Spiritual science does not merely signify the acquisition of knowledge; it signifies most pre-eminently an education, a self-education of our souls. We make ourselves different; we have other interests. When a man imbues himself with spiritual science, the habits of attention for this or for that subject which he developed during previous years, alter. What interested him before, interests him no longer; that which had no interest for him previously, now begins to interest him in the highest degree.
One ought not simply to say that only a person who has gone through esoteric development can attain to a connection with the spiritual world; esotericism does not begin with occult development. The moment we make any link with spiritual science with our whole heart, esotericism has already begun; our souls begin at once to be transformed. There then begins in us something resembling what would arise, let us say, in a being who had previously only been able to see light and darkness, and who then through a special and different organisation of the eyes, begins to see colors. The whole world would appear different to such a being. We need only observe it, we need only realise it, and we shall soon see that the whole world begins to have a different aspect when we have for a time gone through the self-education we can get in a spiritual science circle.
Source: Rudolf Steiner – GA 136 – The Spiritual Beings in the Heavenly Bodies and in the Kingdoms of Nature: Lecture 1 – Helsinki, 3rd April 1912