The notions of spirit and matter are very simple.
There is nothing startling or exceptional about them. We are material and spiritual.
Our existence is a double existence: on one side, a body with senses that perceive matter.
On the other, the spirit that conceives thinking and emotional processes-—two worlds running parallel, with varying emphasis on each at different times.
In some sense, we are more than just a simple amphibian, jumping from one environment into the other.
We do something far more complex: we live in two different existences simultaneously.
We live in one with our bodies, and in another through our minds, and the two of them mingle all the time.
Our assumption that existence is primarily physical, and that reality is that which is tangible, is not self-evident, natural, or inborn.
This sort of thinking (a spiritual phenomenon in itself) is based on cultural maxims that are taught to us.
From a very young age, we are taught that dreams, ideas, and thoughts are not real, and that What we say, think, and dream do not count.
In turn, we transmit to our children—not always in words—the notion that "reality" is that which can be seen and touched.
Our children get the message continuously, in both subtle and not so subtle ways: "If it does not exist in matter, it does not matter."
In our culture, if a small child breaks a cup, we scold him; if he cuts his finger, we are worried.
But if a child speaks of his dreams and imaginations, we dismiss them as unimportant, and even more—as unreal.
In this way, we are unintentionally, but continuously, brainwashed into thinking that the spiritual is not very real, and therefore we discount it in many ways.
This education has many evolutionary advantages, mostly to cats, cattle, or apes, who have to rely on their senses and not on their thoughts (if they have any).
Whether it is helpful in the long run for human beings is quite doubtful.
When we ignore or discount the intangible, we are misleading ourselves.
–Rabbi Adin Steinsaltz
From Simple Words, p. 56, by Rabbi Adin Steinsaltz