AQUINAS

first way

• the unmoved mover 

• aquinas argued that nothing in the world would be in motion unless it was being moved by something else 

Emphasis on dependency, rather than going back in time until a beginning was found 

• used the idea that god sustains the universe and tried to show that we wouldn’t have a universe of change and motion without a first mover 

• the continued changes/ movements are because of the continued existence of a mover which we call god 

Change requires going from potential to actual 

• Depends on something that is actual which cannot merely depend on other potential things, so there must be something of pure actuality 

• a thing that is purely actual with no potential cannot change, as it is an unmoved mover/ uncaused causer 

proof of first way

• p1= we observe that there are things in motion 

• p2= motion is the actualisation of a thing’s potential to be in motion 

• p3= a thing can only come to be in motion by being moved 

• p4= a mover must be something that is actual (i.e. in a state of actuality) 

• p5= a thing cannot move itself 

• c1= so, all things in motion must have been moved by a mover, which was also moved by another mover 

• p6= there cannot be an infinite regress of movers, otherwise there would be no first mover, therefore no motion 

• c2= therefore, there must be a first mover, which itself must be unmoved (as it is pure actuality) → that thing we call god. 

SECOND WAY

• the uncaused causer (atemporal causation). this argument is v similar, except it replaces the idea of change and motion with the concept of cause 

Relationship between cause and effect 

• as ontologically real but not temporal, although they are consistent with a temporal understanding of cause and effect 

• they point to the logical implications of there being sustaining causes. this is why especially the second way called cosmological arguments from atemporal causation 

Attempts to show that god must exist as the first mover 

• the word ‘first’ in the concept of a first cause/ mover is not meant to indicate it being ‘first’ in time, but ontologically first in the sense that motion and causation are ontologically dependent on it 

THIRD WAY

• contingency

• he is arguing that we can agree that everything in the universe is contingent 

• contingent things need something else to bring them into existence, so nothing would have ever started. 

• there would still be nothing- unless there is some other being, capable of bringing other things into existence but being independent of everything else, or ‘necessary’ 

• it would have to be a being which is not caused, and which depends on nothing else to continue to exist- and this, aquinas thought, would be god 

1st/2nd way STRENGTH: parmenides

• based on causal principle, which is that every being 

• has a cause, or that every contingent being has a cause of its existence 

• ex nihilo nihil fit (nothing comes from nothing) → stems back to Parmenides who argues that its not possible for an event to happen without a cause, otherwise something could come from nothing, which is absurd 

COUNTER to parmenides

• lawrence kraus and alan guth add evidence from modern physics which states that the universe has zero total energy and therefore required no energy to be created 

• therefore, the universe could have come from nothing 

1st/ 2nd way WEAKNESS: synthetic

• A synthetic argument, therefore not proved, only inferred 

• There doesn’t appear to be anything incoherent in the idea of an event/ thing existing without a cause. 

• it is contradictory 

• so the causal principle can only be justified on posteriori grounds, which make it a synthetic truth 

• the problem is, claims based on experience cannot be known w/o certainty to be true in all cases, so the universe could exist w/o a cause 

COUNTER to synthetic

• could be defended by arguing that the universality of the causal principle is justified through induction 

• we have experienced many causal interactions, all of which involve the conjunction of cause and effect 

• from this we can infer that all effects have a cause 

• it is possible that this may be false, however the evidence so far suggests that it is true and we are therefore empirically justified in accepting the causal principle 

3rd way STRENGTH: ultimate explanation

• strengths of cosmo from contingency is their seeking of an ultimate explanation rather than only a first cause 

• they focus more fundamentally on the nature of things 

• beings have causal relations, but also ontological status, i.e. contingency/ necessity 

• contingent beings and series must have an external explanation since it is their nature to depend on something else for their existence 

3rd way WEAKNESS: fallacy of composition

• it is a fallacy to assume that what is true of a things parts must also be true for the whole 

• e.g if you build a wall out of small bricks, that does not necessarily mean that the wall will be small 

• hume uses the eg of a finite set of contingent beings (20 particles) to argue that experience shows that parts of the universe are contingent and have an explanation, this doesn’t mean the universe itself as a a whole must also be contingent 

• cosmo a posteriori arguments commit fallacy of composition by assuming that the universe has a cause when all we experience is that part of the universe has a cause 

COUNTER to FoC

• copleston points out that contingency arguments dont actually appear to make an inference from parts to whole, they argue that a series of contingent things must have an external cause 

• p1= a series is either caused/ uncaused 

• p2= if a series is uncaused, reason for its existence must be internal to it, making it necessary 

• p3= no amount of contingent things can be necessary, not even an infinite number of them, so a series of contingent things cannot be necessary 

• c1= so a series of contingent things must have an external cause like a necessary being