One thing is the same in all three worlds and that is logical thinking

No genuine teacher of Rosicrucianism will guide the pupil to the higher stages if the student has no aptitude for what this first stage demands. It requires the student to develop a thinking that is thoroughly sensible and logical. This is necessary if the pupil is not to lose the ground under his feet at the higher stages. From the start it must be made clear that, unless all inclination towards fantasy and illusion is overcome, it is all too easy to fall into error when striving to enter spiritual realms. A person who is inclined to see things in a fanciful or unreal light is of no use to the spiritual world.

That is one reason; another is that though a person is born from the astral world, that is from the spiritual world next to the physical, as much as he is born from the physical world, what he experiences there is completely different from anything seen with physical sight or heard with physical ears. One thing, however, is the same in all three worlds—in the physical, the astral or spiritual, and the devachanic world—and that is logical thinking. It is precisely because it is the same in all three worlds that it can be learned already in the physical world, and thus provide a firm support when we enter the other worlds. If one’s thoughts are like will-o-the-wisps so that no distinction is made between what is merely depicted and reality, then one is not qualified to rise into higher worlds. 

Source: Rudolf Steiner – GA 55 – Supersensible Knowledge – XI. Who are the Rosicrucians? – 14 March 1907, Berlin

https://rsarchive.org/Lectures/GA055/English/AP1987/19070314p01.html

Translated by Rita Stebbing