In Man's Search for Meaning, Viktor Frankl shares three core beliefs throughout the text.
First, individuals are driven by a desire for meaning as opposed to merely pleasure or power. When describing what distinguishes logotherapy from Freudian or Adlerian schools of psychoanalysis (which tend to orient human behavior around the pursuit of pleasure or power), Frankl says that he sees humans as meaning-oriented creatures. People need to feel they are living to some end, or they will inevitably feel their life is a waste. All the pleasure and power in the world means nothing if the individual does not feel as though they lived life with purpose. Ultimately, people can find meaning through work, love, or courage in the face of suffering.
Second, individuals can bear any sort of suffering as long as they give that suffering purpose. Both during his time in the Nazi concentration camps and his time as a psychiatrist, Frankl found that those who granted meaning to their suffering tended to bear up better psychologically than those who saw it all as arbitrary. He is not arguing that people should seek to suffer but that when suffering inevitably comes, facing it with courage can be enough to give it meaning. It is one's attitude that matters more than the suffering itself.
Finally, freedom and responsibility should go hand-in-hand in order for one to be able to live life to its fullest. Frankl famously said that the Statue of Liberty should be given a Statue of Responsibility as a counterpart. Freedom without responsibility becomes impulsive and can lead to its own sort of misery. When tempered by a sense of responsibility, freedom allows an individual to live a richer life. While Frankl discourages people from trying to find an overriding meaning to life, he does claim that everyone has the potential to find special meaning for themselves:
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. ... In a word, each man is questioned by life; and he can only answer to life by answering for his own life; to life he can only respond by being responsible. Thus, logotherapy sees in responsibleness the very essence of human existence.
Ultimately, Frankl's core beliefs present the ideal human life as one in which meaning is paramount. A life lived with purpose, rather than a life lived in avoidance of pain and in pursuit of pleasure, is the one that will allow an individual to be the most content.