The mind denies seeing the things directly, to see them in their presence without the word and the symbol.
You for instance say, that the sky is blue. The one who hears it, interprets it from the conception he has about blue and reproduces it to you in his own code. In that way we live in symbols, and dreams are a part of this symbolic process. We are not able to perceive directly and immediate without the symbols, the words, the prejudices and the conclusions.
The reason for this is clear enough: It is a part of the self-centred becoming something, the will to power with its defence, resistance, escape and anxiety, and where you shut yourself away from life, are getting absent in evaluations and analyses, and where emptiness and loss slide in between, create reflections, displacement and darkness.
In this unreal state reality can only communicate itself symbolic.
The symbol is a telescopying, a representing quintessence of the wholeness, the information-quantities, and the greater clarity, which is connected with reality and presence, but which the absence can´t contain, because it splits, shuts itself inside, or shuts itself away from.