So far in the discussion, I think we now have 6 kinds of reasons why a doctrine might be considered important:

1. Experiential effect (in one’s life): (Andrew and Theo Geek, Reuben, Brad H)
2. link of a doctrine to orthopraxy (possibly identical to 1) (Reuben, probl. Andrew and Brad H.)
3. Necessity to salvation (Reuben)
4. Important to identity (Reuben)
5. Important as “JPT” just plain truth (Me)
6. If about God, important because about God (even if human importance not discernible), since in a relationship any knowledge of the other is important, and with God all the more so. (Me)

I don’t deny 1 + 2 as reasons for the importance of doctrine s (and linked to most doctrines that are important).
Concerning 3, some doctrines that important for this reason probably exist, although I would not necessarily emphasize the concept of doctrine at this point. I.e., for salvation, it is necessary to have faith in Christ, to repent, to acknowledge that Jesus is Lord, etc.–whatever doctrines are the doctrinal formulations of these could be seen to satisfy 3. Although, isn’t it the person of Christ in whom we have faith who is necessary for salvation? So it’s not the doctrine per se, but the doctrine is a way of stating what is necessary.
Regarding 4, I could see it as a source of importance in some cases. If I were Catholic, the primacy of the papacy would have to be important, whether I could see how it affected me.

My question: do you think there are valid instances of 5 and 6? I think there are. Although, I think that most of them would actually also have an impact along the lines of 1 and 2 and some might satisfy 3.

For example, to be specific. If I am persuaded that scripture teaches penal substitionary atonement (as I am–although scripture also gives other ways of understanding atonement, too–ransom, Christus Victor, etc.), is this an important doctrine, even if, for some reason, I cannot formulate a connection to 1 or 2?

Personally, I would like to affirm 5 and 6, even where I cannot find 1 or 2, although I believe that if you have a whole bunch of doctrines that don’t satisfy 1 or 2, something is probably wrong.

Just stumbled across your post here. Regarding your first question, I like to think that orthodoxy and orthopraxy ought to be intimately linked. In my opinion, theology for the sake of theology itself is irrelevant. The purpose of my theology is to help me live, and to help others do the same. So I believe the important doctrines are those which help me to think and live in a way more in line with Jesus and experience the kind of life God intended for me and those around me.

That isn’t the only reason people might consider a doctrine important. In the case of penal substitution, I know Christians who believe that I would be sent to hell if I were to not believe, trust and accept that this specific theory of atonement is the means of my salvation. So that’s another reason for importance of some doctrines – their importance for people’s eternal destinies. Hence, people may emphasize different doctrines depending on what they consider the criteria for God’s final judgment.

The last reason that comes to mind for people to place importance on particular doctrines is one of identity. For example, a Christian may identify themselves with a particular denomination or tradition and thus place importance on the doctrines peculiar to that tradition. This reason strikes me as not a very good one, but nevertheless I think it is a strong factor for many Christians.

I hope you found something interesting in all that ramble =)

I don’t think I misunderstood. I thought your point about not exceeding the guarantee of the cross excellent. In a way, every doctrinal system is an attempt at guaranteeing the church, and every system is in danger of over-guaranteeing the church, if the cross is not at the center.