Methodical and Immutable

adjective

• Characterized by method and orderliness.
  • usage: "a methodical scholar"

• (a.) Arranged with regard to method; disposed in a suitable manner or in a manner to illustrate a subject or to facilitate practical observation; as, the methodical arrangement of arguments; a methodical treatise.
• (a.) Proceeding with regard to method; systematic.
• (a.) Of or pertaining to the ancient school of physicians called methodists.

adjective

• Not subject or susceptible to change or variation in form or quality or nature.
  • usage: "the view of that time was that all species were immutable, created by God"
  • synonyms: changeless