About Thomas Aquinas & Natural Law
Aquinas created the Natural Law theory by using Aristotle's philosophy and applied it to Christian thinking. Aristotle said that good humans were those who fulfilled the purpose of human life, just as a good pencil case is one that holds all your things well. Aquinas argues that we can find out about what God wants ( and so what is the right thing to do) by considering natural purposes and functions. Aquinas, therefore promoted anything that would have been deemed a 'natural' human process. Aquinas's theory is similar to all the theories that I have previously looked at. It is still a set rule one should follow to deem what is right, like Kant and Bentham's theories, but is also more flexible and adjustable, like Fletcher's ideas.
Natural Law on the Robin Hood Problem
Aquinas, like Kant, would most likely give the man in to the police. As robbing is not a 'natural' human function, Aquinas would've deemed it as immoral. The man did not 'have' to rob the bank to give to charity. If he really needed to give to charity and he thought the charity needed the money badly, he could've donated his own money, or held a fundraiser for the charity to benefit from. If the man could not afford to give to the charity himself or organize a fundraiser, he could've spread awareness, or not given to the charity at all. The man did not have to rob the bank to give to the charity, and Aquinas would agree as it is definitely not a necessary human process.