The Metaphysics of Agency: Avicenna and His Legacy
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The Metaphysics of Agency: Avicenna and his Legacy by Kara Richardson A thesis submitted in conformity with the requirements for the degree of Doctor of Philosophy Graduate Department of Philosophy University of Toronto ©Copyright by Kara Richardson 2008 The Metaphysics of Agency: Avicenna and his Legacy Doctor of Philosophy, 2008 Kara Richardson Department of Philosophy University of Toronto Abstract This dissertation begins with the Islamic philosopher Avicenna, who transforms Aristotle’s conception of the efficient cause in the Metaphysics of his Shifā’. Its first goal is to examine the arguments which constitute Avicenna’s metaphysical account of agency. Its second goal is to examine Scholastic disputes about the causal powers of natural agents that arise in connection with his view. In its final chapter, it relates Medieval debates about efficient causality to Descartes’ account of the causal powers of bodies. One of the original features of Avicenna’s account of agency is his argument for the claim that the existence of contingent things requires an efficient cause. This aspect of his view was influential in the Latin West. Avicenna also holds that the cause of the existence of contingent things is an incorporeal principle, which he describes as an agent who “bestows forms”. I argue that Avicenna fails to resolve the tension between this claim and his commitment to an Aristotelian account of generation. This failure sets the stage for Avicenna’s role in Scholastic disputes about the causal powers of natural agents in cases of generation. Both Aquinas and Suarez attribute to Avicenna the view that generation requires the creation of form. They argue that generation occurs through natural processes. Suarez’s ii view includes the claim that the substantial form of a substance is an immediate efficient cause of its actions. Suarez defends this claim against other Aristotelians, who hold that a substantial form gives being to a composite substance as a formal cause and that the actions of substances depend directly on their accidents alone. Descartes claims in his letter to Regius of January 1642 that it is absurd to hold that substantial forms are immediate principles of action. He thinks that bodies act in virtue of their modes. Here Descartes sides with those Aristotelians who hold that the actions of substances depend directly on their accidents alone. I argue that this aspect of Descartes’ view tells against Daniel Garber’s claim that his denial of substantial forms deprives bodies of causal efficacy. iii Acknowledgements I would like to thank my supervisors, Deborah Black and Marleen Rozemond, for their engagement with this project and for their encouragement and support throughout my graduate education. I would also like to thank Peter King and Martin Pickave for questions and comments on the final draft of my dissertation. iv Table of contents Abstract_______________________________________________________________ii Ackowledgements ______________________________________________________ iv Table of contents________________________________________________________v Introduction___________________________________________________________1 Chapter 1 Avicenna’s metaphysical account of agency_______________________ 11 Section 1.1 Causality as an object of study in metaphysics _______________________13 Section 1.2 The “common” conception of agency _____________________________23 Section 1.3 What comes to be can’t persist through itself________________________32 Section 1.4 Agents are sufficient in themselves for their effects ___________________46 Section 1.5 Avicenna’s hierarchy of agents___________________________________55 Chapter 2 Avicenna on the coexistence of agents and their effects ____________61 Section 2.1 True vs. accidental agents_______________________________________63 Section 2.2 The case of the building________________________________________66 Section 2.3 The case of the son ___________________________________________79 Section 2.4 Avicenna on potentiality and actuality _____________________________84 Section 2.5 Avicenna on causes of individuals and causes of species _______________93 Section 2.6 The case of elemental transformation _____________________________97 Chapter 3 Aquinas and Avicenna on efficient causality and generation ________ 111 Section 3.1 Aquinas on God as the cause of the existence of contingent individuals __ 114 Section 3.2 Aquinas on natural agents as instrumental causes of generation_________ 118 Section 3.3 Aquinas on the causal powers of natural agents _____________________128 Section 3.4 Aquinas vs. the creation of form ________________________________133 Section 3.5 Avicenna on the substantiality of form, matter and the composite_______137 Section 3.6 Aquinas and Avicenna on substantial generation ____________________143 Chapter 4 Suarez on substantial forms as efficient causes ___________________146 Section 4.1 Suarez on natural agents as causes of generation: introduction__________150 Section 4.2 The instrumental role of accidents in generation ____________________156 v Section 4.3 The influence of substantial forms in generation ___________________160 Section 4.4 The action of separated accidents _______________________________168 Section 4.5 Suarez on natural agents as causes of generation: conclusion___________170 Section 4.6 The late Medieval conception of substantial form ___________________172 Chapter 5 Descartes on the causal powers of bodies without substantial forms _ 181 Section 5.1 Scholastic debates about the efficient causality of substantial forms______185 Section 5.2 Descartes’ account of the causal powers of bodies___________________187 Section 5.3 Can Cartesian bodies have causal powers? ___________________________192 Section 5.4 Causal powers as properties _____________________________________200 Conclusion _________________________________________________________203 Bibliography ________________________________________________________207 vi Introduction Readers of Aristotle are familiar with his account of the four causes in Physics 2.3 and Metaphyiscs 5.2. In both of these texts, Aristotle identifies four principles through which we can grasp “both coming to be and passing away and every kind of natural change”.1 One is “that out of which a thing comes to be”, e.g., the marble of the statue; we call this the material cause.2 Another is the form or archetype of the thing made, which Aristotle identifies with the definition of its essence; in the case of a statue of the Virgin Mary, the formal cause is its Marian shape.3 The third is a cause “in the sense of end or that for the sake of which a thing is done”, e.g., the statue was made in order that we might revere her Holiness; we call this the final cause.4 Fourth is the “the primary source of the change or rest”, e.g., the sculptor who makes the statue; we call this the efficient cause.5 Medieval philosophers retain Aristotle’s four causes, but they modify his account of them and their relations with one another in various ways. This dissertation examines efficient causality in the work of three Medieval philosophers, namely, Avicenna, Aquinas and Suarez. In its final chapter, it relates Medieval debates about efficient causality to Descartes’ account of the causal powers of bodies. Medieval philosophers typically object to Aristotle’s definition of the efficient cause on the ground that it encompasses only agents of change. This objection seems odd, since Aristotle identifies and distinguishes his four causes in order that we may use them to understand “both coming to be and passing away and every kind of natural 1 Aristotle. Physics 2.3 194b 21. All quotations of Aristotle are from The Complete Works of Aristotle, ed. Jonathan Barnes. Princeton: Princeton University Press, 1984. 2 Aristotle. Physics 2.3 194b 24-5. 3 Aristotle. Physics 2.3 194b 27-8. 4 Aristotle. Physics 2.3 194b 33-4. 5 Aristotle. Physics 2.3 194b 30-32. 1 2 change”.6 Medieval philosophers reason that since scientific inquiry concerns existence as well as change, it seeks causes of existence, as well as causes of change. Notice that the claim that scientific inquiry concerns existence and seeks its causes does not entail that existence stands in need of an efficient cause. An Aristotelian could hold that to identify Socrates’ formal and material causes suffices to explain his existence. Roughly speaking, this is Aristotle’s view, but not the view of Medieval Aristotelians. The Medieval view that Socrates stands in need of an efficient cause of his existence is born from their view that Socrates is a contingent thing. A contingent thing is something actual whose existence is merely hypothetically necessary. The existence of Socrates is hypothetically necessary if Socrates must exist given the existence of some efficient cause or set of efficient causes. In other words, the hypothetically necessary is not necessary in itself, but rather is necessary through its efficient cause or causes. Thus understood, the claim that the existence of Socrates is merely hypothetically necessary seems uncontroversial. It is compatible with our ordinary belief that if things had been otherwise, e.g., if Socrates’ parents had not encountered each other, then Socrates would not exist. The difference between our ordinary view of individuals as contingent beings and the view upheld by many Medieval philosophers has to do with the distinction between coming to be and existence. According to Medieval philosophers, our ordinary belief that if things had been