Maybe? There are no clerics as a class. Instead, there are a collection of different divine, miraculous things that can be done, by tapping and establishing relationships with divine powers of one sort or another. “Divine powers” is left deliberately vague there, because humans have some vague theories about it all and they’re all vaguely wrong.
As a rough summary: Oceana is the biggest thing around here, but doesn’t care about humanity (worshiping Her is largely fruitless, and She derives energy from the ancient Engine left in this Sphere by Those That Created The Sphere). There are also a few other “elemental” or “fundamental” entities on a similar scale (the Sun, the Great Eye) who also don’t need worship for their power, either because they are sponsored by Oceana, parasitize Her, or are drawing from Somewhere Else. Almost everything smaller than that would love to talk about arranging worship-energy-for-favors, thank you. And as implied, there are Things Much Bigger Than The Local Cosmology, like Those That Created The Sphere.
The primary divine, miraculous things that can be done:
Divine spells are built using the rules in Player’s Companion using the arcane modifier rather than divine; or for spells not covered by PC, are at +1 spell rank. So, for example, cure serious wounds ends up as a sixth rank arcane spell. These draw on or bind a variety of miscellaneous entities, and a chunk of the Mortal Wounds Table and Tampering With Mortality Table can be seen as consequences of that.
(It’s also worth noting that any literate person of some reasonable education can attempt to impress a spell into their mind, given a scroll from which to do it, and divine spells are the same in this regard; just beware backfires. A spell-casting class just has a certain number of spells they can automatically impress without chance of failure.)
Anyone with a holy symbol and faith can attempt to Turn undead (effectively as a cleric of half level). Rightous Turning taken once lets someone Turn as a cleric of the same level; taken the second time, has its usual effects.
The rules for divine power still exist, and can be used by arcane spell-casters willing to work as an intermediary between a congregation of believers and this or that “celestial” entity. If someone got really ambitious, cities in the setting act as a kind of “celestial” entity; a lot of godlings wandering the setting now were once rulers of good-sized city-states . . .
Also, patronage means certain proficiencies are treated as (G)eneral proficiencies: Divine Blessing, Righteous Turning, divine spell-like abilities (again using the rules in PC), and so on. The character has to establish a patronage relationship for each such proficiency, and follow the rules of that entity.