Have you ever asked the question about reincarnation, about who or what decides about the present circumstances of our individual lives? One answer, a newer, might I say New Age version, is that we as souls determine beforehand, before birth, what is to be accomplished, the lessons to be learned, and probably with whom we learn these spiritual lessons. This is a kind of free-will, self-deterministic worldview of the explanation of the purposes of human existence: we come to learn spiritual lessons that we prenatally determine.
The more traditional view of all this brings in the Law of Karma (Law of Cause and Effect or Law of Reward and Punishment). The concept of karma moves the present circumstances of our lives away from the soul deciding its own goals towards what seems to me to be a bit more mechanistic and impersonal worldview--the Law works in cause-effect application to the life of the soul in each incarnation. Thus, the soul contains within itself the results of its past existences, its past actions, which are deterministic of present circumstances.
The first view, the soul-decides-its-spiritual-goals worldview probably appeals to Western ideals of primacy of individual free will, in a kind of spiritual individualism. The second view, the more traditional, relies on a "natural" law of the universe, in that karma is applied as impersonal judgment.
Hope this helps. I write this only as background information, about which I expect no one to believe. I'm not sure I believe it (reincarnation and karma) anymore myself. Presently I'm in a period when I seem to have no definite beliefs at all, when I have faith that having no or few definite beliefs is itself a faith that I find acceptable (and probably the most honest state for me).
I seem to be moving away from what I might label a more Hinduistic worldview (in 1985 I was initiated into Surat Shabd yoga or, older name, Radha Soami [it is not Hinduism per se, but a centuries old form of meditation practice], and traveled to an ashram in India four times over the years) towards, once again, a more Buddhistic worldview (I read Zen in the early 1970s and at various times associated with various Buddhist groups and initiated into a Taoist sect, in Taiwan, in 1988). All of this I am increasingly folding into an ecofeminist theology, a pneumatology of Earth Spirit. Thus, as I have long self-labeled, I am pagan-Buddhist-Baptist (and more).
Almost as a prayer and simultaneously a mantra, I still hold to my article of faith that I, we all, are, and should aspire to be, "conscious co-workers of the divine plan," which, of course, presupposes that there is a "divine" and a "plan." It works for me, without my fervently holding belief in the presuppositions, although there does, indeed, seem to be a "plan" to the madness (actually, I have some faith that there is a plan).
I also seem to be simplifying my beliefs to a very few precepts:
My body is the temple of the Spirit;
my mind is my church.
And, in my mind, which I do not dualistically separate from my body, I practice Minding and Awarenessing.
These things I DO believe. Beyond these, I have almost no (definite) beliefs.
However, to turn mystical and poetic (as a project of Awarenessing?), I write this:
My prayers are pure mystical incense
wafting to Heaven.
My tears are clear fragrant nectar
bathing the stars.