Private interpretors have expressed both views. Both Attar's Language of the Birds and Bahá'u'lláh's Seven Valleys, which Shaykh Muhyi'd-Din has probably read, use valleys as symbols of developmental stages. Thus it would seem that the reader's pre-dispossession would be to see Four Valleys in the same light unless there were clear textual signposts pointing in another direction.
David Langness excerpts his book The Seeker's Path (1997) at http:../letters/seven.valleys.html. He takes the single wayfarer view: He (Bahá'u'lláh) outlines the spiritual journey, saying that "those who progress in mystic wayfaring are of four kinds" (p. 49). This more recent, simplified version of the traditional seven-stage path in the Seven Valleys parallels other four-stage maps drawn by psychologists, searchers and thinkers."
On the other hand, Dr. Stockman and others have suggested that the four valleys are four distinct paths to God. In support, they point out that seekers are referred to as "residents" in each given valley rather than wayfarers that journey from one valley to the next.
There are statements in the text of Four Valleys that seem to support both of these views.
Much can be said in support of the multiple paths view. For example the First Valley opens with the statement, "If the travelers seek after the goal of the Intended One (maqsud)..." One who attains this station "is pleasing unto God." The implication is that maqsud is a complete goal in its own right and not merely a stage in the seeker's path.
The Second, Third and Fourth Valleys each open with a similar conditional statement: "If the wayfarer's goal be the dwelling of the Praiseworthy One..", "If the loving seekers wish to live within the precincts of the Attracting One..." and "If the mystic knowers be of those who have reached the beauty.." While the latter statement is not specifically contingent on the wayfarer's wish, there are numerous references to dwellers in this valley, e.g. "The exalted dwellers in this mansion do wield authority in the court of rapture." (p. 60)
Finally there is Bahá'u'lláh's statement that "four kinds of wayfarers are referred to. "those who progress in mystic wayfaring are of four kinds" (p. 49). Thus there are several points that would support the idea that the four valleys are different paths and that individuals seekers choose to dwell in a particular valley or in literal terms choose their path to God.
In contrast to "dwellers" are the indications of a progression in nearness to God from one valley to the next. For example of those in the third valley it is said, "On this plane, neither the reign of reason (reference to second valley) is sufficient nor the authority of self (reference to first valley)... They see but the inner reality of the Beloved." This references to the first two valleys indicate knowledge of and progress beyond those stages. The reference to "inner reality" likewise indicates greater spiritual attainment in this plane.
Further, valley four is said to be the "apex." The wayfarer "must abandon all that men possess" to attain it. In view of the station of Poverty in Seven Valleys, it is natural to see the last of the four valleys as a similar spiritual end-of-the-road. It is hard to imagine that a seeker could attain to this level of spiritual growth without traversing the previously discussed valleys. Thus the four valleys are seen as "stages" of spiritual development.
In the introduction to Marzieh Gail's translation of Seven Valleys and Four Valleys, Robert L. Gulick, Jr. alludes to both "four stages of the human heart" and "four kinds of mystic wayfarers" but leaves the problem unresolved.
"It sets forth four ways in which the Unseen is seen, the four stages of the human heart, and the four kinds of mystic wayfarers in quest of the Intended One, the Praiseworthy One, the Attrracted One, the Beloved. The four divine states are given in this verse from the Quran (57:3) ^He is the first and the last; the Seen and the Hidden; and He knoweth all things.'"
Since there is merit in both perspectives, a way must be found to conflate them. One way to do that would be to recognize the optional choice of paths granted to "valley dwellers" while at the same time recognizing a progression that "wayfarers" may choose. Thus there is a progressive development from the lower to the higher valleys. Some settle in a valley and become "dwellers" while others choose to travel on to further spiritual growth in succeeding valleys. This is not to say that progress is necessarily linear between these valleys or that all must start in the first valley. It is conceivable that a seeker would start in the second valley, that of reason, without having traversed the valley of self.