You’ve got to be a fairly sophisticated philosopher to even have an opinion on some of the subjects the Church has pronounced upon.
Basically a Catholic believes that Jesus is God, and that He was crucifed and rose again in order to save mankind from their sins. So we believe that men are sinful, and unworthy of eternal life, but that Jesus has changed that situation.
We also believe that Jesus founded the Church as the main instrument of that salvation, that this Church is the same organisation as the current Roman Catholic Church, and that it has not ceased to be effective though any major blunder that would make it no longer meannigfully the Church that Jesus founded.
We also believe that the most important thing the Church does is to offer the sacraments - baptism, confirmation, communion, confession, marriage, ordination, and last rites - and that these are effective in salvation. In the case of some of them, like confession, it is very easy to see how they are effective. In other cases, like communion, the sacrament acts on a more mystical level.
We also believe that the church can make rules for its members from time to time. Some of these, as with any organisation, are for the good of the club. Others are interpretations of Jesus’ teachings to fit modern conditions. Examples are; that one must attend Mass every Sunday, that one may not remarry after divorce, that abortion is prohibited, in some places, that where Catholic education is offered one must choose it for one’s children, that fasting is necessary during Lent. Some of these a Catholic can quibble with, or argue that the rules should not be as they are, but you must accept the Church’s authority to make these sorts of rules to be a member in good standing.