is a philosophical
theory about causation
which says that created substances cannot be efficient causes
of events. Instead, all events are taken to be caused directly by God
Himself. (A related theory, which has been called 'occasional causation', also denies a link of efficient causation between mundane events, but may differ as to the identity of the true cause that replaces them). The theory states that the illusion of efficient causation between mundane events arises out of God's habitual causing of one event after another. However, there is no necessary connection between the two: it is not that the first event causes
God to cause the second event: rather, God first causes one and then causes the other.
Islamic theological schools
The doctrine first reached prominence in the Islamic theological
schools of Iraq
, especially in Basra
. The ninth century theologian Abu al-Hasan al-Ash'ari
defended the notion of an utterly omnipotent God who could will absolutely anything (even that a perfectly good man could be sent to hell), and that nothing can endure for more than one instant without being recreated by God. These Ash'arite
occasionalist doctrines were continued by Abu Hamid Muhammad ibn Muhammad al-Ghazali
, an 11th century philosopher based in Baghdad
. Al-Ghazali, a fierce critic of Neoplatonic
-influenced Islamic philosophers
such as Al-Farabi
and Ibn Sina
, is famous for his claim that when fire and cotton are placed in contact, the cotton is burned directly by God, not by the fire.
Because God is usually seen as rational, rather than arbitrary, his behaviour in normally causing events in the same sequence (ie, what appears to us to be efficient causation) can be understood as a natural outworking of that principle of reason, which we then describe as the laws of nature. Properly speaking, however, these are not laws of nature but laws by which God chooses to govern his own behaviour (his autonomy, in the strict sense) - in other words, his rational will.
This is not, however, an essential element of an occasionalist account, and occasionalism can include positions where God's behaviour (and thus that of the world) is viewed as ultimately inscrutable, thus maintaining God's essential transcendence. On this understanding, apparent anomalies such as miracles are not really such: they are simply God behaving in a way that appears unusual to us. Given his transcendent freedom, he is not bound even by his own nature. Miracles, as breaks in the rational structure of the universe, cannot occur, since God's relationship with the world is not mediated by rational principles.
One of the motivations for the theory is the dualist
belief that mind and matter are so utterly different in their essences
that one cannot affect the other. Thus, a person's mind cannot be the true cause of his hand's moving, nor can a physical wound be the true cause of mental anguish. In other words, the mental cannot cause the physical and vice versa. However, occasionalists generally also held that the physical could not cause the physical either, for no necessary connection could be perceived between physical causes and effects. Thus, Occasionalism brought in God to fill this gap, since what God willed was
taken to be necessary.
The doctrine is, however, more usually associated with certain seventeenth century philosophers of the Cartesian school. There are hints of an occasionalist viewpoint here and there in Descartes's own writings, but these can mostly be explained away under alternative interpretations. However, many of his later followers quite explicitly committed themselves to an occasionalist position. In one form or another, the doctrine can be found in the writings of: Johannes Clauberg, Claude Clerselier, Gerauld de Cordemoy, Arnold Geulincx, Louis de La Forge, François Lamy, and (most notably), Nicolas Malebranche.
Hume's arguments, Berkeley and Leibniz
These occasionalists' negative argument, that no necessary connections could be discovered between mundane events, echoed certain arguments of Nicholas of Autrecourt
in the fourteenth century, and were later taken up by David Hume
in the eighteenth. Hume, however, stopped short when it came to the positive side of the theory, where God was called upon to replace such connections, complaining that 'We are got into fairy land [...] Our line is too short to fathom such immense abysses.' Instead, Hume felt that the only place to find necessary connections was in the subjective associations of ideas within the mind itself. George Berkeley
was also inspired by the occasionalists, and he agreed with them that no efficient power could be attributed to bodies. For Berkeley, bodies merely existed as ideas in percipient minds, and all such ideas were, as he put it, 'visibly inactive'. However, Berkeley disagreed with the occasionalists by continuing to endow the created minds themselves with efficient power. G.W. Leibniz
agreed with the occasionalists that there could be no efficient causation between distinct created substances, but he did not think it followed that there was no efficient power in the created world at all. On the contrary, every simple substance had the power to produce changes in itself
. The illusion of transeunt efficient causation, for Leibniz, arose out of the pre-established harmony
between the alterations produced immanently within different substances.