ABSTRACTThis paper expounds and critically assesses G. W. Leibniz’s mature theory of the cohesion of material bodies. Leibniz’s later view of cohesion was forged in polemical engagement with the views of John Locke and the Dutch natural philosopher Nicolaas Hartsoeker and it is in Leibniz’s response to Locke in his New Essays on Human Understanding, and especially his correspondence with Hartsoeker, that the theory is revealed. After setting out Locke’s theory of solidity and cohesion, the paper examines Leibniz’s response to (...) Locke in the New Essays. It then proceeds to the mechanical theory of conspiring motions developed in the Hartsoeker correspondence. The final section of the paper poses three problems for Leibniz’s theory – explanatory, empirical, and conceptual. (shrink)

In this manuscript we initiate a systematic examination of the physical basis for the time concept in cosmology. We discuss and defend the idea that the physical basis of the time concept is necessarily related to physical processes which could conceivably take place among the material constituents available in the universe. As a consequence we motivate the idea that one cannot, in a well-defined manner, speak about time ‘before’ such physical processes were possible, and in particular, the idea that one (...) cannot speak about a time scale ‘before’ scale-setting physical processes were possible. It is common practice to link the concept of cosmic time with a space-time metric set up to describe the universe at large scales, and then define a cosmic time t as what is measured by a comoving standard clock. We want to examine, however, the physical basis for setting up a comoving reference frame and, in particular, what could be meant by a standard clock. For this purpose we introduce the concept of a `core' of a clock and we ask if such a core can - in principle - be found in the available physics contemplated in the various `stages' of the early universe. We find that a first problem arises above the quark-gluon phase transition where there might be no bound systems left, and the concept of a physical length scale to a certain extent disappears. A more serious problem appears above the electroweak phase transition believed to occur at $\sim 10^{-11}$ seconds. At this point the property of mass disappears and it becomes difficult to identify a physical basis for concepts like length scale, energy scale and temperature - which are all intimately linked to the concept of time in modern cosmology. This situation suggests that the concept of a time scale in `very early' universe cosmology lacks a physical basis or, at least, that the time scale will have to be based on speculative new physics. (shrink)

The aim of this paper is to critically assess the present state of Islamic philosophy in its main home, namely, Iran. However, since such a study requires some knowledge of the past developments of philosophical thought among Muslims, the paper briefly, though critically, deals with the emergence and subsequent phases of change in the views of Muslim philosophers from ninth century onward. In this historical survey I also touch upon the role played by other Muslim scholars such as theologians, mystics (...) and jurists, in shaping Islamic philosophy. The last section of the paper, deals, not in great details, with one or two possible scenarios for the future of Islamic philosophy. (shrink)

The debate concerning the ontological status of spacetime is standardly construed as a dilemma between substantivalism and relationalism. I argue that a trilemma is more appropriate, emergent spacetime theories being the third category. Traditional philosophical arguments do not distinguish between emergent spacetime and substantivalism. It is arguments from physics that suggest giving up substantivalism in favour of emergent spacetime theories. The remaining new dilemma is between emergent spacetime and relationalism. I provide a list of questions, which one should consider when (...) discussing emergent spacetime theories, and apply them to a quantum superfluid toy model of emergent spacetime. (shrink)

I consider the contrast between Leibniz's relational concept of spacetime and Einstein's special and general theories of relativity. I suggest that there are two interpretations of Leibniz's view, which I call L1 and L2. L1 amounts to saying that there is no real inertial structure to spacetime, whereas in general relativity the inertial structure is dynamical or real in Lande's sense ; i.e., it can be ‘kicked’ and ‘kicks back,’ causing gravitational effects. If there is no real inertial structure to (...) space-time then, as Weyl points out, the concept of the relative motive of several bodies has no more foundation than the concept of absolute motion for a single body. Thus, L1 seems to be untenable. L2 is a more sophisticated view which rejects the geometrical aspect of Newtonian space-time as a container for events, but accepts the existence of a real structure which determines the inertial properties of matter. (shrink)

How does Newton approach the challenge of mechanizing gravity and, more broadly, natural philosophy? By adopting the simple machine tradition’s mathematical approach to a system’s co-varying parameters of change, he retains natural philosophy’s traditional goal while specifying it in a novel way as the search for impressed forces. He accordingly understands the physical world as a divinely created machine possessing intrinsically mathematical features, and mathematical methods as capable of identifying its real features. The gravitational force’s physical cause remains an outstanding (...) problem, however, as evidenced by Newton’s onetime reference to active principles as the “genuine principles of the mechanical philosophy”. (shrink)

Although Newton carefully eschews questions about gravity’s causal basis in the published Principia, the original version of his masterwork’s third book contains some intriguing causal language. “These forces,” he writes, “arise from the universal nature of matter.” Such remarks seem to assert knowledge of gravity’s cause, even that matter is capable of robust and distant action. Some commentators defend that interpretation of the text—a text whose proper interpretation is important since Newton’s reasons for suppressing it strongly suggest that he continued (...) to endorse its ideas. This article argues that the surface appearance of Newton’s causal language is deceptive. What does New- ton intend with his causal language if not a full causal hypothesis? His remarks actually indicate a way of considering the force mathematically, something he contrasts to the structure of the force as it really is in nature. In explaining that, he identifies a significant disjunction between the physical force itself and mathematical ways of considering it, and the text’s significance lies in its view of the force’s structure and in the questions raised about the relationship between mathematical representations and the physical world. (shrink)

The ArgumentThe article explores the reasons for the rise to prominence of Newtonian natural theology in the period following the publication of thePrincipiain 1687, its continued importance throughout the eighteenth and first half of the nineteenth centuries, and possible explanations for its rapid decline in the second half of the nineteenth century. It argues that the career of Newtonian natural theology cannot be explained solely in terms of internal intellectual developments such as the theology of Newton's clerical admirers or the (...) impact of the work of Hume or of Charles Darwin. While such intellectual movements are undoubtedly of considerable importance in accounting for the rise and fall of Newtonian natural theology, they do not of themselves explain why British society was more receptive to particular bodies of thought in some periods rather than in others. Hence this article – in common with a number of recent studies – attempts to draw some connections between the growth of Newtonian natural theology and the character of Augustan society and politics; it also attempts to link the decline of this tradition with such nineteenth-century developments as the growing separation between church and state and the secularization of the universities and of scientific and intellectual life more generally. (shrink)

Debates about the ontological implications of the general theory of relativity have long oscillated between spacetime substantivalism and relationism. I evaluate such debates by claiming that we need a third option, which I refer to as “structural spacetime realism.” Such a tertium quid sides with the relationists in defending the relational nature of the spacetime structure, but joins the substantivalists in arguing that spacetime exists, at least in part, independently of particular physical objects and events, the degree of “independence” being (...) given by the extent to which geometrical laws exist “over and above” physical events exemplifying them. By showing that structural spacetime realism is the natural outcome of a semantic, model-theoretic approach to the nature of scientific theories, I conclude by arguing that the notion of partial isomorphic representation is the most plausible candidate to connect spacetime models with reality. (shrink)

I argue that there is natural relationist interpretation of Newtonian and relativistic non-quantum physics. Although relationist, this interpretation does not fall prey to the traditional objections based on the existence of inertial effects.

We discuss the concept of a cardinal number and its history, focussing on Cantor's work and its reception. J'ay fait icy peu pres comme Euclide, qui ne pouvant pas bien >faire< entendre absolument ce que c'est que raison prise dans le sens des Geometres, definit bien ce que c'est que memes raisons. (Leibniz) 1.

In this article it is shown that a careful analysis of Kant 's Gedanken von der wahren Schätzung der lebendigen Kräfte und Beurtheilung der Beweise leads to a conclusion that does not match the usually accepted interpretation of Kant 's reasoning in 1747, according to which the young Kant supposedly establishes a relationship between the tridimensionality of space and Newton's law of gravitation. Indeed, it is argued that this text does not yield a satisfactory explanation of space dimensionality, and actually (...) restricts itself to justifying the tridimensionality of extension. (shrink)

With the advent and growth of electronic communication, the word "cyberspace" has entered into everyday parlance. But what does this word signify? I begin by sketching an equivalence between physical space and cyberspace, showing that they share the concepts of place, distance, size and route in common. With this mutual framework in place, I go on to examine various theories—substantival, relational, Einsteinian and Kantian—concerning the nature of physical space. We see that, while cyberspace shares some of the properties of physical (...) space isolated by each of these theories, still it cannot be subsumed under any one theory. We also see that cyberspace exhibits several novel properties, projecting it far beyond the scope of any existing theory and setting it apart as an exciting new spatial medium. (shrink)

During the realist revival in the early years of this century, philosophers of various persuasions were concerned to investigate the ontology of truth. That is, whether or not they viewed truth as a correspondence, they were interested in the extent to which one needed to assume the existence of entities serving some role in accounting for the truth of sentences. Certain of these entities, such as the Sätze an sich of Bolzano, the Gedanken of Frege, or the propositions of Russell (...) and Moore, were conceived as the bearers of the properties of truth and falsehood. Some thinkers however, such as Russell, Wittgenstein in the Tractatus, and Husserl in the Logische Untersuchungen, argued that instead of, or in addition to, truth-bearers, one must assume the existence of certain entities in virtue of which sentences and/or propositions are true. Various names were used for these entities, notably 'fact', 'Sachverhalt', and 'state of affairs'. (1) In order not to prejudge the suitability of these words we shall initially employ a more neutral terminology, calling any entities which are candidates for this role truth-makers. (shrink)