There are 4 states / realms for Spiritual Strength.
Mortal State / Mortal Realm: Ranging from 1st to 7th ranked Alchemists.
Soul State / Spirit Realm: Every 8th ranked Alchemist. Divided into 3 stages: inital, mid and late.
Heavenly State / Heaven Realm: This is the level of 9th ranked Alchemists. In this stage, the soul can become solid and as strong as the physical body. Divided into 4 stages: Initial, Intermediate, Advanced, and Perfect. At Perfect Heavenly State, the soul could span for 10 thousand of miles.
Di State/ God Realm: The soul can cover hundred thousands of miles. It is relatively easier to achieve than making a Di Rank Pill or becoming a Dou God.