This uniqueness and singleness which distinguishes each individual and gives a meaning to his existence has a bearing on creative work as much as it does on human love. When the impossibility of replacing a person is realized, it allows the responsibility which a man has for his existence and its continuance to appear in all its magnitude. A man who becomes conscious of the responsibility he bears toward a human being who affectionately waits for him, or to an unfinished work, will never be able to throw away his life. He knows the "why" for his existence, and will be able to bear almost any "how."
—Viktor E. Frankl, Man's Search for Meaning, Boston, MA: Beacon Press, 2006, p. 79-80.
One should not search for an abstract meaning of life. Everyone has his own specific vocation or mission in life to carry out a concrete assignment which demands fulfillment. Therein he cannot be replaced, nor can his life be repeated. Thus everyone's task is as unique as his specific opportunity to implement it.
—ibid., pp. 108-109.
This emphasis on responsibleness is reflected in the categorical imperative of logotherapy, which is: "Live as if you were living already for the second time and as if you had acted the first time as wrongly as you are about to act now."
—ibid., p. 109.
Thus far we have shown that the meaning of life always changes, but that it never ceases to be. According to logotherapy, we can discover this meaning in life in three different ways: (1) by creating a work or doing a deed; (2) by experiencing something or encountering someone; (3) by the attitude we take toward unavoidable suffering.
—ibid., p. 111.