The stages would optimally line up something like this:2
|2||Concrete Operational||Instrumental Exchange||Mythic-Literal|
|3||Early Formal Operations||Mutual Interpersonal Relations||Synthetic-Conventional|
|4||Formal Operations (Dichotomizing)||Social Systems and Conscience||Individuative-Reflective|
|5||Formal Operations (Dialectical)||Social Contract, Individual Rights||Conjunctive|
|6||Formal Operations (Synthetic)||Universal Ethical Principles||Universalizing|
I say "optimally" because moral and faith development do not always keep pace with cognitive development. Ken Wilber likes to cite the example of Nazi doctors as people who may have been very intelligent (highly developed cognitively), but whose moral development was obviously lagging far behind. Cognitive development is necessary but not sufficient for development in other areas (or along what Wilber calls "lines"). Both Fowler and Wilber make this point.3
Wilber has argued that different developmental theories describe different lines, which is similar to the increasingly popular notion of multiple intelligences (IS, 59). The lines develop in each individual relatively independently of one another:
A person can evidence very high development in some lines (e.g., cognitive), medium development in others (e.g., interpersonal), and low in yet still others (e.g., moral). (Wilber, IS, 59)
A nice chart showing some of these lines, and how they correspond to each other can be seen here (opens new window).
Some Objections to Developmental Theories
There are some people who reject developmental theories, so I thought I would address that a little bit.
One argument I’ve encountered on the web is that some people don’t neatly fall into any one stage as described by a particular theory. For instance, Fowler’s Synthetic-Conventional stage is a conformist stage, and by the way Fowler describes it, one would expect adults who inhabit that stage to have very conventional views. How does one explain the existence of conformist progressives?
This reflects a failure to grasp the distinction between “contents” and “structures.” Some contents are more likely to be found in some structures than others, but there is no necessary relationship between them. Someone raised in a progressive family might well inhabit the Synthetic-Conventional stage and still hold progressive views. “Contents” refer to what we think; “structures” concern how we think about it.
A more serious and legitimate concern is that hierarchical models can be used used by the powerful for ideological purposes, with the oppression and marginalisation of others being the inevitable result. They invariably see themselves as the most developed, and relegate everyone who disagrees with them to lower levels. (See Pope Benedict’s comments about what constitutes “adult faith” in this article by John L. Allen, Jr. for a recent example of this.)
This is a legitimate concern, there’s no doubt about that. But the fact that an idea can be abused does not mean it’s mistaken. Besides, as Wilber has never tired of pointing out, those who reject hierarchies (a common enough problem among postmodernists) inevitably assert their own: To reject hierarchical theories in favour of non-hierarchical ones is itself to create a hierarchy. Wilber argues that we have to distinguish between “natural hierarchies” (which are not good or bad, but simply happen to exist) and “dominator hierarchies” (which are bad).
Another related-but-different argument is that developmental theories are “elitist.” I must admit, this particular argument doesn’t resonate with me. Are we to suppose that all people are equally adept at all things?
Wilber addressed this in an article in What Is Enlightenment? magazine a few years ago:
But isn't this view of mine terribly elitist? Good heavens, I hope so. When you go to a basketball game, do you want to see me or Michael Jordan play basketball? When you listen to pop music, who are you willing to pay money in order to hear? Me or Bruce Springsteen? When you read great literature, who would you rather spend an evening reading, me or Tolstoy? When you pay $64 million for a painting, will that be a painting by me or by Van Gogh?
All excellence is elitist. And that includes spiritual excellence as well. But spiritual excellence is an elitism to which all are invited. We go first to the great masters —to Padmasambhava, to St. Teresa of Avila, to Gautama Buddha, to Lady Tsogyal, to Emerson, Eckhart, Maimonides, Shankara, Sri Ramana Maharshi, Bodhidharma, Garab Dorje. But their message is always the same: let this consciousness be in you that is in me. You start elitist, always; you end up egalitarian, always.
For a nice take on this issue in a editors’ blog for the same magazine (now called EnlightenNext), read this.
 I don't recall Fowler ever using the term "spiritual intelligence," but Ken Wilber makes the point that this is essentially what Fowler is talking about (and I happen to agree that it is an apt term); see Wilber, IS, 69.
 Piaget development scheme ended with formal operations (which most people reach in adolescence). The gradations of “dichotomizing,” “dialectical,” and “synthetic” have been identified by Fowler. Similar gradations beyond mere formal operations are found in Wilber’s work, though the terminology he uses tends to change from one book to the next. Fowler’s “dichotomizing,” “dialectical,” and “synthetic” are, respectively, “rational mind,” “pluralistic/meta-systemic/early-vision logic,” and “paradigmatic/middle vision-logic” in Wilber. There is no single source for this information – as I said, Wilber changes his mind about what he would like to call them – but one place would be SES, 623n.6.
 See Fowler, Stages of Faith, 65; Wilber, SES, 689n.46.