In every act or proposed act, Aquinas considers that the will aims towards some end – in other words there is something which is considered to be a good (whether it is, in fact, a good or not). Aquinas needs, therefore, to establish the aim or end towards which human actions are to be directed.
Aquinas’ answer is, perhaps, not unexpected. Considering that he was a Christian theologian writing from a world that was steeped in Christian thought only one final end could possibly be posited – and that is God. This raises the obvious question of those people who do not accept the existence of God and it might seem that their ends or aims would be different from those of the believer. Aquinas is by no means the only advocate of a natural law approach to morality and his understanding differs from others such as Aristotle due to his belief in a personal God. This leads Aquinas to maintain that not only do human beings in general have a purpose beyond death, but each individual also has a particular purpose which is directly related to each person’s talents and abilities. Hugo Grotius claimed in 1625 (in Prolegomena II) that the foundations of natural law would be valid even if there was no God and Aristotle would have agreed with this, but in the absence of God the understanding of natural law would be significantly different as there would then be no life after death and thus the purpose of human existence would be changed. In addition, if God did not implant natural law in human beings then it might be argued that there was no reason why an individual should obey natural law.
Aquinas’ approach is sophisticated and he seeks to address the problem of those who do not believe in God. Even such an individual would seek to fulfil his or her nature and to make the most of individual potentialities – it will therefore follow that such individuals would still incline to obey natural law, as it is in obeying this natural law that human potential is fulfilled. However, the ends that people seek are different and it may be possible to tell what ends they seek by looking at how they live – they may, for instance, look for money, power or reputation as ends in themselves and, if they do so, they will be making a mistake as to where their true happiness lies.
Aquinas does not simply assert that God is the final end for human beings – he considers alternatives. If, for instance, it is suggested that some form of sensual pleasure should be the final aim or end in life, Aquinas would reject this as it is then only the body’s appetites and potentialities that are being satisfied and animals can seek the same thing. Similarly scientific knowledge cannot be the end as this good could only be sought by a small number of people who have the academic ability. Having said this, Aquinas’ view that God is the final end for human beings may be regarded as an assumption and it can, of course, be challenged. However, if the assumption is accepted and if there is, indeed, a God who created the world and human beings, then it is perfectly sensible to claim (although, of course, not necessarily true) that human beings were created for fellowship with this God.
It is interesting and important that Aquinas considers that all human beings share a single nature and, therefore, there should be a single aim or objective for all human beings – this justifies him in rejecting knowledge as an aim (as only some people have the ability to seek this knowledge). The one thing that every person can desire is the vision of God which is promised for the next life. It is only this beatific vision which will be fully and completely satisfying for every human being and humans can choose to seek this or to turn away from it.
The power of reason is vital for Aquinas – reason can determine what acts are necessary for the good of a human being whether this is taking food or drink or acting morally. Any act that furthers the end for human beings is morally good (whether this is eating or giving to charity). However, this is not to say that the acts are ends in themselves because means and ends are not separable. As Copleston says:
… in the teleological ethic of Aristotle morally obligatory acts are not means to an end which is simply external to these acts, since they are a partial fulfilment of it; nor is the end something external to the agent … Aquinas followed Aristotle in holding that the final end of man consists in activity, and activity is obviously not external to the human agent in the sense that a picture is external to the artist … God is glorified by the highest possible development of man’s potentialities as a rational being, and every moral act of man therefore has an intrinsic value (p. 211).
Both Aquinas and Aristotle maintained that a person can acquire a habit or disposition to either vice or virtue. Virtuous habits should be fostered by repeated acts of virtue and human beings should live without excess, according to the ‘mean’ (which can broadly be defined as that which is in accordance with right reason). Aquinas and Aristotle both deplored excess in any form – the classic example from Aristotle is that the brave man is neither cowardly (one example of excess) nor foolhardy (another example of excess). It might seem difficult to fit this Aristotelian notion with Christian figures such as Mother Julian of Norwich, Teresa of Lisieux or Teresa of Calcutta, and Aquinas does consider this point as he does ask whether giving one’s goods away to the poor might be considered excess. His conclusion is that it would not if this action was inspired by Christ (S.T. 1a, 11ae, 64, 1, obj. 3) although it is hard to see how Aquinas could then resist a similar argument by many fanatical religious figures who claimed loyalty to Christ.
We have seen that Aquinas considers that natural law can be deduced by experience from looking at human nature and its purposes. Human beings have a duty to preserve themselves in existence (by, for instance, eating and drinking), to be rational and even to preserve the species. The last may seem self-evident, but it does not appear to fit well with the celibacy of priests in the Roman Catholic Church and, of course, Aquinas was himself a priest. Aquinas meets this point by saying that the need to propagate the race applies to the race as a whole:
The natural precept about taking nourishment must necessarily be fulfilled by every individual; for otherwise he could not be preserved. But the precept about generation applies to the whole community, which not only must be multiplied corporeally but also make spiritual progress. And so sufficient progress is made if some only attend to generation, while others give themselves to the contemplation of divine things … (S.T. 1a, 11ae, 152, 2, ad 1).
This is a neat way of overcoming the problem, but it is not clear which ‘ends’ must be fulfilled by the individual and which by the group and there could be debate about the allocation between these headings. Also if only some attend to spiritual progress, does this help only those individuals or the community as a whole? This might also open debate about the possibility of only a number of individuals being homosexually inclined since only some need to be heterosexual in order to propagate the human race.
Aquinas considered that from a general principle, such as the need to propagate the species, detailed rules can be deduced such as the need for monogamy and the education of children. However, it would be possible to challenge Aquinas on the first of these – by saying that, for instance, it is not self-evident that monogamy is the best way of propagating the species. Aquinas’ method is to begin with a general injunction that good is to be sought and evil avoided and then to unpack these by means of subsidiary principles (or perhaps assumptions would be a better word – although some might challenge this) that become more and more specific. It is not, however, a mere deduction of specific principles from general ones – at each stage Aquinas considers that the contemplation of human nature and its ends is required.
The problem is that at every stage the judgements being made may be challenged and there may be assumptions that govern the law that is deduced which may not be generally accepted. As an example, one might start with the general principle of propagation and then move to monogamy (although even this step might be challenged). One could then look at genital organs and consider their purpose – if their purpose is decided to be for procreation, then any use of these organs for other purposes such as pleasure (through masturbation, genital homosexuality or conventional sex using contraception) would be held to be wrong because they go against the intended purpose for these organs. However, who is to define the purpose? If, as part of the function of genital organs, one included as the purpose ‘that they are intended so that two people who love each other should be able to express their love and obtain pleasure in doing so and that propagation might, when appropriate, thereby take place’ then one might rule out masturbation and homosexuality, but not sexual