Accessible version | Skip to content | Change your text size

Table of contents

Previous pageNext page

Writing your own evaluation

Click on the highlighted text to see the comments.

You now have a chance to attempt your own evaluation of a philosophical argument. The task in the Summarising section was to write a summary of Aquinas' 'Fifth Way'.

Read over Aquinas' ' Fifth Way' again and try writing your own comments on his arguments.

(For this exercise, limit your evaluation to about 100 words - a mini evaluation; bear in mind that the evaluation sections in Philosophy essays will normally need to be longer than this).

Word count: 0

Check your answer

Have a look at the following student evaluation of Aquinas' 'Fifth Way'. Note that we have combined the student's summary text of the 'Fifth Way' (from the summary writing task in the Summarising section) with his evaluation of it.

Can you identify where the student's summary stops and where the evaluation begins?

Sample summary and evaluation of Aquinas' Fifth Way

The fifth and final proof Aquinas has for the existence of God relates to what he calls 'the governance of the world'. He deduces that things that lack knowledge - that is birds, plants natural bodies - behave as if with purpose, and achieve or work toward certain ends. These natural bodies, Aquinas suggests, utilise the best means available to them, and almost always behave in the same way to produce these ends. This, Aquinas claims, is evidence of design. For:

...whatever lacks knowledge cannot move toward an end, unless it be directed by some being endowed with knowledge and intelligence... ( ibid, p 85)

Aquinas concludes that there is an intelligent being who directs all these bodies to their end. This is God.

I believe Aquinas' 'fifth way' can be challenged on several grounds. First there is an assumption in his argument that nothing in the natural world can be goal directed without the direction of something with 'knowledge and intelligence'. This is not necessarily the case - evolutionary theory for example seems to offer a perfectly naturalistic explanation of goal directedness in the natural world. Another problem is the assumption that, if there is an intelligent 'something' directing the world, that this is necessarily one single intelligence - what Aquinas calls 'God'. There is no particular reason for believing this is the case. Followers of animistic or polytheistic religions would say for example that this directing comes from a multiplicity of intelligences. Thus Aquinas' fifth proof for the existence of God appears flawed to me because it relies on several premises that are quite contestable.

Aquinas' Fifth Way

The fifth way is taken from the governance of the world. We see that things which lack intelligence, such as natural bodies, act for an end, and this is evident from their acting always, or nearly always, in the same way, so as to obtain the best result. Hence it is plain that not fortuitously, but designedly, do they achieve their end. Now whatever lacks intelligence cannot move toward an end, unless it be directed by some being endowed with knowledge and intelligence; as the arrow is shot to its mark by the archer. Therefore some intelligent being exists by whom all natural things are directed to their end; and this being we call God.

From The Summa Theologica of St. Thomas Aquinas

word outputDownload a printable version of this page (.doc)
Problems? Questions? Comments? Please provide us feedback.