Answer: We call it the upper because it is above our properties. Our properties are the properties of receiving, and therefore, we are very dependent on our egoistic desires and their fulfillment.
And the upper world, these are properties that consist of the desire to give, fulfill, love, and nourish others. Since they (the properties) are independent, free in their essence, they are called upper.
In addition, they are closer to the Creator in their attributes. He is absolute bestowal and love. And therefore, everything that is closer to Him, we define as above us, i.e., closer to the root cause.
Question: Speaking of the upper world, we often call it spiritual. What does the word “spiritual” mean?
Answer: The upper world is called spiritual because it is not material.
Question: Is there a difference between the terms “spiritual world” and “upper world”?
Answer: No, these are common, unspecified names.
Question: What is spiritual attainment?
Answer: The comprehension of nature in the quality of bestowal, equal to the Creator, is called spiritual attainment.
From KabTV’s “Fundamentals of Kabbalah,” 6/17/19