A
AndyT_81
Guest
Friends - apologies in advance for the length of this OP. I wanted to cover off as many of the common objections and misunderstanding with regards to Aquinas’ first way in the first post.
Change is a sure reality. What is change? Some would attempt to reduce change to local motion, i.e. the movement of this thing to that new position. However, it can be argued that this doesn’t capture all changes within the corporeal world. For instance, the transition to a higher energy state of an electron by an incident photon, or the change of the spin of a particle cannot meaningfully be said to be simply a matter of local motion. In addition, non-physicalists would not readily agree that changes in substances are fully reducible to local motion involving their constituent parts (though it would include such motion). Therefore, an understanding of change is needed that is more universal, and this can be found in the Aristotelian notions of potency and act. Local motion is possible because physical objects have the potential to change their position within space. This potential (or potency) is actualised by some other thing or component. A notion of potentiality is necessary to explain local motion in any case – what effects the local motion of certain objects is dependent on certain potentials within those objects. For instance, take the postulated Weakly Interacting Massive Particle (WIMP), if it exists, its local motion will be affected only by weak force and gravitational interactions – due to some property that is possesses, from which flows its potentiality for only those interactions. Therefore, it has the potential to interact with particles which have mass, but it does not have the potential to interact with other particles via the electromagnetic force. The possible causes which actualise these potencies are therefore limited. In the same way, other particle’s local motions are dependent on their nature, which contains certain potentialities with respect to possible interactions. With regards to the electron example – due to their essential nature, electrons have the potential to move into higher energy states via the absorption of a photon.
Therefore, all change can be described via this consideration of potency and act, and this is essentially what the sciences study whether individual scientists know it or not.
To move out of the sub-atomic realm and to more mundane and common examples, the acorn has within it the potential to become an oak tree – but this potential needs to be actualised by other factors external to the acorn itself (soil, water, correct temperature etc.), it cannot actualise that potency itself. For a potential to actualise itself, it would have to be potential and actual at the same time and in the same respect – which of course is absurd. Note however, that pure potentiality cannot actualise anything – the potential of a piece of wood to combust will not in itself cause another piece of wood to combust. Therefore, the first way can be phrased as such (reverting to “change” instead of the unwieldy but more precise “reduction of potency to act”):
An essentially ordered series is different, and it is a series of this sort that (4) depends on. The elements in this type of series do not have independent causal power, rather their causal power depends entirely on the “previous” (whereby I am using previous to express ontological, not temporal, order) member in the series – for this reason there must be a first member in the series from which all the members derive their causal power. The archetypical example of this type of series is a hand using a stick to push a rock. The continuous movement of the rock is dependent on the continuous movement of the stick, which in turn is dependent on the continuous movement of the hand – as such the hand actualises the potency of the rock for spatial movement in the presence of friction, and the stick is purely instrumental in this series. If the hand vanished, the rock would no longer be continuously moving because the stick would lose its causal power to actualise that potential. Of course, the series does not end there – the hand is kept in motion by the movement of muscles, which are in turn activated by certain motor neurons, which are in turn being activated by other neurons, whereby the neurons are being “fired” via the action of ions and other chemical compounds, which in turn operate due to their molecular structure, caused by atomic properties and actions, then sub-atomic properties and action and on and on. If any of these elements ceased to be, the rock would no longer be in continuous movement.
cont…
Change is a sure reality. What is change? Some would attempt to reduce change to local motion, i.e. the movement of this thing to that new position. However, it can be argued that this doesn’t capture all changes within the corporeal world. For instance, the transition to a higher energy state of an electron by an incident photon, or the change of the spin of a particle cannot meaningfully be said to be simply a matter of local motion. In addition, non-physicalists would not readily agree that changes in substances are fully reducible to local motion involving their constituent parts (though it would include such motion). Therefore, an understanding of change is needed that is more universal, and this can be found in the Aristotelian notions of potency and act. Local motion is possible because physical objects have the potential to change their position within space. This potential (or potency) is actualised by some other thing or component. A notion of potentiality is necessary to explain local motion in any case – what effects the local motion of certain objects is dependent on certain potentials within those objects. For instance, take the postulated Weakly Interacting Massive Particle (WIMP), if it exists, its local motion will be affected only by weak force and gravitational interactions – due to some property that is possesses, from which flows its potentiality for only those interactions. Therefore, it has the potential to interact with particles which have mass, but it does not have the potential to interact with other particles via the electromagnetic force. The possible causes which actualise these potencies are therefore limited. In the same way, other particle’s local motions are dependent on their nature, which contains certain potentialities with respect to possible interactions. With regards to the electron example – due to their essential nature, electrons have the potential to move into higher energy states via the absorption of a photon.
Therefore, all change can be described via this consideration of potency and act, and this is essentially what the sciences study whether individual scientists know it or not.
To move out of the sub-atomic realm and to more mundane and common examples, the acorn has within it the potential to become an oak tree – but this potential needs to be actualised by other factors external to the acorn itself (soil, water, correct temperature etc.), it cannot actualise that potency itself. For a potential to actualise itself, it would have to be potential and actual at the same time and in the same respect – which of course is absurd. Note however, that pure potentiality cannot actualise anything – the potential of a piece of wood to combust will not in itself cause another piece of wood to combust. Therefore, the first way can be phrased as such (reverting to “change” instead of the unwieldy but more precise “reduction of potency to act”):
- Change occurs
- Nothing can change itself
- Whatever causes change must itself be either changing or be an unchanged changer
- An infinite series of changers is impossible
- Therefore there must exist an unchanged changer (a being of pure actuality)
An essentially ordered series is different, and it is a series of this sort that (4) depends on. The elements in this type of series do not have independent causal power, rather their causal power depends entirely on the “previous” (whereby I am using previous to express ontological, not temporal, order) member in the series – for this reason there must be a first member in the series from which all the members derive their causal power. The archetypical example of this type of series is a hand using a stick to push a rock. The continuous movement of the rock is dependent on the continuous movement of the stick, which in turn is dependent on the continuous movement of the hand – as such the hand actualises the potency of the rock for spatial movement in the presence of friction, and the stick is purely instrumental in this series. If the hand vanished, the rock would no longer be continuously moving because the stick would lose its causal power to actualise that potential. Of course, the series does not end there – the hand is kept in motion by the movement of muscles, which are in turn activated by certain motor neurons, which are in turn being activated by other neurons, whereby the neurons are being “fired” via the action of ions and other chemical compounds, which in turn operate due to their molecular structure, caused by atomic properties and actions, then sub-atomic properties and action and on and on. If any of these elements ceased to be, the rock would no longer be in continuous movement.
cont…