S for transcendent aspects of the divine, we’ve already conceded that if any exist they defy analysis, constituting an inscrutable mystery.
But let’s consider the argument that anything totally unascertainable should be presumed not to exist, citing not as much the likely naturalism of the remaining unknown in the cosmos (what about beyond the cosmos?) but Ockham’s Razor (principle of parsimony) which says that the simplest hypothesis which can explain an idea is most often the right one.
This principle, if applied to the maximum on religious issues, would leave us hard-pressed to justify so much as a decent pantheism. Such a situation represents an opportunity for a technically-precise use of the word atheist, a moniker encompassing at least three classes of disbelief—
First, philosophers of religion often use the term when referring to a nontheist, one who, while perhaps recognizing some kind of religious or belief system— even some kind of pantheistic world soul or cosmic consciousness— rejects the orthodox theistic conception of a deity having both immanent and transcendent aspects.
Second, the general public most frequently applies the atheist designation to an unbeliever, one who finds a deity of any sort, orthodox or unorthodox, untenable, but not all reasons for faith (for example, an individual might place his hope in some version of secular humanism).
Third, in its most extreme form, nihilist, the adherent wears the title of atheist with pride, disclaiming credence not only in anything beyond the known natural order but in any faith or hope, believing that life is meaningless.
(There’s little need at this time to further bisect each of these three groups into professed and practiced forms, because voicing a belief is a form of action— the two blend into one active level.)
Since many at least recognize something extraordinary in the life-giving capability of even only the natural, scientifically-observable world, many if not most atheists are probably of the first or second categories, nontheists or unbelievers.
Even then they wouldn’t forfeit the right to declare as a foundation of hope the essence that, if they were theists, they might call divine immanence— being itself. We have to believe, at least at present, that a propensity to life exists, because we exist.
While atheists may be opposed to admitting the likelihood of any transcendent aspects of deity, they might not object to simply designating certain aspects of being— phenomena of natural existence that coincide with what theists call divine immanence and ranging anywhere from natural beauty to art, goodness, life, and love— as ultimate reality.
Many atheists do object to any insertion of the word God or other reference to deity into their vocabulary, even as idea apart from reality, and with good reason— consider the reaction of a believer if the atheist contrived to redefine a portion of the believer’s agenda as atheistic.
So what theists might call divine we’ll alternately, for the benefit of nontheists, refer to as ultimate (yet still fully natural as opposed to supernatural).