“Optimism doesn’t wait on facts. It deals with prospects. Pessimism is a waste of time.”

Variant: Pessimism of the spirit; optimism of the will.

Examples of self-translation (c. 2004), Quotes - Zitate - Citations - Citazioni

1840s, Essays: First Series (1841), Compensation
Context: We feel defrauded of the retribution due to evil acts, because the criminal adheres to his vice and contumacy, and does not come to a crisis or judgment anywhere in visible nature. There is no stunning confutation of his nonsense before men and angels. Has he therefore outwitted the law? Inasmuch as he carries the malignity and the lie with him, he so far deceases from nature. In some manner there will be a demonstration of the wrong to the understanding also; but should we not see it, this deadly deduction makes square the eternal account.
Neither can it be said, on the other hand, that the gain of rectitude must be bought by any loss. There is no penalty to virtue; no penalty to wisdom; they are proper additions of being. In a virtuous action, I properly am; in a virtuous act, I add to the world; I plant into deserts conquered from Chaos and Nothing, and see the darkness receding on the limits of the horizon. There can be no excess to love; none to knowledge; none to beauty, when these attributes are considered in the purest sense. The soul refuses limits, and always affirms an Optimism, never a Pessimism.
His life is a progress, and not a station. His instinct is trust. Our instinct uses "more" and "less" in application to man, of the presence of the soul, and not of its absence; the brave man is greater than the coward; the true, the benevolent, the wise, is more a man, and not less, than the fool and knave. There is no tax on the good of virtue; for that is the incoming of God himself, or absolute existence, without any comparative. Material good has its tax, and if it came without desert or sweat, has no root in me, and the next wind will blow it away. But all the good of nature is the soul's, and may be had, if paid for in nature's lawful coin, that is, by labor which the heart and the head allow. I no longer wish to meet a good I do not earn, for example, to find a pot of buried gold, knowing that it brings with it new burdens. I do not wish more external goods, — neither possessions, nor honors, nor powers, nor persons. The gain is apparent; the tax is certain. But there is no tax on the knowledge that the compensation exists, and that it is not desirable to dig up treasure. Herein I rejoice with a serene eternal peace. I contract the boundaries of possible mischief. I learn the wisdom of St. Bernard, — "Nothing can work me damage except myself; the harm that I sustain I carry about with me, and never am a real sufferer but by my own fault."

Source: The Anatomy of Human Destructiveness (1973), p. 483
Context: Optimism is an alienated form of faith, pessimism an alienated form of despair. If one truly responds to man and his future, ie, concernedly and "responsibly." one can respond only by faith or by despair. Rational faith as well as rational despair are based on the most thorough, critical knowledge of all the factors that are relevant for the survival of man.

1990 Chairman's Letter http://www.berkshirehathaway.com/letters/1990.html
Letters to Shareholders (1957 - 2012)

The Miracle of Mindfulness (1999)
Source: The Miracle of Mindfulness: An Introduction to the Practice of Meditation
Context: To think in terms of either pessimism or optimism oversimplifies the truth. The problem is to see reality as it is. A pessimistic attitude can never create the calm and serene smile which blossoms on the lips of Bodhisattvas and all those who obtain the way.

Section 9 : Ethical Outlook
Founding Address (1876), Life and Destiny (1913)
Context: Theologians often say that faith must come first, and that morality must be deduced from faith. We say that morality must come first, and faith, to those whose nature fits them to entertain it, will come out of the experience of a deepened moral life as its richest, choicest fruit.
Precisely because moral culture is the aim, we cannot be content merely to lift the mass of mankind above the grosser forms of evil. We must try to advance the cause of humanity by developing in ourselves, as well as in others, a higher type of manhood and womanhood than the past has known.
To aid in the evolution of a new conscience, to inject living streams of moral force into the dry veins of materialistic communities is our aim.
We seek to come into touch with the ultimate power in things, the ultimate peace in things, which yet, in any literal sense, we know well that we cannot know. We seek to become morally certain — that is, certain for moral purposes — of what is beyond the reach of demonstration. But our moral optimism must include the darkest facts that pessimism can point to, include them and transcend them.

Optimism (1903)