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55Leibniz (1646-Leibniz (1646-

1716): Metaphysics1716): Metaphysics

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TAs office h.TAs office h.

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Introduction Introduction

A good introduction to Leibniz:A good introduction to Leibniz:

Jolley N. (2005). Jolley N. (2005). Leibniz. Leibniz. RoutledgeRoutledge

Leibniz’s Leibniz’s New EssaysNew Essays free at:free at:

http://http://www.earlymoderntexts.com/f_leibniz.htwww.earlymoderntexts.com/f_leibniz.htmlml

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The only published works of Leibniz attempts The only published works of Leibniz attempts to reconcile philosophy with Christian to reconcile philosophy with Christian doctrine. His most famous published book, doctrine. His most famous published book, TheodicyTheodicy, promised an explanation of the , promised an explanation of the existence of evil in a world created by a being existence of evil in a world created by a being who is perfectly good.who is perfectly good.

Leibniz was also a great logician.Leibniz was also a great logician.

He considered the theory of truth, not He considered the theory of truth, not religion, as the starting-point of philosophy.religion, as the starting-point of philosophy.

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Main (philosophical) worksMain (philosophical) works

Because of his diplomatic engagements Because of his diplomatic engagements he didn’t published a systematic work he didn’t published a systematic work like other contemporary philosophers like other contemporary philosophers (e.g.: Descartes, Locke, …). He published (e.g.: Descartes, Locke, …). He published only one book. Other books have been only one book. Other books have been published after his dead.published after his dead.

Lot of letters/correspondences with major Lot of letters/correspondences with major philosophers (Arnauld, Malbranche,…)philosophers (Arnauld, Malbranche,…)

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BOOKS:BOOKS:

DiscourseDiscourse on Metaphysicson Metaphysics (composed in 1686). (composed in 1686). Each substance, is like a whole world and Each substance, is like a whole world and like a mirror of God.like a mirror of God.

New Essays on Human UnderstandingNew Essays on Human Understanding(composed in 1703-5). (composed in 1703-5). He didn’t publish it because Locke died in He didn’t publish it because Locke died in the autumn of 1704. Locke’s essays have the autumn of 1704. Locke’s essays have been published in 1690. This is known to been published in 1690. This is known to be one of the best debate between a be one of the best debate between a rationalist and empiricist conception.rationalist and empiricist conception.

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Essay on TheodicityEssay on Theodicity (= the justice of (= the justice of God. published in 1710). God. published in 1710). The only book he published. Defence of the The only book he published. Defence of the justice of God who created the best of the justice of God who created the best of the possible worlds. It is an attempt to possible worlds. It is an attempt to reconcile the existence of evil in the world reconcile the existence of evil in the world with God’s benevolent nature.with God’s benevolent nature.

MonadologyMonadology (composed 1714). (composed 1714). Monads are spiritual substances created by Monads are spiritual substances created by God. They are the basic building block of God. They are the basic building block of nature.nature.

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God’s Will and IntellectGod’s Will and Intellect Main ThesisMain Thesis

God’s mind consists in a will and intellect, God’s mind consists in a will and intellect, like the human mind. like the human mind.

VsVs. Descartes. Descartes

Descartes argued that it would be a Descartes argued that it would be a contradiction to suppose that God’s will is contradiction to suppose that God’s will is determined to act in one way or another (cf. determined to act in one way or another (cf. Reply to Sixth Objections, Objection 6). Reply to Sixth Objections, Objection 6).

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DescartesDescartes: God doesn’t act out of a prior : God doesn’t act out of a prior conception of what is good or bad.conception of what is good or bad.

God’s God’s acts of will determineacts of will determine what is what is good or bad.good or bad.

This allowed Descartes to explain God’s This allowed Descartes to explain God’s freedom in terms of the indifference of freedom in terms of the indifference of God’s will.God’s will.

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Leibniz considered this view to be dangerous, Leibniz considered this view to be dangerous, in that it threatened to in that it threatened to make values relativemake values relative. .

If what is good or bad depends on God’s If what is good or bad depends on God’s arbitrary whish, what we now call bad could arbitrary whish, what we now call bad could just as well be good if God decided so.just as well be good if God decided so.

Leibniz proposed instead that God’s intellect Leibniz proposed instead that God’s intellect determines his will. determines his will.

God does that which s/he considers to be the God does that which s/he considers to be the best.best.

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God’s acts are timeless God’s acts are timeless (i.e. they don’t take (i.e. they don’t take place in time)place in time)

One of Leibniz’s most basic general One of Leibniz’s most basic general metaphysical principles, the “metaphysical principles, the “principle of principle of sufficient reasonsufficient reason”, is based on this ”, is based on this supposition. supposition.

Anything that exists is due to the activity of Anything that exists is due to the activity of God, and God always acts for the reason that it God, and God always acts for the reason that it is the best.is the best.

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Principle of Sufficient ReasonPrinciple of Sufficient Reason

For anything that exists, there is a For anything that exists, there is a reason sufficient to determine God’s reason sufficient to determine God’s will to bring it about, i.e., the reason will to bring it about, i.e., the reason that its existence would be for the that its existence would be for the best.best.

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Ontological EconomyOntological Economy

God’s actions follow a principle of economy. God’s actions follow a principle of economy. God acts according to the most economical God acts according to the most economical means to bring about the most abundant means to bring about the most abundant ends. ends.

Analogy: An architect, for example, will use Analogy: An architect, for example, will use his location and the funds set aside for a his location and the funds set aside for a building in the most advantageous manner, building in the most advantageous manner, allowing nothing improper or lacking in the allowing nothing improper or lacking in the beauty of which it is capable. beauty of which it is capable.

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God’s economy is carried out through the God’s economy is carried out through the use of general rules governing creation. use of general rules governing creation.

Some of these rules are discoverable by us Some of these rules are discoverable by us humans, and we call them laws of nature. humans, and we call them laws of nature. Others are hidden. These are in play when Others are hidden. These are in play when there is a miracle which violates a law of there is a miracle which violates a law of nature. nature.

Miracles are not irregular events but Miracles are not irregular events but conform to more general regularities.conform to more general regularities.

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The Metaphysics of The Metaphysics of SubstancesSubstances

Critique of DescartesCritique of Descartes

A substance must be a genuine unity. A substance must be a genuine unity.

In Descartes the universe is composed of In Descartes the universe is composed of two created substances: two created substances:

(i) (i) mindmind whose essence is to think, whose essence is to think, and and

(ii)(ii) body body whose essence is to be whose essence is to be extended (three-extended (three- dimensional) dimensional)

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Body as it is conceived by Descartes Body as it is conceived by Descartes doesn’t fit the bill of being a doesn’t fit the bill of being a substance. substance.

Descartes’ main problem is that he Descartes’ main problem is that he neglected the Aristotelian tradition neglected the Aristotelian tradition ……

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Aristotle’s two tests for being a Aristotle’s two tests for being a substancesubstance

1. The linguistic test1. The linguistic test

Substances are the ultimate subject of Substances are the ultimate subject of predication. Socrates passes the test since predication. Socrates passes the test since we can predicate many things of him, while we can predicate many things of him, while Socrates can be predicated to nothing.Socrates can be predicated to nothing.

The name “Socrates” can appear only in The name “Socrates” can appear only in subject position (cf. singular subject position (cf. singular vs.vs. general general terms). terms).

A substance must be something designated A substance must be something designated by a singular term.by a singular term.

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2. The metaphysics test2. The metaphysics test

Substances are substrata of things. The most Substances are substrata of things. The most distinctive mark of a substance is what distinctive mark of a substance is what remains numerically the same (cf. Aristotle’s remains numerically the same (cf. Aristotle’s essentialism). essentialism).

Numerical identity Numerical identity vsvs. Qualitative identity. Qualitative identity

Socrates the baby is 2 feet tall while Socrates the baby is 2 feet tall while Socrates the adult is 6 feet tall, yet Socrates Socrates the adult is 6 feet tall, yet Socrates is one and the same individual.is one and the same individual.

Socrates numerical identity cannot Socrates numerical identity cannot correspond to his body (correspond to his body (resres extensaextensa).).

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Leibniz’s argument against Descartes’ Leibniz’s argument against Descartes’ doctrine of extended substances (doctrine of extended substances (res res extensaextensa))

1. 1. No aggregate is an ultimate subject of No aggregate is an ultimate subject of predicationpredication2. 2. An entity whose essence is extension is an An entity whose essence is extension is an

aggregateaggregate3.3. Therefore, no entity whose essence is Therefore, no entity whose essence is extension is extension is an ultimate subject of an ultimate subject of predication.predication.

Since being an ultimate subject of predication is Since being an ultimate subject of predication is a necessary condition for being a substance, no a necessary condition for being a substance, no entity whose essence is extension is, entity whose essence is extension is, pace pace Descartes, a substance.Descartes, a substance.

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Any Cartesian body is composed of other Any Cartesian body is composed of other bodiesbodies

Nowhere in Descartes’ theory of the physical Nowhere in Descartes’ theory of the physical world we come to entities which are not world we come to entities which are not themselves aggregates.themselves aggregates.

Leibniz introduces a stipulative definition of Leibniz introduces a stipulative definition of “substance”:“substance”:

““substance” =substance” =df.df. “That which has a true “That which has a true unity”unity”

Therefore, any entity whose essence is extension Therefore, any entity whose essence is extension is not a substance since it lacks genuine unity.is not a substance since it lacks genuine unity.

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The Logicist StrategyThe Logicist Strategy

All true predication has some foundation in All true predication has some foundation in the nature of things.the nature of things.

When the predicate is not expressly included When the predicate is not expressly included in the subject, it must be virtually included in in the subject, it must be virtually included in it (it (‘in esse’: ‘in esse’: the predicate is in the subjectthe predicate is in the subject))..

The subject term must always involve that of The subject term must always involve that of the predicate. So one who perfectly the predicate. So one who perfectly understands the subject notion would also see understands the subject notion would also see that the predicate belongs to it.that the predicate belongs to it.

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TheThe concept-containment theory of concept-containment theory of truthtruth

In all true affirmative propositions, necessary or In all true affirmative propositions, necessary or contingent, universal or singular, the notion of the contingent, universal or singular, the notion of the predicate is always in some way included in that of predicate is always in some way included in that of a subject …-- or I don’t know what truth is. (Leibniz, a subject …-- or I don’t know what truth is. (Leibniz, Philosophical Texts, Philosophical Texts, Oxford UP 1998: 11-2) Oxford UP 1998: 11-2)

Proper name: it’s not an arbitrary simple Proper name: it’s not an arbitrary simple tag. It expresses a concept like a general tag. It expresses a concept like a general term (e.g. “lemon”, “gold”).term (e.g. “lemon”, “gold”).

Hence: “Cesar crossed the Rubicon” is true Hence: “Cesar crossed the Rubicon” is true because the predicate “crossed the because the predicate “crossed the Rubicon” is contained in the subject concept Rubicon” is contained in the subject concept expressed by the name “Cesar”.expressed by the name “Cesar”.

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Individual substances have complete Individual substances have complete conceptsconcepts..

If one were to know the complete concept of If one were to know the complete concept of Alexander, one would Alexander, one would ipso factoipso facto also know also know everything there was to be known about the everything there was to be known about the universe.universe.

All relational truths about individual substances All relational truths about individual substances can be deduced from non-relational truths can be deduced from non-relational truths about those substances. (e.g.: “Mary is Tim’s about those substances. (e.g.: “Mary is Tim’s sister”; being Tim’s sister is contained in Mary’s sister”; being Tim’s sister is contained in Mary’s substance …)substance …)

Every substance expresses the universe. But Every substance expresses the universe. But only God can recognize the whole concept.only God can recognize the whole concept.

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CausalityCausality The critique of the influx modelThe critique of the influx model

Influx modelInflux modelCausal interaction about substances in the Causal interaction about substances in the world must be understood as involving a world must be understood as involving a process of process of contagioncontagion..

When a substance A causes a change in When a substance A causes a change in substance B, A infects B with one of it substance B, A infects B with one of it properties (i.e. by an instance of a property). properties (i.e. by an instance of a property). E.g.: when the kettle boils the gas infects the E.g.: when the kettle boils the gas infects the water within the kettle.water within the kettle.

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The influx model of causality is (for Leibniz) The influx model of causality is (for Leibniz) incoherent for it rests on the metaphysical incoherent for it rests on the metaphysical fiction that accidents can become detached fiction that accidents can become detached from their own substance and move to other from their own substance and move to other substances.substances.

There is no causal interaction between There is no causal interaction between substances. Leibniz claims that monads (the substances. Leibniz claims that monads (the ultimate substances) have no windows. Pre-ultimate substances) have no windows. Pre-established harmony.established harmony.

Causality of creatures is modeled on Divine Causality of creatures is modeled on Divine creation. creation.

Created substances are mirrors of God.Created substances are mirrors of God.

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OntologyOntology CreatedCreated substancessubstances::

1. 1. they are genuine unitiesthey are genuine unities2.2. they are genuinely active and causally self-they are genuinely active and causally self-sufficientsufficient3.3. they express the entire universe (and thus they express the entire universe (and thus reflect reflect the divine perfection of omniscience)the divine perfection of omniscience)

In all these ways substances are mirrors of God In all these ways substances are mirrors of God (Cf. (Cf. GenesisGenesis: God made man in his own image).: God made man in his own image).

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Leibniz abandons the Aristotelian ontology Leibniz abandons the Aristotelian ontology of corporeal substances.of corporeal substances.

The doctrine of monads is a form of idealism.The doctrine of monads is a form of idealism.

Appearance Appearance vs. vs. RealityReality

Emphasis (already in Descartes) on the fact Emphasis (already in Descartes) on the fact that appearances are misleading. that appearances are misleading.

The physical world is, strictly speaking, The physical world is, strictly speaking, deprived of sensory qualities (e.g. colors, deprived of sensory qualities (e.g. colors, odors and taste…)odors and taste…)

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MonadsMonads Monad Monad (from the Greek meaning unity) = a (from the Greek meaning unity) = a

simple, immaterial, soul like, substance simple, immaterial, soul like, substance endowed with perception and appetition.endowed with perception and appetition.

Appetition Appetition = the endeavor or striving in a = the endeavor or striving in a monad by virtue of which it passes from one monad by virtue of which it passes from one perceptual state to its successor. Appetition perceptual state to its successor. Appetition explains monad dynamicity.explains monad dynamicity.

So simple substances/monads can be sources So simple substances/monads can be sources of activity.of activity.

AtomismAtomism: Monads are the true atoms of : Monads are the true atoms of nature.nature.

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Since nothing purely material can be Since nothing purely material can be indivisible, monads indivisible, monads cannot be like atoms cannot be like atoms traditionally conceivedtraditionally conceived. .

Monads Monads quaqua simple are simple are without partswithout parts. Thus . Thus they cannot be corporeal. They must be they cannot be corporeal. They must be immaterial.immaterial.

Monads are Monads are indestructibleindestructible, for destruction , for destruction consists in decomposition which is a consists in decomposition which is a dissolution of a thing into its composing parts dissolution of a thing into its composing parts (see unity of substance).(see unity of substance).

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Monads can begin (and end) only by a Monads can begin (and end) only by a miraculous act of creation (or annihilation).miraculous act of creation (or annihilation).

If monads are simple, immaterial and If monads are simple, immaterial and indestructible, then the building block of the indestructible, then the building block of the universe share certain properties with God universe share certain properties with God (they are the mirror of God).(they are the mirror of God).

The building blocks of the universe are all The building blocks of the universe are all mental or soul like entities. They are spiritual mental or soul like entities. They are spiritual atoms.atoms.

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Monads are Monads are windowlesswindowless: So neither : So neither substance nor accident can come into a substance nor accident can come into a monad from outside.monad from outside.

All monads express (perceive) the entire All monads express (perceive) the entire universe. Yet no two monads are exactly alike. universe. Yet no two monads are exactly alike. They have different They have different points of viewpoints of view..

Differences in points of viewDifferences in points of view: to be : to be analyzed in term of the distribution of clarity analyzed in term of the distribution of clarity and distinctness over their perceptual states. and distinctness over their perceptual states.

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Identity of Indiscernible: Identity of Indiscernible: Leibniz LawLeibniz Law

The notion of point of view allows Leibniz to The notion of point of view allows Leibniz to accept the principle of the accept the principle of the Identity of Identity of Indiscernibles Indiscernibles (sometimes also known as (sometimes also known as Leibniz law).Leibniz law).

If, for every property If, for every property FF, object , object xx has has FF if and if and only if object only if object yy has has FF, then , then xx is identical to is identical to yy. .

F(Fx F(Fx Fy) Fy) x=y x=y

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Converse of the Principle: the Converse of the Principle: the Indiscernibility of IdenticalsIndiscernibility of Identicals

If If xx is the same as is the same as yy, then , then xx and and yy have all have all the properties/qualities in common.the properties/qualities in common.

x=y x=y F(Fx F(Fx Fy) Fy)

Sometimes the conjunction of both Sometimes the conjunction of both principles, rather than the Principle by principles, rather than the Principle by itself, is known as Leibniz's Law. itself, is known as Leibniz's Law.

x = y x = y Fx Fx Fy Fy

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The hierarchyThe hierarchy of monads. of monads.

1. 1. God is on top by virtue of possessing God is on top by virtue of possessing perceptions perceptions that are clear and distinct.that are clear and distinct.

2.2. Human minds are lower. They are Human minds are lower. They are high quality high quality monads by virtue of (i) monads by virtue of (i) possessing reason allowing possessing reason allowing them to them to entertain eternal truth of logic and entertain eternal truth of logic and mathematics and (ii) self-consciousness: mathematics and (ii) self-consciousness: the ability the ability to say “I”.to say “I”.

3. 3. At the bottom we have bare monads. At the bottom we have bare monads. They have They have perceptual states but they perceptual states but they are extremely confused are extremely confused and obscure. They and obscure. They have no consciousness. have no consciousness.

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BodiesBodies

Given Leibniz’s ontology of monads Given Leibniz’s ontology of monads (immaterial substances); what about bodies (immaterial substances); what about bodies or physical objects?or physical objects?

Contemporary materialists can adopt an Contemporary materialists can adopt an eliminativist approach: there is nothing but eliminativist approach: there is nothing but physical substances and, strictly speaking, physical substances and, strictly speaking, there are no such thing as mental states. there are no such thing as mental states. Another alternative is to claim that mental Another alternative is to claim that mental states are reducible to state of the states are reducible to state of the body/brain.body/brain.

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Leibniz’s reductionismLeibniz’s reductionism

Reductionism about bodies.Reductionism about bodies.

Does Leibniz anticipate Berkeley’s Does Leibniz anticipate Berkeley’s phenomenalist account (phenomenalist account (esse es percipyesse es percipy), i.e. ), i.e. the view that each soul or monad is the view that each soul or monad is somewhat watching a private film?somewhat watching a private film?

When we say “Socrates is sitting” we mean When we say “Socrates is sitting” we mean that the concept Socrates is appearing to us that the concept Socrates is appearing to us and other who are concerned. and other who are concerned. ““Fa” can be translated into “It appears to me Fa” can be translated into “It appears to me that Fa”that Fa”

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Leibniz may not be a phenomenalist insofar as Leibniz may not be a phenomenalist insofar as he claims that bodies result from monads, i.e. he claims that bodies result from monads, i.e. that bodies are aggregate that result from that bodies are aggregate that result from monads.monads.

““Result from monad”: what does it mean?Result from monad”: what does it mean?

ResultingResulting.. What it is What it is notnot::

1.1. It cannot be a causal relation, since It cannot be a causal relation, since monads have monads have only internal causation. only internal causation. Monads produce their Monads produce their perceptual state by perceptual state by means of striving or appetition, means of striving or appetition, but they but they don’t produce bodies. don’t produce bodies.

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2. 2. The resulting relation cannot be one of The resulting relation cannot be one of whole to whole to parts. Monads have no parts and parts. Monads have no parts and bodies are not bodies are not composed of monads.composed of monads.

3. 3. Resulting is not identity. Leibniz doesn’t Resulting is not identity. Leibniz doesn’t say that say that bodies are identical with bodies are identical with aggregates of monads.aggregates of monads.

4. 4. Resulting is not supervenience, i.e. Resulting is not supervenience, i.e. bodies do not bodies do not supervene on certain sets of supervene on certain sets of monads as the monads as the goodness of an apple goodness of an apple supervenes on some of its supervenes on some of its physical physical properties.properties.

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Resulting = monads Resulting = monads expressexpress bodies bodies

We can correctly say that bodies are We can correctly say that bodies are founded in monads, but not that monads founded in monads, but not that monads are founded in bodies.are founded in bodies.

Each body stands in a privileged relation Each body stands in a privileged relation to a subset of the totality of monads which to a subset of the totality of monads which has the job of well-founding it.has the job of well-founding it.

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Leibniz provides metaphysical foundations Leibniz provides metaphysical foundations for its physics. for its physics.

The physical forces in bodies (e.g. kinetic The physical forces in bodies (e.g. kinetic energy) are grounded in the primitive energy) are grounded in the primitive forces of monads, i.e. appetition.forces of monads, i.e. appetition.

Leibniz is a reductionist in a looser sense.Leibniz is a reductionist in a looser sense.

He claims that there really are bodies (such He claims that there really are bodies (such as tables and stones). Yet facts about as tables and stones). Yet facts about bodies can in principle be derived from bodies can in principle be derived from facts about monads, the only true facts about monads, the only true substances in the universe.substances in the universe.

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Is Leibniz inconsistent in claiming that the Is Leibniz inconsistent in claiming that the only substances of the universe are monads only substances of the universe are monads and in also talking about corporeal objects? and in also talking about corporeal objects?

Leibniz seems to embrace both forms of Leibniz seems to embrace both forms of idealism and form of corporeal substances.idealism and form of corporeal substances.

The fact that Leibniz continues to speak of The fact that Leibniz continues to speak of corporeal substances doesn’t necessarily corporeal substances doesn’t necessarily mean that he is not committed to idealism. mean that he is not committed to idealism. He may be seen as offering a form of He may be seen as offering a form of reductionism.reductionism.

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The theory of the substantial bond The theory of the substantial bond ((vinculum substantiale)vinculum substantiale)

It is something above monads which It is something above monads which unifies the monads as an organism into a unifies the monads as an organism into a substantial whole.substantial whole.

An obscure theory (it emerged lately in An obscure theory (it emerged lately in Leibniz’s work), which should explain the Leibniz’s work), which should explain the unity of organisms: i.e. the difficulty of unity of organisms: i.e. the difficulty of joining different simple substances or joining different simple substances or monads existing in our body to make a monads existing in our body to make a unique, to make us.unique, to make us.