I've noticed that many English translations of the old Pali and Sanskrit texts use the words "greed" and "desire" interchangeably, and I want to come back to that in a bit. But first let's look at the English words.
The English word "greed" usually is defined as attempting to possess more than one needs or deserves, especially at the expense of others. We're taught from childhood that we shouldn't be greedy.
To "desire," however, is simply to want something very much. Our culture doesn't attach a moral judgment to desire. On the contrary, desire in the romantic sense is celebrated in music, art and literature.
A desire for material possessions also is encouraged, and not just through advertising. People who have earned wealth and the possessions that go with it are held up as role models. The old Calvinist notion that wealth accrues to people who are worthy of it still clanks about in our collective cultural psyche and conditions how we think about wealth. Desiring things isn't "greedy" if we feel we deserve those things.
From a Buddhist perspective, however, the distinction between greed and desire is artificial. To want passionately is a hindrance and a poison, whether one "deserves" the thing wanted or not.
Sanskrit and Pali
In Buddhism, more than one Pali or Sanskrit word is translated as "greed" or "desire." When we speak of the greed of the Three Poisons, the word for "greed" is lobha. This is an attraction to something that we think will gratify us.
As I understand it, greed is fixating on a thing we think we need to make us happy. For example, if we see a pair of shoes we think we must have, even though we have a closet full of perfectly good shoes, that is greed. And, of course, if we buy the shoes we may enjoy them for a time, but soon enough we forget the shoes and want something else.
The word translated "greed" or "desire" in the Five Hindrances is kamacchanda (Pali) or abhidya (Sanskrit), which refers to sensual desire. This kind of desire is a hindrance to the mental concentration one needs to realize enlightenment.
The Second Noble Truth teaches that trishna (Sanskrit) or tanha (Pali) -- thirst or craving -- is the cause of stress or suffering (dukkha).
Related to greed is upadana, or clinging. More specifically, upadana are attachments that cause us to remain wandering in samsara, bound to birth and rebirth. There are four main types of upadana -- attachment to senses, attachment to views, attachment to rites and rituals, and attachment to a belief in a permanent self.
The Danger of Desire
Because our culture implicitly values desire, we are unprepared for its dangers.
As I write this, the world is reeling from a financial meltdown, and entire industries are on the edge of collapse. The crisis has many causes, but a big one is that a great many people made a great many very bad decisions because they got greedy.
But because our culture looks to money-makers as heroes -- and money makers believe themselves to be wise and virtuous -- we don't see the destructive force of desire until it is too late.
The Trap of Consumerism
Much of the world's economy is fueled by desire and consumption. Because people buy things, things must be manufactured and marketed, which gives people jobs so they have money to buy things. If people stop buying things, there is less demand, and people are laid off their jobs.
Corporations that make consumer goods spend fortunes developing new products and persuading consumers through advertising that they must have these new products. Thus greed grows the economy, but as we see from the financial crisis, greed also can destroy it.
How does a lay Buddhist practice Buddhism in a culture fueled by desire? Even if we are moderate in our own wants, a great many of us depend on other people buying stuff they don't need for our jobs. Is this "right livelihood"?
Manufacturers cut the cost of products by underpaying and exploiting workers, or by cutting corners needed to protect the environment. A more responsible company may not be able to compete with an irresponsible one. As consumers, what do we do about this? It's not always an easy question to answer.
A Middle Way?
To live is to want. When we are hungry, we want food. When we are tired, we want rest. We want the company of friends and loved ones. There is even the paradox of wanting enlightenment. Buddhism doesn't ask us to renounce companionship or the things we need to live.
The challenge is to distinguish between what is wholesome -- taking care of our physical and psychological needs -- and what is unwholesome. And this takes us back to the Three Poisons and the Five Hindrances.
We don't have to run screaming from all of life's pleasures. As practice matures, we learn to distinguish between the wholesome and the unwholesome -- what supports our practice and what hinders it. This in itself is practice.
Certainly, Buddhism does not teach that there is anything wrong with working to earn money. Monastics give up material possession, but laypeople do not. The challenge is to live in a material culture without getting snared by it.
It isn't easy, and we all stumble, but with practice, desire loses its power to jerk us around.