What is love? Seriously, though, what is it? What is love?
爱是什么？说真的，它到底是什么？爱是什么呢？
A verb? A noun? A universal truth? An ideal?
一个动词？一个名词？普遍的真理？一个理想概念？
A common thread of all religions? A cult? A neurological phenomenon?
宗教信仰的共同点？一种狂热的崇拜？一种神经学现象？
There's no shortage of answers. Some are all-encompassing.
这个问题可以有很多很多答案，一些答案很共通。
It conquers all. It's all you need. It's all there is.
它凌驾于一切之上，它是你唯一渴望的东西，它就是爱。
These are all comparisons, though, ways of defining it by contrast,
话虽如此，这些都是用类比的方法去诠释爱的，
by saying it's more important than all other things, but is it?
与世间万物相比，爱尤为重要，但真的是这样吗？
Sure, love matters more than your standard turkey sandwich, but does it matter more than shelter?
当然， 爱远比你普通的火鸡三明治来得重要，但它是否敌得过居住的房子？
Or sanity? Or an exceptional turkey sandwich?
或者能否打败理智？亦或是一份豪华火鸡三明治呢？
No matter your answer, you're just ranking it, not defining it.
不论你的答案是什么，你只是进行了排名，而非定义它。
Another challenge to defining love is we often try to do so while falling into it or out of it.
定义爱的另一个难题就在于我们经常在自己坠入爱河时或在失去爱的时候去定义爱。
Would you trust someone who just won the lottery to accurately define the concept of currency?
你会相信一个刚赢了彩票的人能精确地定义金钱吗？
Or, I don't know, ask a guy to define bears while he's fending them off?
或者，再问一位刚刚逃脱了狗熊追击的哥们，熊到底可不可怕？
Or is romance not like winning the lottery? Are break ups not like bear attacks? Bad comparisons?
再或者，浪漫是不是就像中彩票一样？被熊袭击跟失恋的感觉一样吗？不恰当的比喻对吗？
That's my point. I'm not thinking right because I'm in love, so ha!
这就是我的意思。我无法理性地思考，因为我在谈恋爱，所以，哈哈！
Taking a step back, or taking a cold shower, whatever,
退一步讲，或者冷静一下，无论如何，
love is potentially the most intensely thought about thing in all of human history.
在人类历史长河中，爱可能是被思考最多的主题。
And despite centuries upon centuries of obsession, it still overwhelms us.
尽管人类迷恋爱情已有成千上万年，爱情还是能轻而易举地让人沦陷。
Some say it's a feeling, a magical emotion, a feeling for someone like you've never felt before.
有人说爱是种感觉，一种神奇的情感，一种从未有过的感觉--直到你遇到了那个人。
But feelings are fluid, not very concrete foundation for a definition.
但是这感觉捉摸不定，不能作为定义的实据。
Sometimes you hate the person you love.
有时候你还会讨厌你爱的那个人呢。
Plus, come on, you've felt feelings like it before, sort of in miniature.
再说了，拜托，或多或少，你总会有这种感觉。
Your relationships with your family shape your relationships with partners.
你和家人的关系映射出了你与伴侣的关系。
And your love for your partner may be in its own dynamic relationship,
而你对伴侣的爱，可能也与你对父母和兄弟姐妹的爱相互影响，
healthy or totally weird, with the love of your parents and siblings.
这些情感有着某种或正常或奇怪的复杂联系。
Love is also a set of behaviors we associate with the feeling:
爱情同样是一系列由情感支配的行为：
Holding hands, kissing, hugging, public displays of affection, dating, marriage, having kids, or just sex.
牵手，亲吻，拥抱，秀恩爱，约会，结婚，生儿育女，或只是性爱。

But these loving actions can be subjective or culturally relative.
但这些行为可以是主观的，也可以是与文化背景相关的。
You may love or be someone who can't have kids or doesn't want to, who believes in marriage but also in divorce,
你可能会爱上一个不能生育或不想生育的人，一个离婚但是也相信婚姻的人，
who's from a culture where people don't really date the way we think of dating,
一个有着和我们认为的不一样约会文化的人，
or who just doesn't want to make out on the bus.
或者只是一个不想在公车上亲热的人。
But if love is a thing that we can define, then how can it mean opposite things for so many people?
但是如果我们能够定义爱情，那它怎么对于不同的人来说意味着那么多不同的事？
So, maybe love's just all in your head,
所以，也许爱情只存在于每个人的心里，
a personal mystery winding through your neural pathways and lighting up pleasing, natural rewards in your nervous system.
奇妙的电流从你的神经里窜过，然后触发了你的神经系统。
Perhaps these rewards are addictive.
作为奖励，你得到了一种愉悦的自然反应。
Perhaps love is a temporary or permanent addiction to a person, just like a person can be addicted to a drug.
或许这些甜头是令人欲罢不能的，爱也可能是一个短暂的，亦或是永远的瘾，就像一个人可以对毒品上瘾。
I don't mean to be edgy like some pop song.
像一些流行乐中唱的一样，我不是故意弄噱头激怒你。
Evidence shows that chemicals in your brain stimulated by another person can make you develop a habit for that person.
证据表明，你脑内的化学物质被另外一个人激发，这些物质会让你对那个人产生依赖。
The person comes to satisfy a physiological craving, and you want more.
而如果那个人回应了你生理上的反应，你会接着想要更多。
But then sometimes, slowly or suddenly, you don't.
但是有时候，慢慢地或者突然间，你厌烦了。
You've fallen out of love, become unaddicted, for a spell. What happened?
你从爱里走出来了，不再有瘾了，暂时地。然后发生了什么？
Does one develop a tolerance or hit a limit?
到底一个人是要提高宽容度还是挑战底线？
Why do some lovers stay addicted to each other their entire lives?
为什么有的恋人甘之如饴，直到生命结束？
Perhaps to create new lives, to proliferate their species?
或许只是为了生一个宝宝，为了繁衍子嗣？
Maybe love is just human DNA's optimal method for bringing about its own replication.
或许爱只是人类DNA选择的一种保证自己存活方式。
There are evolutionary arguments regarding every human mating behavior,
有太多的进化论观点，从人类的交配行为，
from how we display ourselves to potential mates, to how we treat each other in relationships, to how we raise kids.
到我们如何求偶，到我们如何在恋爱中对待对方，再到我们如何教养孩子。
Thus, some argue that the feeling you think you feel in your soul is just biology's way to make you continue our species.
因此，有些人说那种你认为在你灵魂深处的感觉只是个生物学的途径，为的是让你延续种族。
Nature has selected you to have crushes on hotties,
自然选择了你，去爱上那个辣妹，
just like it makes monkeys have crushes on hot monkeys, and biology marches on.
就像它让猴子爱上迷人的猴子，然后种族得以延续。
But is that all love is?
但是这难道就是爱的全部吗？
Or, perhaps worse, is it just a construct,
或者，更糟的是，那会不会只是一种构想，
some fake concept we all convince each other to try to live up to for a fake sense of purpose?
一种我们为了一个目的的虚假意义而说服彼此去实践的一个假的概念？
Maybe it is a construct, but let's be more precise about what a construct is because love is constructed from reality:
它可能是一个构想，但是让我们对何为构想更精准些，因为爱是从现实建构的。
Our experiences, feelings, brain chemistry, cultural expectations, our lives.
我们的经历，感觉，脑袋里的化学反应，文化观，我们的生活。
And this edifice can be viewed through countless dimensions:
以上这些显而易见的体系，可以用无数的标准来衡量：
scientific, emotional, historical, spiritual, legal, or just personal.
从科学层面，情感层面，历史层面，精神层面，合法性或者只是个人看法。
If no two people are the same, no two people's love is the same either.
假如每个人都是独一无二的，也就没有一模一样的爱。
So, in every loving relationship, there's a lot to talk about
所以，在每段恋爱中，总是有许多可以谈论的话题，
and partners should be open to that, or the relationship probably won't last.
恋人们需要彼此接受这一点，否则这段恋情不会持久。
Love is always up for discussion and, sure, under construction.
爱是一个永恒的话题，没错，在臆想之下。
So, if we can't define it, that's a good sign.
所以，即使我们不能定义爱情，也不代表这是件坏事。
It means we're all still making it. Wait, I didn't mean, you know what I meant.
这意味着我们仍然在做它。等等，我并不是那个意思，你知道我的意思。