Here is a great article on contraception and Catholicism. In addition to calling out the Church's issues on contraception, it really crystallizes the core of my disagreement with the Catholic Church's doctrines, or rather their approach to doctrines. The Catholic church does not just set sacred revelations in stone, they also make courses of reasoning and arguments untouchable and infallible. The problem with Catholic dogma is not (as is the case with some protestants) that it puts the Bible and the creeds beyond all doubt and scrutiny, but that it places human reasoning (of a certain sort) above all doubt and scrutiny. It has made a philosophy part of its religion.
This is apparent in the case of contraception. According to the Church the 'wrongness' of contraception is not a matter of sacred doctrine but a matter of 'natural' reason -- we do not need the holy spirit or the scriptures to tell us that contraception is wrong, we can use our heads. But this raises the interesting problem that huge numbers of people have reasoned about contraception and can see nothing wrong in it. And why should they? There is no Euclidean proof for the immorality of birth control. Contraception is only wrong if one accepts the reasoning of Aquinas and other church-approved philosophers. And why do they have authority? Because the church says that they do.
Thus the 'natural reason' notion is nothing more than dogma dressed up, but it is worse than that. The core revelations of Christianity are (I would argue) quite restricted -- I could rattle off the apostle's creed and say that about sums it up. If a church says that its core and unchanging doctrine is the creed, it leaves its believers plenty of room to debate, discuss and interpret faith for themselves, to say nothing of other matters of their life that do not touch on doctrinal issues directly. I see it all the time in every church (including Catholic ones, somewhat illicitly). But if a church proscribes not just a set of beliefs but a manner of thought, then it seeks to circumscribe all thought and opinion among its members. This is politically troubling in a democracy such as ours, and would be a larger problem if most American Catholics weren't Americans first and Catholics second. Theologically, it depends upon a certain view of the Holy Spirit as having acted in the past, and simply maintaining the body of Christ as it once was, through adherence to tradition and hierarchy. It directly contradicts any notion of the Spirit working among all believers through all times as they reason for themselves and debate amongst themselves. Dogmatic Thomism is a doctrine for a faith that only seeks to preserve the past; in so doing I doubt it will have a future.
The irony of this is that I like Thomas Aquinas, at least at the broadest level. Thomist acceptance of the role of reason has prevented the Catholic church from joining the ranks of evolution denialism. But what I like most is the idea of 'natural good' itself (which for the Vatican's dogmatists includes rejecting birth control). For Thomas, nature is good (as stated in genesis) and man is capable of good things even without the grace of God through Christ. This is a wonderful idea for 2 reasons:
1) it is life affirming and world affirming, in contrast to the sometimes bitterly ascetic cast of Christianity (see Pascal, Blaise')
2) In affirming that people can determine good things by using their natural reason, 'natural good' allows for non-Christians to be good -- this is most apparent in the case of Dante's virtuous heathens. Religiously the virtuous heathen might still be damned, but in terms of civil society virtuous heathens can make a decent citizen as well as a Christian can.*
In both of these cases I am more interested in taking the idea of 'natural good' to its logical conclusion rather than in the conclusion that Thomas may have reached with it -- Living 700 years and change after him, my first principles and modes of thinking are rather different. And this brings me back to my first point -- in nearly making Thomas' entire argument sacrosanct, the Catholic church has prevented people from taking his ideas in extremely productive directions.
*Of course, Thomas didn't really have an idea of a 'civil society' in the modern sense, what with writing in the 13th century and all.