This answer will have vastly different answers according to what the person world view is. This is greatly influence by what the person religion is and what he believes to be the meaning of life. A few quotes to illustrate.
Plato
Plato was one of the earliest, most influential philosophers to
date—mostly for realism about the existence of universals. In the
Theory of Forms, universals do not physically exist, like objects, but
as ghostly, heavenly forms. In The Republic, the Socrates character's
dialogue describes the Form of the Good. The Idea of the Good is ekgonos
(offspring) of the Good, the ideal, perfect nature of goodness, hence an
absolute measure of justice.
Enlightenment philosophy
The Enlightenment and the colonial era both changed the nature of
European philosophy and exported it worldwide. Devotion and
subservience to God were largely replaced by notions of inalienable
natural rights and the potentialities of reason, and universal ideals
of love and compassion gave way to civic notions of freedom, equality,
and citizenship. The meaning of life changed as well, focusing less on
humankind's relationship to God and more on the relationship between
individuals and their society. This era is filled with theories that
equate meaningful existence with the social order.
Classical liberalism
Classical liberalism is a set of ideas that arose in the 17th and 18th
centuries, out of conflicts between a growing, wealthy, propertied
class and the established aristocratic and religious orders that
dominated Europe. Liberalism cast humans as beings with inalienable
natural rights (including the right to retain the wealth generated by
one's own work), and sought out means to balance rights across
society. Broadly speaking, it considers individual liberty to be the
most important goal,[27] because only through ensured liberty are the
other inherent rights protected.
Kantianism
Kantianism is a philosophy based on the ethical, epistemological, and
metaphysical works of Immanuel Kant. Kant is known for his
deontological theory where there is a single moral obligation, the
"Categorical Imperative", derived from the concept of duty. Kantians
believe all actions are performed in accordance with some underlying
maxim or principle, and for actions to be ethical, they must adhere to
the categorical imperative.
Utilitarianism
The origins of utilitarianism can be traced back as far as Epicurus,
but, as a school of thought, it is credited to Jeremy Bentham,[28] who
found that "nature has placed mankind under the governance of two
sovereign masters, pain and pleasure", then, from that moral insight,
deriving the Rule of Utility: "that the good is whatever brings the
greatest happiness to the greatest number of people". He defined the
meaning of life as the "greatest happiness principle".
Nihilism
Nihilism suggests that life is without objective meaning. Friedrich
Nietzsche characterized nihilism as emptying the world, and especially
human existence, of meaning, purpose, comprehensible truth, and
essential value; succinctly, nihilism is the process of "the devaluing
of the highest values".[30] Seeing the nihilist as a natural result of
the idea that God is dead, and insisting it was something to overcome,
his questioning of the nihilist's life-negating values returned
meaning to the Earth.[31]
Pragmatism
Pragmatism, originated in the late-19th-century U.S., to concern
itself (mostly) with truth, positing that "only in struggling with the
environment" do data, and derived theories, have meaning, and that
consequences, like utility and practicality, are also components of
truth. Moreover, pragmatism posits that anything useful and practical
is not always true, arguing that what most contributes to the most
human good in the long course is true. In practice, theoretical claims
must be practically verifiable, i.e. one should be able to predict and
test claims, and, that, ultimately, the needs of mankind should guide
human intellectual inquiry.
Existentialism
Each man and each woman creates the essence (meaning) of his and her
life; life is not determined by a supernatural god or an earthly
authority, one is free. As such, one's ethical prime directives are
action, freedom, and decision, thus, existentialism opposes
rationalism and positivism. In seeking meaning to life, the
existentialist looks to where people find meaning in life, in course
of which using only reason as a source of meaning is insufficient; the
insufficiency gives rise to the emotions of anxiety and dread, felt in
facing one's radical freedom, and the concomitant awareness of death.
To the existentialist, existence precedes essence; the (essence) of
one's life arises only after one comes to existence.
Absurdism
In absurdist philosophy, the Absurd arises out of the fundamental
disharmony between the individual's search for meaning and the
apparent meaninglessness of the universe. As beings looking for
meaning in a meaningless world, humans have three ways of resolving
the dilemma. Kierkegaard and Camus describe the solutions in their
works, The Sickness Unto Death (1849) and The Myth of Sisyphus (1942):
Suicide (or, "escaping existence"): a solution in which a person
simply ends one's own life. Both Kierkegaard and Camus dismiss the
viability of this option. Religious belief in a transcendent realm or
being: a solution in which one believes in the existence of a reality
that is beyond the Absurd, and, as such, has meaning. Kierkegaard
stated that a belief in anything beyond the Absurd requires a
non-rational but perhaps necessary religious acceptance in such an
intangible and empirically unprovable thing (now commonly referred to
as a "leap of faith"). However, Camus regarded this solution as
"philosophical suicide".
Secular humanism
Per secular humanism, the human race came to be by reproducing in a
progression of unguided evolution as an integral part of nature, which
is self-existing.[42][43] Knowledge does not come from supernatural
sources, but from human observation, experimentation, and rational
analysis (the scientific method): the nature of the universe is what
people discern it to be.[42] Likewise, "values and realities" are
determined "by means of intelligent inquiry"[42] and "are derived from
human need and interest as tested by experience", that is, by critical
intelligence.[44][45] "As far as we know, the total personality is [a
function] of the biological organism transacting in a social and
cultural context."[43]
Logical positivism
Logical positivists ask: "What is the meaning of life?", "What is the
meaning in asking?"[48][49] and "If there are no objective values,
then, is life meaningless?"[50] Ludwig Wittgenstein and the logical
positivists said:[citation needed] "Expressed in language, the
question is meaningless"; because, in life the statement the "meaning
of x", usually denotes the consequences of x, or the significance of
x, or what is notable about x, etc., thus, when the meaning of life
concept equals "x", in the statement the "meaning of x", the statement
becomes recursive, and, therefore, nonsensical, or it might refer to
the fact that biological life is essential to having a meaning in
life.
Postmodernism
Postmodernist thought—broadly speaking—sees human nature as
constructed by language, or by structures and institutions of human
society. Unlike other forms of philosophy, postmodernism rarely seeks
out a priori or innate meanings in human existence, but instead
focuses on analyzing or critiquing given meanings in order to
rationalize or reconstruct them. Anything resembling a "meaning of
life", in postmodernist terms, can only be understood within a social
and linguistic framework, and must be pursued as an escape from the
power structures that are already embedded in all forms of speech and
interaction. As a rule, postmodernists see awareness of the
constraints of language as necessary to escaping those constraints,
but different theorists take different views on the nature of this
process: from radical reconstruction of meaning by individuals (as in
deconstructionism) to theories in which individuals are primarily
extensions of language and society, without real autonomy (as in
poststructuralism). In general, postmodernism seeks meaning by looking
at the underlying structures that create or impose meaning, rather
than the epiphenomenal appearances of the world.
Christianity
Though Christianity has its roots in Judaism, and shares much of the
latter faith's ontology, its central beliefs derive from the teachings
of Jesus Christ, as presented in the New Testament. Life's purpose in
Christianity is to seek divine salvation through the grace of God and
intercession of Christ. (cf. John 11:26) The New Testament speaks of
God wanting to have a relationship with humans both in this life and
the life to come, which can happen only if one's sins are forgiven
(John 3:16–21; 2 Peter 3:9).
In the Christian view, humankind was made in the Image of God and
perfect, but the Fall of Man caused the progeny of the first Parents
to inherit Original Sin. The sacrifice of Christ's passion, death and
resurrection provide the means for transcending that impure state
(Romans 6:23). The means for doing so varies between different groups
of Christians, but all rely on belief in Jesus, his work on the cross
and his resurrection as the fundamental starting point for a
relationship with God. Faith in God is found in Ephesians 2:8–9 –
"[8]For by grace you have been saved through faith; and that not of
yourselves, it is the gift of God; [9]not as a result of works, that
no one should boast." (New American Standard Bible; 1973). People are
justified by belief in the propitiatory sacrifice of Jesus' death on
the cross. The Gospel maintains that through this belief, the barrier
that sin has created between man and God is destroyed, and allows God
to change people and instill in them a new heart after His own will,
and the ability to do it. This is what the term reborn or saved almost
always refers to. This places Christianity in stark contrast to other
religions which claim that believers are justified with God through
adherence to guidelines or law given to us by God.
http://en.wikipedia.org/wiki/Meaning_of_life