The Principle of Sufficient Reason is a powerful and controversial philosophical principle stipulating that everything must have a reason or cause. This simple demand for thoroughgoing intelligibility yields some of the boldest and most challenging theses in the history of metaphysics and epistemology. In this entry we begin with explaining the Principle, and then turn to the history of the debates around it. A section on recent discussions of the Principle will be added in the near future.

This book introduces the reader to Whitehead’s complex and often misunderstood metaphysics by showing that it deals with questions about the nature of causation originally raised by the philosophy of Leibniz. Whitehead’s philosophy is an attempt at rehabilitating Leibniz’s theory of monads by recasting it in terms of novel ontological categories.

Leibniz frequently argued that reasons are to be weighed against each other as in a pair of scales, as Professor Marcelo Dascal has shown in his article "The Balance of Reason." In this kind of weighing it is not necessary to reach demonstrative certainty – one need only judge whether the reasons weigh more on behalf of one or the other option However, a different kind of account about rational decision-making can be found in some of Leibniz's writings. In his (...) article "Was Leibniz's Deity an Akrates?" Professor Jaakko Hintikka has argued that Leibniz developed a new vectorial model for rational decisions which is better suited to complicated decisions, where values are complementary to each other. This model, related closely to his work in metaphysics and the philosophy of mind, is a heuristic device which helps in finding rational combinations - and in an ideal case an optimum - between plural inclinations to the good. I shall argue that Leibniz applies more or less implicitly both of these models in his practical rationality. In simple situations he applied the pair of scales model and in more complicated situations he applied the vectorial model. (shrink)

In this paper, the author will attempt to analyze some of the basic concepts in Leibniz’s Monadology from the perspective of the contemporary philosophy of the mind. The aim of the paper is to suggest that the traditional understanding of Leibniz as a pluralist or parallelist, though not completely untrue, is not always completely revealing and fruitful concerning its possible value for the philosophy of the mind. By analyzing some of the core concepts, the author will attempt to approach the (...) mind-body problem from a rather different angle, suggesting that the mind-body problem is to be regarded as an epistemological one, that is, it concerns how we know and speak of matter and nature. (shrink)

Leibniz often refers to the Principle of Sufficient Reason (PSR) as something like a first principle. In some texts, however, he attempts to give positive arguments in its favor. I examine two such arguments, and find them wanting. The first argument has two defects. First, it is question-begging; and second, when the question-begging step is excised, the principle one can in fact derive is highly counter-intuitive. The second argument is valid, but has the defect of only reaching a nearly trivial (...) conclusion. (shrink)

Not unlike many contemporary philosophers, Leibniz admitted the existence of temporary truths, true propositions that have not always been or will not always be true. In contrast with contemporary philosophers, though, Leibniz conceived of truth in terms of analytic containment: on his view, the truth of a predicative sentence consists in the analytic containment of the concept expressed by the predicate in the concept expressed by the subject. Given that analytic relations among concepts are eternal and unchanging, the problem arises (...) of explaining how Leibniz reconciled one commitment with the other: how can truth be temporary, if concept-containment is not? This paper presents a new approach to this problem, based on the idea that a concept can be consistent at one time and inconsistent at another. It is argued that, given a proper understanding of what it is for a concept to be consistent, this idea is not as problematic as it may seem at first, and is in fact implied by Leibniz’s general views about propositions, in conjunction with the thesis that some propositions are only temporarily true. (shrink)

This essay offers an account of the relationship between extended Leibnizian bodies and unextended Leibnizian monads, an account that shows why Leibniz was right to see intimate, explanatory connections between his studies in physics and his mature metaphysics. The first section sets the stage by introducing a case study from Leibniz's technical work on the strength of extended, rigid beams. The second section draws on that case study to introduce a model for understanding Leibniz's views on the relationship between derivative (...) and primitive forces. The third section draws on Leibniz's understanding of the relationship between derivative and primitive forces in order to shed light, in turn, on his understanding of the relationship between extended, material bodies and unextended, immaterial monads. The fourth section responds to a likely objection by arguing that Leibniz's monads may, in a perfectly reasonable sense, be spatially located. (shrink)

In the texts of the middle years (roughly, the 1680s and 90s), Leibniz appears to endorse two incompatible approaches to motion, one a realist approach, the other a phenomenalist approach. I argue that once we attend to certain nuances in his account we can see that in fact he has only one, coherent approach to motion during this period. I conclude by considering whether the view of motion I want to impute to Leibniz during his middle years ranks as a (...) kind of realism or rather as some kind of phenomenalism or idealism. (shrink)

Gottfried Wilhelm Leibniz (1646–1716) was one of the great thinkers of the seventeenth and eighteenth centuries and is known as the last “universal genius”. He made deep and important contributions to the fields of metaphysics, epistemology, logic, philosophy of religion, as well as mathematics, physics, geology, jurisprudence, and history. Even the eighteenth century French atheist and materialist Denis Diderot, whose views could not have stood in greater opposition to those of Leibniz, could not help being awed by his achievement, writing (...) in his Encyclopedia, “Perhaps never has a man read as much, studied as much, meditated more, and written more than Leibniz… What he has composed on the world, God, nature, and the soul is of the most sublime eloquence. If his ideas had been expressed with the flair of Plato, the philosopher of Leipzig would cede nothing to the philosopher of Athens.” (Vol. 9, p. 379) Indeed, Diderot's mood was almost despairing in a remark from another piece, which also has a great deal of truth in it: “When one compares the talents one has with those of a Leibniz, one is tempted to throw away one's books and go die quietly in the dark of some forgotten corner.” More than a century later, Gottlob Frege, who fortunately did not cast his books away in despair, expressed similar admiration, declaring that “in his writings, Leibniz threw out such a profusion of seeds of ideas that in this respect he is virtually in a class of his own.” (“Boole's logical Calculus and the Concept script” in Posthumous Writings , p. 9) The aim of this entry is primarily to introduce Leibniz's life and summarize and explicate his views in the realms of metaphysics, epistemology, philosophical theology, and natural philosophy. (shrink)

This article aims to make further progress in revising the standard account of Wolff’s philosophy as a popularisation and systematisation of Leibniz’s doctrines. It focuses on the topic of the communication among substances and the metaphysics of simples and activity underlying it. It is argued that Wolff does not accept the pre-established harmony in its orthodox Leibnizian version. The article explains Wolff’s departure from Leibniz’s PEH as stemming from his rejection of Leibniz’s construal of the activity of every simple as (...) representational power and of the metaphysics of unity and activity in which that construal is rooted. (shrink)

Leibniz speaks, in a variety of contexts, of there being two realms—a "kingdom of power or efficient causes" and "a kingdom of wisdom or final causes." This essay explores an often overlooked application of Leibniz's famous "two realms doctrine." The first part turns to Leibniz's work in optics for the roots of his view that nature can be seen as being governed by two complete sets of equipotent laws, with one set corresponding to the efficient causal order of the world, (...) and the other to its teleological order. The second part offers an account of how this picture of lawful over-determination is to be reconciled with Leibniz's mature metaphysics. The third addresses a line of objection proposed by David Hirschmann to the effect that Leibniz's doctrine undermines his stated commitment to an efficient, broadly mechanical account of the natural world. Finally, the fourth part suggests that Leibniz's thinking about the harmony of final and efficient causes in connection with corporeal nature may help to shed light on his understanding of the teleological unfolding of monads as well. (shrink)

I examine several alleged grounds of the principle of sufficient reason in Leibniz’s philosophy. These include the nature of a requisite and a sufficient condition, the nature of truth, and the nature of harmony. I argue that Leibniz does not ground the PSR in any of these ways. Instead, he is committed to a value-based grounds of the PSR: God creates the best possible world, and the fact that the PSR obtains in this world contributes to it being the best. (...) I conclude by considering some objections to this way of grounding the PSR. (shrink)

In this paper I argue against the received view that the anti‐nativist arguments of Book I of Locke's Essay conclusively challenge nativism. I begin by reconstructing the chief argument of Book I and its corollary arguments. I call attention to their dependence on (what I label) “the Awareness Principle”, viz., the view that there are no ideas in the mind of which the mind either isn't currently aware or hasn't been aware in the past. I then argue that the arguments' (...) dependence on this principle is question begging on two counts. Unless this principle is defended, Locke's arguments beg the question against Descartes and Leibniz because their nativism implies the denial of the Awareness Principle. And even when Locke defended the principle, his arguments remain question begging because they presuppose the empiricism they aim to prove. The disclosure of the question‐begging status of these arguments debunks a seemingly powerful way of attacking nativism. (shrink)

Resumen En el presente trabajo analizo el concepto de cuerpo en los escritos maduros de Leibniz. En el marco del debate contemporáneo acerca del estatus de la sustancia corpórea examino el entramado de las tres nociones sobre las que se construye la metafísica leibniziana de los cuerpos, a saber, la de materia prima, la de cuerpo orgánico y la de extensión. En cada caso evalúo el estatus ontológico que Leibniz les reconoce así como el papel que cumplen en su metafísica.In (...) this paper I examine the concept of body in Leibniz’s mature writings. In the context of the contemporary debate on the status of the corporeal substance, I analyze the relation between the three notions from which he builds his metaphysics of bodies, namely, the primary matter, the organic body, and the extension. For each case I evaluate their ontological status and the role they play in his metaphysics. (shrink)

A study is made of the general principles and theories pertaining to evolution, among which the definition, the evidences, the philosophical roots , the three models , and a further development of the last-mentioned model.

Leibniz's well-known thesis that the actual world is just one among many possible worlds relies on the claim that some possibles are incompossible , meaning that they cannot belong to the same world. Notwithstanding its central role in Leibniz's philosophy, commentators have disagreed about how to understand the compossibility relation. We examine several influential interpretations and demonstrate their shortcomings. We then sketch a new reading, the cosmological interpretation, and argue that it accommodates two key conditions that any successful interpretation must (...) satisfy. (shrink)

The author studies Leibniz’s views of vindicating God for the existence of evil in the world, as well as the idea of the best of all possible worlds, including the past and present criticism. Following Leibniz, he opted for the presentation of Herder’s philosophy of history as one of the most significant forms of philosophical optimism that influenced the first half of the 19th century, including contemporary debates on and critiques of the topic. He defines Herder’s concept as the philosophy (...) of historical progress, which also significantly influenced Slovak philosophy of the given period. The main goal of the article is to present Leibniz’s and Herder’s views as a starting point for the Slovak philosophy of optimism and historical progress of the 18th century and the first half of the 19th century. (shrink)

This article discusses Leibniz’s claim that every substance is endowed with the property of perception in connection with Platonism, rationalism and the problem of substance monism. It is argued that Leibniz’s ascription of perception to every substance relies on his Platonic conception of finite things as imitations of God, in whom there is ‘infinite perception’. Leibniz’s Platonism, however, goes beyond the notion of imitation, including also the emanative causal relation and the logical (i.e. definitional) priority of the absolute over the (...) limited. It is proposed that Leibniz’s endorsement of Platonism, in conjunction with some rationalist elements of his philosophy, implies a monistic conception of particulars as modifications of a single substance. Following some scholars and opposing others, the article offers evidence that Leibniz accepted this implication during the last years of his Paris period. However, it is further argued that it was precisely the idea of perception as a property of every substance that allowed Leibniz to find a way out of monism after that period. More specifically, the article defends the view that what made room for ontological pluralism within Leibniz’s rationalist and Platonic outlook was the idea that perception is the property which constitutes the very being of substances: substances are their perceptions. (shrink)

The article is a critical notice of Daniel Garber, Leibniz: Body, Substance, Monad. Garber presents a developmental reading of Leibniz's metaphysics that focuses on Leibniz's evolving analysis of body and force as the key to his account of substance. Garber claims that Leibniz shifts from an early theory of body to a theory of corporeal substance in his middle years, and only develops a theory of monads in his later writings—and that even then Leibniz looks not to abandon the scheme (...) of corporeal substances but to reconcile it with that of monads. The present article considers several challenges to Garber's interpretation, questioning, among other things, Garber's claims about development and Garber's account of Leibniz's primary arguments for the theory of monads. The article concludes that while crucial elements of the standard interpretation of Leibniz as an idealist can be defended against Garber's critique, the original traditional view that takes the theory of monads as the first and most fundamental principle of Leibniz's metaphysics is no longer sustainable. (shrink)

Leibniz believes that if there are corporeal substances, they have substantial forms, believes there are substantial forms, and believes there is a close connection between the first two claims. Why does he believe there is this close connection? This paper answers that question and draws out its bearing on the realism/idealism debate.