Okay, these are two of the four Brahma Viharas. Rosemary mentions it them when she teaches the Sympathetic Joy meditation in the normal retreat. In the Pali language, the four Brahma Viharas, or Divine Abodes, are very good mental states. In Pali, they are called Metta, Karuna, Mudita, and Upekkha. Now, generally, the translation is that Metta means Lovingkindness, Karuna means Compassion, Mudita means Sypmathetic Joy and Upekkha means Equanimity.
Those are the normal translations. We don't agree with them. Our way of understanding the word Metta is that it includes what we call Compassion/Lovingkindness, the two together. At the same time, though, the word Karuna means Compassion. Okay, this is odd. We have Compassion/Lovingkindness together, then we have Compassion as the second one. Why is it different here? Why is Compassion in the first one, and then in the second by itself? When you look at the Compassion/Lovingkindness wish that we encourage, first, we wish for no more problems, no more difficulties; then, we wish for peace of mind or deep happiness. So it has these two parts.
Now, the first part: wishing for no more difficulties, no more Dukkha. Wouldn't that be nice in itself? Wouldn't that just be lovely if no one on the whole planet was starving anymore? Wouldn't it be lovely if we didn't have sickness and decay and all sorts of things? Wouldn't that be lovely by itself? Yes, this is why Compassion can stand by itself. It would be lovely just to have no more pain. That's enough in the world. If that was done, that would be wonderful. So Compassion can stand by itself as the word Karuna.
Why, then, do I say Metta is a combination of Compassion and Lovingkindness? The way that we use the word, Lovingkindness is a wish for happiness. Now, if I sit down and just wish people happiness, why would I do that? Why on earth would I wish anybody happiness? Don't I have to understand Dukkha exists? Don't I have to understand that people actually have pain? They have Dukkha. They have problems. Why else would I wish them happiness? I must actually have Compassion as a base first before I can wish for happiness. I can't wish happiness by itself; it's impossible. I must understand unhappiness and that I don't want the unhappiness anymore. That's what the wish for happiness is.
That's why we say the word Metta includes both Compassion and Lovingkindness together. Now, we go a little bit farther when we define it in full. We say, then, in both Metta and Karuna, that they need to have the support of Equanimity. So we're not even separating Equanimity totally; we actually want to stick it in with Compassion and with Compassion/Lovingkindness so that they're both strong; we combine that one as well.
The reason that a lot of other Buddhist's say that Metta means Lovingkindess is, perhaps, that they don't fully understand Compassion in the practice. They may not understand that the Four Noble Truths are telling us to look at Dukkha. The Four Noble Truths push us to wish to end Dukkha. If we're actually working with the Four Noble Truths, we're working on Compassion nonstop. A lot of other Buddhists don't actually understand that, because they don't understand Dukkha enough or the Four Noble Truths. That's one reason.
A second reason can be that the person's definition of Lovingkindness is different to ours, and that's important, too. Some people might use a definition which looks very much like ours, including Compassion and Lovingkindness but thinking that "Lovingkindness" means both of them together, anyhow. That could be another reason why some of them use that as the translation. In those cases, it's good to talk to the teacher and be sure what they mean. Ask them what they mean with the word Metta and with the word Lovingkindness. However, it is true that a lot of them simply don't understand the importance of Compassion in the practice. They immediately go to the wish for happiness which gets them feeling a bit high. But that's not what we're wanting; we're wanting deep Wisdom.