It's sometimes said (and I agree) that mastering a foreign language teaches a great deal about one's own. Similarly, I think, learning about other faiths can help us to understand ours, just as contrasts of shades and colors help us to see more clearly. Here's an example:
While, as with most Christian doctrines, groups and individuals have differed on this or that point, sometimes sharply, most Christians have historically believed that each human individual has — or, more accurately, is — a unique soul. This soul, once it begins to exist, is permanent. That is, it will not be destroyed. It constitutes the person's identity and, at death, continues to exist in a disembodied state until the resurrection.
Some Christians have disagreed at this stage, arguing that, at death, conscious individual existence temporarily ceases. It resumes, they say, with the resurrection of the body, because humans are identical, in a sense, with their bodies and because, therefore, consciousness and personality cannot exist without a physical basis. Prominent theories in both neuroscience and biblical studies have made this view especially attractive to certain recent Christian thinkers.
But, whichever theory one adopts, the soul that exists in the Resurrection is, according to mainstream Christianity, the same person who made moral decisions while in mortality, accepted or rejected Jesus and, in the end, will be accountable for her actions.
The mainstream Buddhist view — and, once again, Buddhists have differed on every point — is dramatically different. It's also rather difficult to grasp, and, as a non-specialist, I apologize if I misstate it in any way. I think, though, that I understand it in its fundamentals, and I believe that it offers a remarkably clear contrast to what I've identified as the mainstream Christian view.
According to typical Buddhist thinkers, there is no permanent individual soul. In fact, this teaching is sometimes called, quite expressively, the "no-Self" doctrine.
A person, on this view, is simply an aggregate of several transient "things" (which are themselves impermanent). Each individual mortal has a body, for instance, that changes constantly throughout life and will ultimately dissolve. Each person can be identified, too, as the center of a specific stream of sensations (pleasure and pain, for example) that come and go. None lasts very long, and they're constantly changing.
Likewise, humans are distinct from one another in their judgments and understandings, which are inevitably conditioned by their specific cultures. At any given moment, for example, I might judge that I'm sitting at a desk or talking with a friend or looking at a green object, while a different person may determine that she's standing on a mountaintop with a rival and looking at the blue sky.
A fourth area that distinguishes individual persons from one another is the collections of things that they will or desire, which, obviously, can differ wildly over time and between persons. And, finally, a fifth area in which persons are distinct is in their consciousness, based on their organs of perception (smell, taste, touch, seeing and hearing, to which Buddhist thinkers generally add a sixth sense, which is thinking or mental).
At this point, a Christian might exclaim that she, too, can and does accept all of these claims. Individual persons in Christian thought also have distinct bodies, sensations, understanding, wills and consciousness.
The difference is that, in Buddhism, there are only these things, in temporary, transitory bundles. There is, as the label says, "no Self" distinct from that ever changing stream of passing desires and perceptions.
It's difficult to see how Christian belief in a persisting person who bears moral accountability even after the death of the body can be reconciled with a Buddhist claim of "no-Self." Most Christian and Buddhist thinkers who've considered the matter seem to agree that no consensus on the issue is possible. Christian critics have even argued that Buddhist belief in reincarnation — the transmigration of souls, it's sometimes called — is itself impossible to harmonize with the idea that there is no permanent, continuing Self, and, therefore, no eternal person to bear blame under the laws of karma. But Buddhist scholars have defended the doctrine, and I'm in no position to judge the debate.
I can say, though, that Mormonism, with its radical doctrine of a persistent soul that existed before mortal life and can never be created or destroyed, offers an even starker contrast with Buddhist doctrine on this point than does mainstream Christianity.
Daniel C. Peterson is a professor of Islamic studies and Arabic at BYU, where he also serves as editor in chief of the Middle Eastern Texts Initiative. He is the founder of MormonScholarsTestify.org. He blogs daily at www.patheos.com/blogs/danpeterson/.