In his Repastinatio, Valla tries to shaken the foundations of the Aristotelian edifice. The term ‘‘repastinatio’’ not only means ‘‘re-ploughing’’ or ‘‘re-tilling’’ but also ‘‘cutting back’’ and ‘‘weeding out.’’ Valla wants to weed out all that he thinks is barren and infertile and to recultivate the ground by sprinkling it with the fertile waters of rhetoric and grammar. The term repastinatio is therefore an indication that Valla considers his program one of reform rather than one of destruction in spite of his often aggressive and polemical tone. The ten categories of Aristotle, for instance, are reduced to three (substance, quality, and action) rather than abolished entirely. At the back of his mind was the grammatical triad: noun, adjective, and verb, even though Valla realized that there was no simple one-to-one correspondence between nouns and substances or between verbs and actions. (A verb, for example, can also signify a quality.) From a grammatical point of view, words like ‘‘father,’’ ‘‘tall,’’ ‘‘at home,’’ and ‘‘grey-haired’’ all describe a quality of someone: hence, there is no need to keep separate categories for place, time, relation, etc. Valla went on to apply his analysis of things in terms of substances qualified by qualities and actions to the soul and God. The result of his reduction of the ten Aristotelian categories to his triad is a very lean ontology that has reminded scholars of William of Ockham’s nominalism. But while Ockham wants to keep the categories as long as we realize that they categorize terms rather than things, Valla wants to reduce them to substance, quality, and action because only this triad points to really existing aspects of things. Valla’s grammatical analysis has hardly anything in common with Ockham’s terminist-logical approach. On a similar note, Valla reduces the six transcendental terms - ‘‘being,’’ ‘‘thing,’’ ‘‘something,’’ ‘‘one,’’ ‘‘true,’’ and ‘‘good’’ - to ‘‘thing’’ (Latin res).
Another well-known example of his grammatical approach is his rejection of scholastic terms such as ‘‘entity’’ (entitas), ‘‘this-hood’’ (hecceitas), and ‘‘quidity’’ (quidditas) because they do not conform to the rules of word formation, rules that can be gleaned from a detailed study of classical texts. Related to this analysis is Valla’s repudiation of what he presents as the scholastic view of the distinction between abstract and concrete terms, that is, the view that abstract terms (‘‘whiteness,’’ ‘‘fatherhood’’) always refer to quality only, while concrete terms (‘‘white,’’ ‘‘father’’) refer to substance and quality. In a careful discussion ofthis distinction, taking into account the grammatical categories of case, number, and gender, Valla rejects the ontological commitments, which such a view seems to imply, and shows, on the basis of a host of examples drawn from classical Latin usage, that the abstract term often has the same meaning as its concrete counterpart (useful/utility, true/truth, honest/honesty). In other words, there is no need to posit abstract entities as referents of these terms; they refer to the concrete thing itself, that is, to the substance, its quality, or action (or a combination of these three components into which a thing can be analyzed). Hence, one of his main concerns throughout the first book is to determine to which category a word refers.
Valla further criticizes the Tree of Porphyry for putting not thing on top but substance, a notion that is barely intelligible: bare substance does not exist as a thing is always already a qualified substance. Moreover, it is difficult to place a human being, which consists of soul and body, in a Tree that divides substance into something corporeal and spiritual. In the rest of Book I of the Repastinatio, Valla criticizes distinctions such as matter and form and potency and act, using as weapons grammatical analysis and common sense.
In a long chapter in the same book, Valla takes up themes he had developed in an earlier work, On Pleasure (c. 1431). This was a dialogue between three interlocutors, a ‘‘Stoic,’’ an ‘‘Epicurean,’’ and a ‘‘Christian.’’ The result of this confrontation between pagan and Christian moral thought is a combination of Pauline fideism and Epicurean hedonism, in which the Christian concepts of charity and beatitude are identified with hedonist pleasure, and the philosopher’s concept of virtue is rejected. In taking ‘‘Epicureanism’’ (used in a rhetorical rather than a historical sense) as a stepping stone for the development of a Christian morality based on the concept of pleasure, Valla repudiated the traditional synthesis between Stoicism and Christianity, popular among scholastics and humanists alike. He found the Stoic notion of virtue as something to be aimed for its own sake abstract and unrealistic. He also criticized in a lengthy passage the Aristotelian notion of virtue as a mean between two vices as unduly dogmatic and inreflexible. A similar attitude informs his critique of Aristotelian natural philosophy. While his interests are clearly not those of a natural philosopher, he insists on common observation and experience as criteria for testing ideas and hypotheses. Hence, many of Aristotle’s contentions, so Valla argues, are not true to the facts. In arguing, for instance, for the existence of a fiery sphere below the moon, Aristotle had claimed that leaden missiles shot out by force melt in the air. Valla rejects this claim by appealing to common experience: we never see balls - whether leaden, iron, or stone shot out of a sling or cannon - heat up in the air. A similar argument was used later by Galileo.
The attack on Aristotelian-scholastic metaphysics, natural and moral philosophy is often couched in a highly polemical tone, but it carries a serious message. Valla is in effect sounding a serious warning against abstraction and theory: philosophers purport to analyze the world, but as soon as they start philosophizing they often leave that world far behind and play a game of their own making, with their own rules. This conviction recurs in books II and III of the Repastinatio when Valla turns to dialectics. This is the more constructive part of Valla’s attempt to reform what he considers to be the scholastic-Aristotelian paradigm. In these books he discusses propositions and their indicators of quality and quantity (‘‘every,’’ ‘‘any,’’ ‘‘not,’’ ‘‘no one,’’ etc.), the square of contraries, proof and argument, and various forms of argumentation. His approach is oratorical rather than logical. What counts is whether an argumentation works, which means whether it convinces one’s adversary or public. Formal validity is only one way of looking at argumentation, and a rather narrow way of looking at that. Rejecting the formal approach of the scholastics, Valla wants to base dialectic on real language by studying arguments in context, and what counts as context is much broader than the single sentence structure of the scholastic example. He thus rhetoricizes dialectic by stating that it is no more than a species of confirmation and refutation, and as such merely a part of one of the five parts of rhetoric: invention. Compared to rhetoric, dialectic is said to be an easy subject, which requires not much time to master, since it considers and uses the syllogism only in abstracto; its sole aim is to teach. The rhetorician, on the other hand, uses not only syllogisms, but also enthymeme (incomplete syllogism), epicheireme (a kind of extended reasoning), and example. The orator has to clothe everything in persuasive arguments, since his task is not only to teach but also to please and to move. This leads Valla to downplay the importance of the Aristotelian syllogism and to consider forms of argumentation that are not easily pressed into its straightjacket. Among these are captious forms of reasoning such as dilemma, paradox, and sorites (‘‘heap argument’’). Valla offers a highly interesting analysis of these types of arguments, which betrays his common sense approach and close attention to the common meaning of words and their context.
He regards the syllogism as an artificial type of reasoning, unfit to be employed by orators as it is does not reflect the natural way of speaking and arguing. What is for example the use of concluding that Socrates is an animal if one has already stated that every man is an animal and that Socrates is a man, thus that he is one of them? Valla rejects the additional moods of the first figure of the syllogism as wholly artificial. For the same reason the third figure should be utterly rejected. The first and second figure, however, can be accepted within limits, but Valla refuses to grant the first figure priority as Aristotle had done. Valla’s oratorical point of view leads him to reject the logical rules for transposing premises and converting terms as useless. Logicians used these rules in order to prove the validity of moods. When a syllogism can be reduced to one of the four of the first figure the syllogism is valid. But Valla thinks this technique absurd as it legitimizes syllogistic forms that lack any practical utility. Moreover, the traditional account unjustly ignores other syllogistic forms that might be accepted as valid, for example: God is in every place; Tartarus is a place; therefore God is in Tartarus. Here the ‘‘all’’ or ‘‘every’’ sign is added to the predicate in the major proposition. An all singular syllogism can also be valid: Homer is the greatest of poets; this is the greatest of poets; therefore this man is Homer. Valla gives many other examples of such deviant schemes, thus deliberately ignoring the criteria employed by Aristotle and his commentators. In his view, they unnecessarily restrict the number of possible valid figures.
Valla’s insistence on studying and assessing arguments in terms of persuasion and usefulness leads him to criticize not only the syllogism but also other less formal modes of argumentation. These arguments usually involve interrogation, leading to an unexpected or unwanted conclusion, or to an aporetic situation. Valla was one of the first to study and analyze types of arguments such as the heap argument (sorites) and dilemma. The heap argument is supposed to induce doubts about the possibility of determining precise limits especially to quantities. If I subtract one grain from a heap, is it still a heap? Of course. What if I subtract two grains? And so forth, until the heap consists of just one grain, which of course is an unacceptable conclusion. It seems impossible to determine the moment when the heap ceases to be a heap, and any determination of such a moment seems to be an ad hoc decision, for the difference between heap and no-longer-a-heap cannot be caused by the subtraction of just one single grain. Valla discusses a number of similar cases. He recognizes the fallacious nature of this sort of arguments, even though he does not clearly state what the solution would be or what a respondent should answer during such an interrogation.
Another type of argument is dilemma. Dilemmatic arguments had been widely studied in Antiquity. The basic structure is a disjunction of propositions, usually in the form of a double question in an interrogation, which sets a trap for the respondent, since whichever horn of the dilemma he chooses he seems to be caught up in a contradiction and will loose the debate (‘‘If he is modest, why should you accuse him who is a good man? Ifhe is bad, why should you accuse him who is unconcerned by such a charge?’’). It was also recognized that the respondent could often counter the dilemma by duplicating the original argument and ‘‘turn it back’’ (convertere) to the interrogator, using it as a kind of boomerang (‘‘if he is modest, you should accuse him because he will be concerned of such a charge; if he is bad, you should also accuse him because he is not a good man’’). Alternatively, he could escape the dilemma by questioning the disjunction and showing that there is a third possibility. There were many variations of this simple scheme. Based on Cicero, Quintilian, the Greek text of Aristotle’s Rhetoric, Aulus Gellius and George of Trebizond’s Rhetoric (c. 1433), Valla analyzes a series of such dilemma’s and the maneuver to counter a dilemma by converting it, called antistrephon in Greek and conversio in Latin. In all these cases he thinks, for various reasons, that the conversion is not a rebuttal at all but at best a correction of the initial argument (but a correction is not a refutation), at worst a simple repetition or illegitimate shift of that initial position. Valla’s reasonable suggestion then is that it was a product of the schools of rhetoricians, when the study of arguments could easily lead to an examination of their structure and strength without taking into account their wider context and the normal meaning of words. It had no real place in the oratorical practice.