Introduction

The moderns have cut the Gordian knot with Alexander’s sword, and have introduced miracles into a natural thing, like gods in the theatre at the denouement of an opera.1 My aim was to explain naturally what they explain by perpetual miracles.2 1 G 3.346/NS 223....

Substance and Force

This chapter summarizes some of the important elements of Leibniz’s theory of substance, identifying how Leibniz conceived of his theory of substance as providing a foundation for a fully natural. Leibniz provides a naturalized account of causally active finite substances within the theoretical constraints described in Part I of the book. There are two aspects of substance that will take center stage: substances are active and representational. Force and activity derive ultimately from simple substances, and substances bear meaningful relations with their histories, their futures, and all other substances. This chapter argues that Leibniz aims to provide a clear and coherent metaphysic that involves created natures that have powers in their own right. The principal maneuver made by Leibniz is to revive Aristotelian substantial forms in a modified fashion, which, he thinks, will provide an intelligible account of the individual, causally active natures of things.

Moral Identity and the Appearance of the Self

This chapter considers Leibniz’s theory of moral identity, focusing on the aspects of moral identity that connect with Leibniz’s theory of consciousness and reflection. Rather than focusing on the conditions of identity over time, I intend to focus on what Leibniz calls the appearance of the self. What, exactly, is the content of the appearance and how does it occur? This chapter argues that the internal appearance of moral identity consists in the action of a substance on itself. The first section of this chapter distinguishes moral identity from other sorts of identity one will find in Leibniz’s writings. Then this chapter argues for the necessity of the appearance of moral identity to moral identity itself. Finally, this chapter provides an analysis of the content of the appearance that Leibniz describes as an appearance of moral identity.

Perception, Consciousness, and Continuity

This chapter looks at a vexed issue in Leibnizian interpretation––the question of Leibniz’s theory of consciousness. The phenomena of consciousness are apparently discontinuous, and, Leibniz argues, the failure to resolve these apparent discontinuities may lead one astray. I will show that the principle of continuity provides reasons to doubt that some of the main interpretations of Leibniz’s theory of consciousness are correct, and I will propose an interpretation that adheres more closely to this principle. Against those who argue that Leibniz’s theory of consciousness is a higher-order theory, this chapter argues that the standard presentation of such an interpretation violates the principle of continuity. An alternative threshold theory is presented and defended.

Living Mirrors

This chapter provides an analysis of perception, building on the theory of substance outlined in chapter 4. Leibniz offers both a top-down argument (from our experience to the properties of all simple substances) and a bottom-up argument (from a basic theory of substance to the interrelation of all substances) for the existence of expressive relations among substances. Each argument has some difficulties, and this chapter argues that the bottom-up argument is more promising. Section 2 outlines Leibniz’s general account of expression, and section 3 applies this account of expression to simple substances, arguing that there are two fundamental bases for expression in Leibniz: causation and relations of structure. Section 4 considers Leibniz’s arguments for universal expression and point of view. Finally, the differences between the two bases for expression in the simple substances are considered.

Nature and Natures

This chapter formulates Leibniz’s naturalizing claims: what it is for a theory to be a natural theory. Three things will be emphasized: (a) Leibniz’s focus on individual natures, (b) Leibniz’s appeal to “rules of the good and beautiful,” and (c) the representational nature of individual substances, building the “rules of the good and beautiful” into the individual, active natures. This allows for a robust natural theory that is informed by the good, and, hence, final causes will form a part of the overall natural theory. This chapter also considers how to define the scope of Leibniz’s natural theory. It is initially unclear how Leibniz can avoid either (1) extending his natural theory to include God’s actions (hence, natural philosophy extends to theology) or, on the other hand, (2) identifying the boundaries of his natural philosophy in an ad hoc way. This chapter argues that Leibniz does avoid these two landmines.

Self-Reflection, Perception, and Conceptual Thought

This chapter argues that the two-fold representation of the self provides a basis for conceptual thought. Some argue that perception and conception are, for Leibniz, radically divided, as they are in Kant’s accounts of intuition and understanding. If this is right, then there is an apparent threat to continuity and therefore to the naturalness of Leibniz’s philosophy of mind. However, this chapter argues that Leibniz is not necessarily committed to a gap here. First, conception is grounded in and arises from perception. Second, insofar as there are primitive concepts, animals could very well have those primitives as well, lacking only the ability to develop those ideas into conscious conceptual cognition. And so the difference would be the presence of a certain kind of ability, which rational beings have that non-rational beings do not have. This difference can be conceived as on a continuum.

Perceptual Distinctness and Mental Activity

Leibniz explains both activity and sensation in terms of the relative distinctness of perception. There is some worry that by applying distinctness in this way, Leibniz fails to articulate a univocal and coherent account of the distinctness of perception. This chapter argues that the systematic connection between activity and sensation is actually illuminated by Leibniz’s use of distinctness. This chapter argues that there is a way to resolve some interpretive difficulties by taking seriously Leibniz’s claims about mind–body parallelism and the mediation of perceptions via the body. To do so, we will need to modify Leibniz’s theory of expression even further in order to account for his theory of perceptual distinctness. By supplementing Leibniz’s account of expression with a mediation relation, the systematic nature of his thought is brought out more fully.

The Intelligibility of Nature

In response to Cartesian physics and occasionalist metaphysics, Leibniz consciously initiates a naturalizing project. This project takes shape, in particular, in Leibniz’s responses to Malebranche and other Cartesians. It is in this context that Leibniz develops his principle of continuity, which becomes a methodological principle for the remainder of Leibniz’s life. However, the commitment to continuity alone is not sufficient to dismiss occasionalism. This chapter considers what additional reasons Leibniz has for rejecting occasionalism as non-natural, which will demonstrate further naturalizing constraints on the theory. In support of the claim that naturalism is a thesis about intelligibility, we shall see that Leibniz requires an explanation in terms of the natures of finite substances involved. And this will be ultimately grounded in Leibniz’s appeal to the principle of sufficient reason and the principle of the best.

Conclusion

This distinction between what is natural and explicable and what is miraculous and inexplicable removes all the difficulties. To reject it would be to uphold something worse than occult qualities, and thereby to renounce philosophy and reason, giving refuge to ignorance and laziness by means of an irrational system....