Saandism, the traditional religion of Jute, combines tenets of science, particularly astronomy and math, curiosity and philosophy with greenism and communitarianism. (See also eco-communalism)
You can read about its origin in the prehistory factbook.
Name and central philosophy
The name "Saandism" originates in the native Jutean (factbook coming soon) word Saandi, referring to a state of contentment with life, where nothing bothers you anymore, and you don't feel the need to change anything anymore. This concept has been a key part of the mentality of Jute since anyone can remember. The full name of the religion, also makes clear how this should be achieved, namely na trikki u mohomo harandi, translating to "through numbers and harmony with wildlife", meaning keeping an interest in the sciences, especially math while taking care of the land around you as well, thereby creating a balanced life in both the immaterial as well as the material world.
Tenets and daily life
Sacrifices are not encouraged, instead a self-reflective prayer twice a day is one of the most important aspects of it. In the morning, a minute of commemoration for everything the nature is providing them. During this, everyone is also supposed to think about what they could do to better themselves and society. In the evening, a review of their day was to take place, what you achieved today and what plans you have for tomorrow.
The oldest rule, which initiated discussions on finding a way to respectably live with each other and with nature, was to plant a new tree for every one destroyed, after some trees had to be cut down to make rooms for new farms. Over time, this developed in a somewhat organized religion, complete with a "rulebook", where the elders and others wrote down the guidelines on how to achieve the achieved state of saandi that soon was written down.
Important to note is that these weren't strictly "rules", more guidelines, that weren't forcibly enforced. Not following them didn't earn you any punishments, worldly or otherwise (the concept of "hell" was unknown and only later importer by missioning Christians) but would eventually lead to an alienation from society, and finally, ostracism, which was seen as punishing enough.
Not that the book required any overly specific things from you, or didn't allow for any leeway. It contained more general moral guidelines on how to live with society and how society benefits the individual, guidelines how to respectfully use wildlife, natural resources. Any details were to be talked and agreed upon with other members of the community. Elder people could also often explain certain parts of it, and help you try to achieve the desired mental state, which involved continued study of philosophy and science, which at the beginning mostly meant mathematics.
The importance of numbers
After all, as the aforementioned prehistory factbook will tell you, numbers were introduced already very early on to the existing philosophy, and quickly became an object of interest for many people, with mathematical puzzles soon establishing themselves as an esteemed and popular pastime. The discovery of prime numbers only furthered the admiration Ancient Juteans had for them. Those were seen as "divine" numbers because of their special abilities, as at first "divinity" was seen as a state of high "purity" and "originality", of which everything else was supposed to have developed. Even though that view changed a bit over the time, numbers are still hold in high regard, thought of as part of the logical half of the immaterial world, together with philosophical musings, with artistic endeavors, especially those more abstract and less realistic on the other side, similar to Linkmandalas.
Understanding the imperfection of the material world
When the telescope was first invented, scientists of Jute first noticed how the moon, previously thought of an example of an "perfect" material object, "pure" in a way similar to prime numbers, actually was scarred all over the surface, with some larger, some smaller holes. This lead to the development of the tenet "Do not strive to be perfect, for it is neither possible or reasonable. The beauty and goodness of things comes from their imperfection., meaning it is not the purpose of things of the material world to be as flawless as things of the immaterial one. The state of "purity" the prime numbers have can't be achieved, and neither should it, as it would destroy all things that make the material world worth living.