a human artisan. In trun, the truth that is composed into things, that which is called metaphysical truth, is that according to which the thing is measured and which measures the knowing intellect. The intellect that comes to know the truth does not establish the truth, since it is merely measured by the truth of things and comes into agreement with this truth. This is what is called logical truth.
We see, then, that in each being there is a truth (a thought) that permeates everything that the being is, everything from which it is made, by which it is, and the purpose for which it exists. For this reason, Thomas writes: Matter is caused by God (...). However, it is cannot be accepted that primary matter by itself had in God an idea distinct from the idea of form or of the composite being, since an idea in the strict sense refers to a thing, insofar as the thing can come into existence. Matter, however, cannot come into existence without form, nor the reverse. Therefore an idea in the strict sense cannot correspond only to form or only to matter, but one idea corresponds to a whole composite being, and this idea has the power to make the whole both with respect to form and with respect to matter.
We see then, that Thomas presents the problem of matter differently than Plato and Aristotle. For Plato, matter is the eternal place whether the Idea is reflected, and for Aristotle matter as such is something indefinite, the eternal and primordial stuff of the world. Thomas regards matter as originating from the Creator, and maatter appears when concrete beings are called into existence.
On this basis, we may say that every individual being is determined by the reasons of being which form the truths of things. There are the material, the formal, efficient and final reasons.
These reasons show that the genus of matter, its structure, quality and so forth are not accidental for any given being. It is not a mere accident that man has a body and that this body is such as it is. It is not an accident that a house is made of bricks rather than paper or flour, and that in any particular thing there is this and not some other quality and structure of matter. Just as the artist produces a work out of the right material and together with the material, which he did not call into existence but merely transforms, so the Creator calls the world into existence and particular things, and He creates together with them the matter that is right for them. Furthermore, matter is not a being by itself, but a cause of being, as is the opinion by those who hold that the world is completely subject to a process of evolution. Matter is subordinate to determinate beings when they are called into existence. Form is also ordered to the creative intellect, which is the intellect that measures or establishes the truth, and the same may be said about the end that is inscribed and grounded in things.
We see then, that the truth permeates and determines the whole of being. This is expressed in metaphysics as the principe that being and truth are interchangeable - "ens et verum convertuntur. All that is being is also thoroughly permeated by thought.
Along with Thomas' understanding of truth there appears a specific understanding of cognition. Cognition is not merely "adaequatio", but something more. Cognition is first and foremost a perfection of a personal being. This is because the truth is not the result of cognition, but rather, cognition is the result of the truth: cognitio est quidam veritatis effects. If there were no truth in things, there would not be any cognition.
Thomas also avoids any "reification of truth", which is treating truth like a being unto itself. He avoids also the instrumentalization of truth, that is, treating truth exclusively as a means of liberation, or the logicification of the truth, whereby truth would be treated merely as an effect of cognition. For this reason he specifically described truth as a measure, thanks to which the natural thing is measured and measuring (mensurata et mensurans). The truth that we know is the measure by which our intellect is measured and directed to the cognition of a being. The truth is then a consequence of the measure of a being's existence. As Thomas says: Veritas sequitur esse rei. Thus the truth that is given to man is not merely derived from cognition or thought, as is commonly accepted today, but together with things it is given to man. In this connection, Thomas writes:
Cognition takes place through an assimilation of the one cognizing to the thing that is cognized, such that this assimilation is the cause of cognition, as for example, when our vision knows a colour because it is disposed to this by the cognitive form of the colour.Cognition itself "is a certain effect of the truth (quidam veritatis effectus). Here Thomas notes:
The essence of truth is realized formally. This is what truth gives to being: the commensuration or accord of thing and intellect, and it is from this commensuration that our cognition of thing results, as was said. Thus, in this way the being of a thing precedes the concept of truth. Cognition is thus the result of a certain truth.
Thus, in order to resolve the doubt of those such as Descartes who sought the sources of truth in thought, or Kant who sought it in the structure of the intellect, Thomas writes that "being cannot be conceived without truth, because being cannot be conceived unless it corresponds to, or agrees with, the intellect."
Let us note that the truth that is grasped in the act of cognition (the effect of this accord) is accidental in relation to the truth of the thing. Thomas writes:
The truth that we speak about things in subordination to the human intellect is accidental, as it were, in relation to things, since if the human intellect did not, or could not, exist, the thing would still persist in its essence.
Moreover, let us note that there are no eternal truths existing for their own sake apart from things, conceived as the exemplars of things. All truths are rooted in beings as in their subjects. The truth is a thought, whether of the Creator or of a human maker, that is put in things at the moment when they are called into existence.
This formulation of the problem of truth is decisve in our formulation of the conception of realistic cognition. Cognition does not occur through an analysis of concepts, which would move from a generality to particulars. There is no valid inference from general ideas to a knowledge of individual things. Realistic cognition occurs through an intellectual inspection of things. In acts of affirming existence we grasp the individual thing in its individual idea, not in a general idea. We enrich the content of the individually existing thing by constantly reverting to the known thing, not by constantly explaining or elaborating what our cognition has already grasped from it.
Hence in realistic cognition, rather than going from the general to the particular, we express more clearly that which was grasped in a vague way. This is a process whereby the human person is perfected. The human person actualizes his own rationality through a familiarity with the truth of being.
The truth is connected with being and corresponds to being. Beings are individual, concrete and differentiated. For this reason, there are as many truths as there are beings. This view is different from that of Plato and Aristotle, who thought that there was a single general truth, whether of a species or genus, for many individuals. The truth of the individual being must correspond to our congitive grasp of it. Thus Thomas notes that the existence of a thing must enter into our conception of the essence of thing. The existence is always individual. Hence, there are "truths, which are as numerous in things as the existences of things."
Thus, all attempts to formulate a univocal definition of truth are futile, just as it is futile to try and formulate a univocal definition of being. Truth and being are analogical. Truth and being correspond ot hte mode of existence of the concrete individual being. The individuality of a being is expressed both in its individual act of existence and in its individual content that is determined by this act of existence. Otherwise the truth of cognition would be opposed to the truth of the things existence. If we present the matter in these terms, we can remove the conflict between truth as the measure of the existence of the individual thing, and truth as the measure of our knowledge of thing thing.
Thus, both being and truth must be understood analogically. At the beginning of the Disputed Questions on Truth,Thomas provides three groups of definitions.
In this way Thomas wants to turn attention to a very important matter, the analogical character or our understanding and definition of the truth.
In closing, I would like to show the consequences of this approach to the truth. I may mention the following as be particularly important: