Soulmate (or soul mate) is a term used to designate someone with whom one has a feeling of deep and natural affinity, friendship, love, intimacy, sexuality, and/or compatibility. A related concept is that of the twin flame or twin soul – thought to be the eventual soulmate, the one and only other half of one's soul, for which all souls are driven to find and join. However, not everyone who uses these terms carries such mystical connotations; they are sometimes used only as an expression of strong emotional feeling for someone.

Like many spiritual beliefs, the concepts of twin spirits or soul mates are predicated upon deep spiritual experiences for which there are actually no adequate words. We use metaphors to describe such experiences until the experiences become so commonplace that new words evolve to more accurately describe our experiences or the metaphors stick like glue and we come to accept the metaphor as a literal description when in fact it may still fall short of being a valid description of our experience.

While it is definitely true that many of us have experiences in which we recognize another soul with whom we are intimately connected in some inexplicable way, perhaps we should examine the metaphors we use to describe these experiences to shed some light on what may really be going on. Metaphors are used to apply past experiences, which we recognize to new experiences, which we have no proper concepts for. Without clearly understood concepts we can have no words, which exactly describe our new experiences, which is why we must resort to metaphors. But a metaphor is an approximate likeness between two experiences which will typically accurately describe our familiar experience but which will provide only a reasonably close ‘as-if' description of our new experience.

So when we meet someone with whom we feel we can share a common past or destiny we search for a way to explain this feeling and our culture has developed the concepts of soul mates and twin spirits to accommodate our basic need for words to describe how we feel.

The metaphors of soul mates and twin spirits come from our actual experiences with having partners in life, our mates, or having known someone with a twin, a biological condition. Both indicate a degree of relatedness that is over and above the way we appear to be related to most other people in our lives and that is the essence of what we are trying to express when we find someone with whom we communicate on a very deep level of our souls.

However, there are considerations, which may make the concepts of soul mates and spiritual twins valid metaphors for our experiences of being thoroughly related with another person's soul. Perhaps our souls have somehow divided themselves and our souls have thereby created an independent soul mate. This is one explanation, which would make soul mates or twin spirits a reasonably valid metaphor for the experience of meeting a very special person.