Spinoza distinguishes between three levels of knowledge and describes how we can move from the lowest to the highest. We begin with the things most familiar to us, and says Spinoza, “the more we understand individual things the more we understand God.” By refining our knowledge of things, we can move from (1) imagination, to (2) reason, and finally to (3) intuition.

At the level of imagination our ideas are derived from sensation,as when we see another person. Here our ideas are very concrete and specific, they are vague and inadequate, for we know things as the affected our senses — I know that I see a person, but as yet I do not know simply by looking what this person’s essential nature is. I can form a general idea, such as human, by seeing several people, and the ideas I form from experience are useful for daily life, but they do not give me true knowledge.

the second level of knowledge goes beyond imagination to reason. this is scientific knowledge. everyone can participate in this kind of knowledge because it is made possible by a sharing in the attributes of substance, in God’s thought and extension. There is in humanity what is in all things, and since one of these common properties is mind, the human mind shares in the mind that orders things. At this level a person’s mind can rise above immediate and particular things  and deal with abstract ideas, as it does in mathematics and physics. At this level knowledge is adequate and true. If we ask Spinoza how we know that these ideas of reason and science are true, he replies in effect that truth validates itself, for “he who has a true idea knows at the same time that he has a true idea, nor can he doubt concerning the truth of the things.”

The third and highest level of knowledge is intuition. Through intuition we can grasp the whole system of nature. At this level we can understand the particular things we encountered on the first level in a new way, for at the first level we saw other bodies in a disconnected way, and now we see them as part of the whole scheme. This kind of knowing “proceeds from an adequate knowledge of the essence of things.” When we reach this level we become more and more conscious of God and hence “more perfect and blessed,” for through this vision we grasp the whole system of Nature and see our place in it, giving us an intellectual fascination with the full order of Nature, of God.