Soul Motives

A soul can be comprised of three motivations : Spirit (loyalty), Mind (knowledge and memory), and Heart (emotion). In a single being, these motives work together to create a personality and control its actions. Most, but not all, living creatures have a soul.
Soul motives are created, or more accurately, transformed, from a general soul motivation found throughout the universe. Creatures with souls have special organs, called haliments, used to convert this general motivation to each specific one it is capable of. Ones that are capable of producing one or more of these motivations are considered sentient, while beings that produce all three are considered sapient. Hominins, dragons, and other hyper-intelligent creatures are commonly sapients, while most other animals are simply sentient. Plants and extremely simple animals are generally neither, though there are a few exceptions.
The scientific study of soul motives and haliments is called Halimology.

Production

Each motive type has a corresponding haliment- an organ that transforms general soul motive into the more specific type. Spirit, Mind, and Heart haliments (if present) are all found in the being's brain.
How exactly the haliments work is still being researched. One theory claims that a being is born with all the soul motive it needs to last its lifetime, and the haliments simply swap some motive for another as needed. This explains why beings tend to maintain a similar personality throughout their life. However, it fails to consider exactly how general soul motive gets into the being in the first place. Halimologists generally uphold the second theory: general soul motive is taken in through a being's life, where the haliments then transform it into each motive. Here, it's the haliments responsible for one's personality, not the motive itself. This theory subdivides into two more: some proponents believe that general soul motive is taken in through breathing, and excess is exhaled through the same process. Others propose that haliments work as a kind of magnet, drawing motive directly into the organ, any bodily barriers being negligible. All motive would eventually turn into emotion, and would then transform into different types of energy related to the expressions of them (heat from blushing, sound from yelling, etc.). None of these theories have been proven to be completely true or false, and the true answer is likely in some combination.
What is certain, though, is that soul motive is attracted and bound to their respective haliments- not to each other. This creates a strange paradox: these related energies are more tethered to something material than motivational. As such, when a being dies, all of its soul motives are released from the body, and therefore, from each other.

Functions and Abilities

"Motives make a person that person. Just because you swear allegiance to the same king as another, does not mean you will experience the same feelings when you hear that the king has been killed."

- Melek Nadanian, professor at Maladeen University

It is common knowledge that the combination of soul motives create a being's personality. As mentioned above, a common debate among halimologists is whether this combination tends to mix or stay the same over time. Most people accept that it generally stays the same, though it can change slightly due to certain events in a being's life.
This means that when the being dies and its soul motives are dispersed, it is impossible to ressurect it with the same personality, if it gets one at all. Generally, ill-prepared ressurections result in a mindless zombie, and even skilled ones essentially give a newborn baby a mature body.
However, there are many ways to avoid this. The easiest is to simply not let the body die. With access to Vetris' powers through her favor, cults, or magical objects, it is easily done, but often for a limited amount of time. There are many ways to lose this access, and while some simply lose the immortality, others spell instant death. Those who are truly dedicated to immortality will only use this tactic while searching for the more permanent option: soul binding, where the soul is bound together in a way that makes the body unnecessary to retain consciousness. A soul-bound soul can wander the land as a clump of motive,  still interacting with the world even without their body (sound familiar? This is what ghosts are).

Common Misconceptions

Mortals have known about soul motives and haliments for thousands of years, but are far from understanding them completely. As new information is discovered and recorded, outdated information continues to be spread, and legends and myths are taken as fact. Following are a few common misconceptions held by the public and scientists alike.

The Heart Haliment

With its name, it's not surprising that many believe that the Heart haliment is located in one's heart. When the idea was first proposed by ancient human doctors, the Heart haliment was thought to be apart of the heart, and the Spirit haliment in the lungs. Modern science proved this to be untrue, but the names, and therefore the idea, stuck. Many folktales and myths still reference functions of the heart and lungs as related to emotion and spirit, respectively.

The General Soul Motive

In the Post-Divine Golden Age, it is easy to theorize that the general soul motive comes from Alnii's displaced motivation that fills the Ignis solar system. It handily explains the abundance of the motivation surrounding Vetrin (the site of the Divine Massacre), and lends a comforting credence that all mortals are extentions of Alnii's will.
However, this cannot be true for a simple, obvious reason: sentient and sapient beings have existed long before the Divine Massacre. There are records of mortal sapience even before the Human Age, making the theory impossible. Some dedicated cults or philosophers work around this by claiming Alnii artificially imbued his essence into living beings while alive, while less convincing ones claim that records of sapience before the Divine Massacre were forged. In reality, there are no well-supported theories about how or why general soul motive originated- even Seeraz and Vetris seem to be unaware of its origins.

Soul vs Spirit

Soul and spirit are often confused with one another. Spirit refers to one's loyalties: personal relationships, societal allegiances, and followed codes. It is one of three motives that make up a person's soul, which encompasses their entire personality.

Divines and Souls

Soul Control

Only 3 divines have direct control over soul motives: Mohhi-Shee, god of the Spirit; Seeraz, goddess of the Mind; and Dinzek, goddess of the Heart. They make up the Trihalad, and are often referenced or worshipped together during soul-binding or -cleansing ceremonies.
In some circles, Teero's community focus is connected to the general soul motive, but there is little evidence that he can control it in the same way the Trihalad members can.
Vetris does not control motives at all; her ability to control living beings stems from material manipulation. Despite this, her associations with medicine make her extremely relevant to haliments and their functions, making her worship necessary even for those who reject bodily needs.

Divine Soul Makeup

This article is mainly in reference to mortals, of course. Divine souls are a bit different.

• The five main gods were once mortal, and as such must stay alive through combined use of soul binding and immortality.
• Many daemons don't seem to naturally have a soul, or at least not a sapient one, and do their jobs mechanically. A few were created with souls, but there is no telling how similar they are to a mortal's. On the other hand, ones like Savet are actually mortal souls, transplanted into the force of nature.
• Astrolons clearly have souls, but they seem to be more complex than a mortal's. Instead of being seperate functions, Alnii's motives seem to be intricately woven together, much more so than a soul binding, as they almost form a new kind of super-motivation. Halimologists work closely with clerics and paladins to study Alnii's soul motives, in hopes to create more effective and available soul binding.