Natural law theory only succeeds because it takes human nature seriously. Discuss

Aquinas’ theory of natural law is a meta ethical theory that primarily occupies a teleological ethical perspective. Aquinas comes from a posteriori background and thus believes that reason along side careful reflection on the world is what leads us to have an understanding on moral rightness. However, the success of the theory, as I shall show in this essay, is significantly held back by the basis and background of Aquinas’ theory, with much authority coming from the Bible and the teaching of Aristotle, that promotes a rather optimism and over-hopeful idea of human nature. This optimistic view of human nature is one that is undermined in Augustine’s teaching and understanding of human will and one that shatters the validity of his moral philosophy. Aquinas rejected Plato’s idea of the physical world as something unimportant and shadowy and instead chose to follow Aristotle who claimed that the world is exceedingly important as it provides us with an integral source of information when understanding the world and human nature. Aquinas thus borrowed Aristotle’s idea of the four causes and argued human nature naturally entails the ability to work out what is right through studying the causes. To an extent this could give Aquinas’ theory validity as he has moved on from the imaginative writings of Plato, as discussed by Anthony Kenny, and has instead focused on the slightly more scientific methods of observation shown in Aristotle. This enables him to have a further and deeper insight and understanding of human nature and thus allows him to perhaps create a far more valid moral philosophy. However, despite the claim to use empirical methods of observation Aquinas’ theory is still based on an optimism and wishful approach to understanding human nature; one that undermines this original strength. This is shown as Aquinas argued that human nature is essentially good as natural law is present within everyone as we can visibly see everyone striving for perfection and avoiding evil. His argument is based on the idea that no one would actively pursue evil and those that do are following a merely apparent good that has resulted out of an error of judgement. He continues his argument with his belief that human nature can, through the use of reason, distinguish between real and imagined goods. A major flaw in this understanding of human nature is that looking historical there are plentiful examples where humans have not been able to distinguish between these real and apparent goods or even worse have actively chosen to follow evil. A prime example would be Hitler who mercilessly and continuously chose to commit the undoubtably atrocious massacre of the Jewish nation. Unlike the belief of Aquinas Hitler did not seem to have a rational moral compass or an inner conscience or sense of natural law to direct him thus suggesting Aquinas’ misinterpretation of human nature is in fact the biggest failure of his moral philosophy.