There is a lot of confusion about the term "rationalism." What is a rationalist? The differences between rationalists and non-rationalists fall into three categories:
• KNOWLEDGE - Considering it as legitimately obtained ourselves via our own reasoning and senses, and considering that it should preferably be based upon evidence/reason rather than faith, especially for far-fetched claims.
• NATURE - Valuing a naturalistic rather than supernatural interpretation of events, and perceiving a consistent natural order over history, past and future.
• THE SERVICE OF GOD - Understanding the role of mitzvos and one’s religious life in general as furthering intellectual/moral goals for the individual and society rather than the mechanistic manipulation of spiritual or celestial forces.
(This primarily refers the medieval rationalists of Sefarad, in contrast to the non-rationalist approach that subsequently emerged.)