Since the story in Thomas Malory's 1485 Tales of King Arthur, some people have engaged in the quest for the Holy Grail, allegedly the cup from which Jesus drank at the Last Supper. Their hope, in vain, is that possession of the Grail would bring coherence and purpose to the meaning of life. Different answers have been given through history to the questions of the purpose of human existence, and the meaningfulness of life.

The crucial question can be raised, is there meaning in life and is it related to a significant goal or purpose? Consider a few answers for the human condition. Classical liberalism considered individual liberty to be the most important goal for living. Kantianism postulated a single moral obligation, the Categorical Imperative derived from the concept of duty. The English philosopher Jeremy Bentham, 1748-1832, regarded as the founder of modern utilitarianism, defined the principle that that it is the greatest happiness of the greatest number that is the measure of right and wrong, and that natural law and natural rights were "nonsense on stilts." He argued that nature has placed people under the governance of two sovereign masters, pleasure and pain.

In the 20th century, intellectual speculation has focused on the concept that it is absurd that people should engage in a quest and should search for meaning of existence in a world where life has no meaning. This point of view was made this well known by Albert Camus, who discussed the absurdity of life and the inevitability of death, and thus one could not know the meaning of life. Committed to individual and moral freedom, he rejected the usefulness of scientific and metaphysical answers to the question of the meaning of existence.

Yet if life may not have been created with predetermined purpose, people have sought to suggest a purpose or meaning. From the beginning of intellectual speculation with Plato and Aristotle to postmodernists, quantum mechanics and string theory, today, thinkers have given vastly different answers to the basic question of the meaning of life, whether there is there purpose in life, and is life significant?

Sometimes, the answer has a hallucinatory character. The most popular painting in the Museum of Modern Art, NYC, "Starry Night," by Vincent van Gogh, illustrates the fascination with stars and death. He wrote of it, "as we take a train to travel on earth, we take death to reach a star."

Today, science, biology, chemistry, physics, have joined philosophical speculation to try to understand the universe, our place in it, a journey of discovery of the universe and humanity. Advances in medicine and technology have liberated individuals and changed relationships, personal and social. The mantra now is that any speculation about the meaning of life conceived by individuals is related to a variety of factors: wealth, employment, health, education, security, religious and philosophical views, and life expectancy.

Like the meaning of life, the view of quality of life, and the search for order, coherence, purpose, is similarly charged in multiple fashion with individual ideas, values, and norms; knowledge of empirical facts about oneself, degree of happiness, enjoyment in activities, and anxiety about death.

Two factors are inherent in this view of quality. One is that people evaluate both the positive and negative aspects of their existence. The other is that though some ethical judgments are universal across cultures, others are culturally specific.

As societies have developed with marked increase in longevity, the interest in quality of life has become more meaningful than any quest for the meaning or quantity of life itself. This has become significant for professional health care personnel, medical specialists and clinicians, all of whom are conscious of its importance in diagnosis. Advances in the medical field have helped keep people alive for a longer period. Noticeably, the medical profession now considers the quality of life of patients when deciding on whether to advocate life sustaining medical treatment for severely ill patients. Medical treatment now aims to increase the quality as well as the length of survival.

What should be considered in evaluating the concept of quality of life, a complex phenomenon? One definition of the concept, by the World Health Organization, is that it is "an individual's perception of their position in the context of the culture in which they live and in relation to their goals, expectations, standards, and concerns." More evidently, it is the ability to perform a normal activity and live a fulfilling life and have satisfaction in spite of suffering disease, injury, impediments. Yet, definition of quality is elusive, differing across cultures, regions, demographics, in relation to physical and mental health, work environment, social and economic status, sense of security, goals, expectations, ability to perform a normal social role.

Two factors are relevant. One is that people have different expectations at different times, and they may vary about them in relation to the trajectory of any illness they suffer. Experiences change expectations. The other issue is that evaluations of quality vary in relation to social class, sex, and ethnic group, among other factors. Individuals are likely to assess quality by comparing expectations of health with experience.

Concepts like quality, happiness or emotional well-being, and a subjective state of mind cannot be measured as can GDP in financial terms. They are multidimensional with emotional, physical, material, social, aspects. They can be seen in different realms, embracing subjective and objective facets, related to personal, community, national, and even global factors. Subjectively, it entails assessment of happiness, pleasure, fulfillment, satisfaction with life. Objectively, involved are social, economic, health factors: variation between individuals, and within an individual over time, psychological well-being, member of family, education, religious beliefs, goals in life, recreation, leisure time, and health care, and intangibles such as security of one's job, political stability, degree of individual freedom, and conditions of environment.

The emphasis on quality does not resolve the issue of what makes life worth living, a subjective assessment. It does not lead to a quest for any Holy Grail, nor a search for the existence of any wisdom or dedication to some higher purpose. But it is increasingly meaningful today in practical terms for both incapacitated individuals and medical practitioners.