What is it that allows some of us to be hopeful in a world full of tragedy and injustice, where time and chance have their way with everyone, and where we face defeat in the end? Apart from a comforting religious faith it requires some trick of the mind to be able to derive pleasure and significance from the moment. Not everyone can do it. The lifetime prevalence of depression in the population has been estimated at 15-20%, while at any given moment around 10% of us are so beset by sadness and loss of personal significance that we qualify for a formal diagnosis of depression

    Given the state of the world it is hardly surprising that many people harbor doubts about the future. Pessimists, those most prone to depression, almost invariably consider themselves "realists," and watching the news it's hard to argue against the proposition that things are bad and getting worse. And yet our individual happiness in the present moment is largely dependent on what we anticipate. Our beliefs about the future constitute self-fulfilling prophesies: we get not what we deserve but what we expect. This truth can be seen most vividly in our interactions with other people. Those we approach with trust and openness tend to respond helpfully. Conversely, if we treat people with suspicion, they are likely to reciprocate.

    To be hopeful is not unselfish. On the contrary it is in our self-interest to risk the occasional disappointment that optimism implies in order to benefit from the more frequent experience of realized hopes. The habitual mask of the pessimist is similar to that of the depressive: a fixed frown of discontent and unhappiness. In fact, the triad of perfectionism, pessimism, and discouragement is a familiar precursor to and accompaniment of clinical depression. The logic is unavoidable: those who demand too much of themselves and others are bound to be unhappy in an imperfect world. Like most emotions （anger, anxiety, love）, unhappiness is contagious; it feeds on itself and demands to be shared. There is a story of two girls assigned to clean a stable. One focuses on the material she is shoveling, the other thinks that, "There must be a pony around here somewhere."

    To some extent hope or the lack of it is, like many of our attitudes, a product of our experience. There is an area of psychology called "learned helplessness" that concerns itself with the consequences to people when they conclude that they have little choice in what happens to them. If we assume that our efforts are unrelated to the outcomes in our lives we develop an outlook of pessimism and passivity. Optimism requires that we believe that we can favorably influence our fates.

    How we react to setbacks in our lives is a particularly good test of how hopeful we are. If we see some bad outcomes as being inevitable in a world in which our control is limited, we can nevertheless retain our confidence in our ability to change things for the better. If we react to adverse events by feeling discouraged and powerless and engage in a process of self-blame, we are unlikely to imagine that we can improve the situation. Eventually, our skepticism about changing things for the better hardens into an habitual attitude. Or as one bookstore visitor said, "I almost bought a book about how to think positively, but then I thought, 'What good would that do?'"

    It usually doesn't take long to find out whether you are in the presence of an optimist or pessimist. One of the best indicators of how someone else is feeling is the mood they evoke in us. If being around another person causes us to feel discouraged, it is a fair bet that this is, at least in part, a reflection of their outlook. Conversely, optimism is also transmittable. Sometimes this takes the form of a reinterpretation of events. Recently I was on a tour bus whose driver was the recipient of the truck driver's salute from an irritated motorist. Rather than express anger or insult, the driver suggested, "Look. That guy thinks I'm number one." As with all of life's adversities a working sense of humor is an invaluable defense. The situation may be critical but not serious.

    Optimism is highly correlated with success. What do you suppose a major league hitter is telling himself before he bats? Even the best of them make an out two-thirds of the time. Do you suppose that this statistic is weighing on him as he approaches the plate? Or is he likely to be imagining a happier result. People who never developed a belief in themselves, no matter their intrinsic talent, are unlikely to appear on major league rosters; they have long since been encouraged to pursue other occupations. The same might be said of successful salespeople. There is also a role here for recognizing that, since our pasts are largely stories of our own creation, we have the power of selective recall. Optimists are more likely to remember good outcomes while pessimists are discouraged by memories of failure. Optimists are also skilled at using the psychological defense of "reinterpretation" of events.

    On a hot day many years ago my the-middle school daughter Emily, one of the most optimistic people I know, was paddling with me in a cardboard boat race. As we began to take on water and the boat dissolved beneath us, I thought of the hours I had spent sealing and painting the fragile craft to prevent this outcome. Finally it sank and we became swimmers. Emily, seeing my disgust, said to me, "Oh Dad, doesn't that cool water feel good?"

    The school of "positive psychology" has demonstrated that optimism, like helplessness, can be learned. Using cognitive techniques and stress management Martin Seligman and his colleagues at the University of Pennsylvania have shown conclusively that pessimists can be taught to be optimists with beneficial effects on school and occupational success, even health.

    In one of the frequent examples of overlap between virtues, optimism is heavily dependent upon courage. Pessimism, like depression, is a "safe" position. Pessimists may be discouraged but they are seldom disappointed. If situations turn out badly, they expected as much. If things go better than predicted, they can only be pleasantly surprised. Optimists, on the other hand, risk disappointment, or worse yet, being taken advantage of and looking foolish. This is why we seek the middle ground, presumably occupied by true realists. Since we lack the power of foresight, however, we are all subject to surprise. So who would you rather spend your life with: those who brace themselves for the worst or those who anticipate the best?

    在我们这个充满了灾难和不公，时间与机会因人而异，且众生终将面临毁灭的世界上，是什么令一些人怀抱希望？除了慰藉性的宗教信仰，这种心态需要些许能从当下汲取愉悦与意义的心灵技巧。并非人人能为之。抑郁症在一生中的发生率约占人群的15-20%,而在任一时刻，我们当中约10%的人被悲伤和个人意义之丧失所困扰--这种情形将可以被我们正式确诊为抑郁症。

    既知天下之情形，又岂会惊讶于那么多人对未来抱有疑惑。最倾向于抑郁的悲观者们，大抵总是将自己视作"现实主义者";事情很糟，并越来越糟--看新闻时很难驳斥这种观点。可我们当下的个人幸福却大大地依赖于我们的期待。我们对未来的信念构成了自主履行的"预言":我们所获得的不是应得的，而是欲得的。这一事实最能生动地表现在我们与他者的交往中。那些我们带着信任与坦诚接近的人，往往会报之以李。反之，若我们以猜疑待人，他们也可能以牙还牙。

    怀抱希望绝非无私。相反，它是带着我们的私心，到乐观主义所谓"偶然的失望"中去冒险，从而让自己更频繁地在领悟希望之体验中受益。悲观者那惯常的面孔，好似一张抑郁的脸：总是挂着不满和不悦的蹙额。事实上，完美、悲观和灰心这三者，乃临床抑郁症之先兆及伴随症兆。这种逻辑在所难免：对自己及他者要求甚蕃者，势必在不完美的世界里感到不悦。正如大多数情绪（愤怒，焦虑，爱恋）一般，不悦亦会传染；它自我壮大并欲求共享。从前有两个女生被指派去打扫马厩，一人关注于她在铲的东西，另一人思忖道，"附近一定有匹小马。"

    在一定程度上，希望或缺乏希望，就像我们的很多态度一样，都是我们的经验之产物。心理学中有一个唤作"习得性无助"的领域，研究人们认为自己对所处境况无助时的后果。如果我们假设自己的付出与成果无关，那么我们就衍生出悲观和被动的观念。乐观要求我们相信：自己确能影响自己的命运。

    我们怎样应对生活中的挫败，很能测出我们怀抱怎样的希望。假如我们把一些恶果，视作人类爱莫能助的世界中之必然，我们还是能对自己将事情变好的能力保留信心。假如我们对不利事件反应为气馁无助和自责，那么很难想像我们还能改善境况。最终，我们那对改善事物的怀疑观固化为惯常的态度。或者如一位书店顾客所言，"我常常购买如何积极思考的书籍，而我后来想道，'它能起到什么作用？'"

    通常，要觉察出你面临的是一位悲观者还是乐观者，用不了多长时间。他人感受如何的最佳指示剂之一，是让我们唤起的心情。如果和一个人在一块儿，使我们感到气馁，那么可以公正地说，至少这是他们观点的部分折射。反之，乐观亦会传播。乐观有时需要对事件进行重新解释。最近，我坐旅行车，开车的司机就能接受一位脾气火爆的卡车司机的不敬。没有表达愤怒或侮辱，司机说道，"看。那家伙觉得我是第一。"面对一切生活中的不幸，足够的幽默感是无价的防御工事。事情也许很重要，但不严重。

    乐观与成功有高相关。你对棒球联合总会球员期待了什么，是不是在他击球前就告诉他了？即使是他们当中最佳的也有三分之二的出局。你觉得这个统计数据会让球员在接近本垒板时感到有压力吗？或许球员会憧憬一个更加的结果。那些从未对自己培养出一套信仰的人，无论其秉赋如何，不可能登上棒球联合总会的花名册；他们被鼓励去做别的事儿已久矣。成功的售货员大致是相同的。我们还要承认一个角色，由于我们的过往极大地编织了我们自己的世界，我们便拥有选择性回忆的权利。乐观者更喜欢忆起好的结果，而悲观者则被失败的记忆搞得气馁。乐观者长于使用对事件"重新解释"的心理防御。

    数年前一个炎热的日子里，我那上中学的十岁女儿艾米丽--我所认识的最乐观的人之一，和我在纸皮箱舟赛中划船。我们一上水面，小船就在我们身下分开了。我还能记得，为了预防这种状况，我曾花了数小时来密封和涂绘小船。最后它沉了，我们成了游泳赛手。艾米丽，看出我的厌烦，对我说，"喔，爸爸，那么棒的水不好吗？"

    "积极心理学"一派业已展现了乐观--正如无助感--是能够习得的。宾夕法尼亚大学的马汀·瑟李格曼（Martin Seligman）与其同事证实道，使用认知技巧和压力管理法，悲观者能够被训育为乐观者，益于学业和职业成就，甚至健康。

    在诸美德重叠的常见例子之一中，乐观很重地依赖于勇气。悲观，如同抑郁，是一席"安全"之地。悲观者也许气馁，但他们罕少失望。如果情况恶化，他们期待如此。如果事情优于预期，他们仅可能惬意一惊。乐观者，相反地，冒着失望或更严重的险，甚至被别人利用、视为夯货。这正是为何我们寻找中间组，他们大致是真正的现实主义者人群。我们固然缺乏预见力，但我们都会惊讶。那么，你更愿意与谁共度一生：是那些将自己束缚于致恶的人？还是那些期望最佳的人？