The following is not what I believe, but merely an argument that ran through my head, and which intrigued me:
We express through language the notion that we exist as "persons" or "spirits" (there is no objective proof for inner existence), so it is reasonable to suggest that our personal existence is a product of language, itself. The notion of personal existence should not be confused with objective existence, the latter being ultimately only theoretical because there is nothing that is truly objective. Nevertheless, the compulsion to distinguish between mechanistic existence and spiritual / personal existence is an analog to the dichotomy of objectivity and subjectivity.
Language, in a philosophical sense, is our path to personal existence. Mechanistic organisms that are bound by deterministic principles are occupied by a meme that causes those organisms to express, through language, a sense of personal existence, a sense of spirit, a sense of soul, a sense of mind, a sense of self. This personal existence is merely make belief - an arbitrary construct. It is this meme that is the origin of and the source of sustainance for personal / inner existence, and it is propagated between members of the species - passed on from one to the other through language.
One could then postulate that beings, without the lexicon to express this sense of personal existence, do not have a sense of personal existence in the way that we know it. One could conclude that the existential dilemma is merely a side effect of language, itself, and that this dilemma does not exist in the absence of language.