aquinas' 5th way

regularity of succession

• Aquinas observed that natural objects/beings do not behave randomly, but moved towards a certain goal or purpose (end/telos). 

• The idea is that things we observe in the world are goal-directed. For example, flowers can move in alignment with the sun throughout the day to get more sunlight.  

regularity of succession e.g. of oak tree

• An acorn can grow into an oak tree. 

•  Water falls as rain and then evaporates as part of the water-cycle.  

• The planets orbit the Sun. 

•  Everywhere we look, Aquinas wants us to notice that objects do not behave randomly but with regularity in a goal-directed way. This shows that it is not mere chance that objects behave in this way. 

  • there are consistent and predictable patterns in the natural world, which suggest the universe operates according to established laws rather than by chance. 

natural objects

• Thomas Aquinas argued that natural objects (which lack intelligence) move towards specific purposes in a predictable way. Since they cannot direct themselves, an intelligent being (God) must be guiding them.  

• An arrow moves towards its target, but it has not intelligence to do so by itself 

• The arrow requires an archer to direct it towards it goals 

• Similarly, natural objects like planets or biological processes lack intelligence, yet they move in ordered and purposeful ways. 

• Therefore an intelligent being must be directing them. 

STRENGTH: mcgrath

• The advantage is that Aquinas carefully positioned his arguments to not claim too much. Paley adopts the same approach. They both accept that the design argument at most shows there is some designer of great power, but it doesn’t prove the Christian God in particular. 

• A. McGrath characterises Aquinas’ natural theology as showing an “a posteriori demonstration of the coherence of faith and observation” which shows the “inner consistency of belief in God”.  

• The design argument shows that it is reasonable to believe in a designer. Christian belief is an case of belief in a designer, so Christian belief is reasonable. 

•  Aquinas claims this supported faith.  

COUNTER to McGrath

• The support and value for faith provided by an argument for some generic designer is very low. 

• There are an infinite number of Gods we could imagine.   

• A designer might not even be a God. It could be 

• Furthermore, simply showing the logical consistency of God with observation is insufficient. If that strengthens faith, then that shows that faith is irrational. 

• It’s not rational to believe something simply because it is consistent with observation. Actual evidence is required. 

• So, if the design argument was used to support belief in some generic God, that would be valid. However, it is not valid to use it to support belief in any particular God. 

WEAKNESS: Hume’s ‘committee of Gods’ objection

• Hume argues that even if we had evidence of design in the universe, that would not support the claim that it was designed by the God of classical theism. 

•  It could have been made by a junior God, apprentice God – or even a God who died.  

• There could be multiple designers – ‘a committee of Gods’. So, the design argument doesn’t even justify monotheism. 

COUNTER to Hume

• Swinburne claims that Hume’s points here are correct and that the design argument cannot prove that the designer has the attributes of the God of classical theism. Other arguments will be needed for that. 

• However, Swinburne thinks that Ockham’s razor can be used against some of Hume’s claims here.

• One God being responsible for the design of the universe is a simpler explanation than multiple.

• Swinburne also points to the uniformity of the laws of physics as suggesting a single designer 

• Regardless, Hume’s critique doesn’t work against a posteriori arguments based in Aquinas’ style of natural theology (that Paley and Swinburne also adopt). They only seek to show that it is reasonable to believe in a designer. Hume’s insistence that we cannot know which type of designer there is does is irrelevant because that point is never denied by these proponents of the design argument