Phil 30I W25 Lecture 6.1

Page 1: Introduction to Early Modern Philosophy

• Course Title: Introduction to Early Modern Philosophy

• Institution: UC Riverside

• Semester: Winter 2025

• Instructor: Matic Kastelec

Page 2: Lecture 6.1 - Leibniz on Substance and Mind-Body Relationship

Objectives:

• Understand Leibniz's rejection of Descartes’s notion of material substance.

• Analyze Leibniz’s positive account of substance and its significance in our understanding of the world.

• Explain why Leibniz rejects mind-body interactionism and occasionalism, highlighting his theory of pre-established harmony.

Page 3: Gottfried Wilhelm Leibniz (1646-1716)

Key Biographical Points:

• Born in Leipzig, Germany in 1646.

• Studied at the University of Leipzig (philosophy, law, math, etc.) starting in 1661.

• Earned doctorate in law, University of Altdorf in 1666.

• Had diverse careers: diplomat, lawyer, mathematician, scientist, philosopher.

• In 1672, moved to Paris; engaged with intellectuals like Huygens and Spinoza.

• Contributed to calculus, binary number system, symbolic logic.

• Published "New System" in 1695 and founded the Brandenburg Society (Berlin Academy of Sciences) in 1700.

• Met Peter the Great in 1711 to advise on education reforms.

Page 4: New System (1695)

• Full title: "New System of the Nature of Substances and Their Communication, and of the Union Which Exists Between the Soul and the Body."

Page 5: Philosophers and the Concept of "Substance"

• Clarification: Everyday use of "substance" might mislead; philosophical context differs.

Meanings of "Substance":

• Being or entity.

• An object distinguishable from its properties.

• An independently existing thing (as opposed to modes).

• The fundamental unit of reality.

Page 6: Mere Extension is Insufficient

• Leibniz critiques the mere consideration of extended mass and highlights the need for the notion of force, which belongs to metaphysics.

• He argues against reducing animals to mere machines.

Page 7: Is Matter a Substance?

Leibniz's Rejection of Cartesian Material Substance:

• States it’s impossible to find principles of real unity in mere matter, which lacks true unity as it is merely an aggregation of parts.

• Concludes: Without unity, there can be no substance.

Page 8: Argument Against Matter as Substance

1. Matter is defined by extension.

2. Extension implies infinite divisibility.

3. Divisibility leads to plurality.

4. Plurality lacks true unity.

5. True unity is necessary for substance; hence, matter cannot be substance.

Page 9: Leibniz on Substance

Characteristics of a Substance:

• Indivisible.

• Immaterial.

• Active, capable of perception and desire.

• Mind-like in its characteristics, although not all substances entail rational thought.

Page 10: Implications Without Such Substances

• Emphasizes that the essence of "I" (self) arises from the soul or form, signifying true unity.

• Without substantial unities, the material world lacks true reality, likening unities to organized machines or collectives like armies and flocks.

Page 11: Existence of Immaterial Substances

• Argues for real, substantial things through immaterial substances.

• Asserts atoms of matter contradict reason; true unities devoid of parts are necessary for actions and composition of substances.

Page 12: Recap on Leibniz's Philosophy of Substance

1. Critique of Descartes: Matter is not a substance.

2. Nature of substances: They possess true unity, are indivisible, immaterial, and active.

3. Significance: Substances are essential for the existence of selves and reality in things.

Page 13: Mind and Body According to Leibniz

Key Features of Pre-Established Harmony:

1. No direct influence among substances.

2. Each substance acts spontaneously according to its nature.

3. States of different substances align perfectly.

4. Harmony is established by God’s perfect design.

• Defines bodies as collections of mind-like substances.

Page 14: Possible Accounts of Mind-Body Relationship

• Interactionism (Descartes): Claims substances influence each other.

• Occasionalism (Malebranche): Postulates a divine mechanism for synchronization.

• Pre-Established Harmony (Leibniz): Proposes inherent coordination without direct interaction.

Page 15: Christiaan Huygens (1629-1695)

• Notable for invention of the pendulum clock.

• Presented his invention to King Louis XIV in 1659.

Page 16: The Way of Influence (Descartes)

• Leibniz critiques Cartesian interactionism, questioning how such influence occurs; denies interaction between finite substances.

Page 17: The Way of Assistance (Malebranche)

• Claims that a divine workman adjusts the clocks; while it avoids interaction, it improperly suggests ongoing miracles.

Page 18: The Way of Pre-Established Harmony (Leibniz)

• Clocks are designed to synchronize without direct influence.

• Avoids appeals to miracles or inexplicable interactions, explaining the appearance of interaction through natural laws.

Page 19: Pre-Established Harmony Explained

• God creates substances so each one produces its own states spontaneously and in conformity with others, establishing overall harmony.

Page 20: Summary

• Leibniz posits that matter, as mere extension, cannot be defined as substance.

• Substances are characterized by true unity and are fundamentally active, immaterial, and mind-like.

• While substances do not interact, they exist in pre-established harmony.