404, 6. After the "wedding," the first union is with a desire for knowing, which gives rise to a desire for what is true. "After the wedding" means our state after birth, beginning with a state of ignorance and continuing through a state of discernment all the way to a state of wisdom. The first state, that of pure ignorance, is not what I mean by the wedding, since our discernment has no thought at that point, only a faint impulse of our love or volition. This state is a prelude to the wedding. It is recognized that there is a desire for knowing in the second state, the one characteristic of our childhood. This is what enables little ones to learn to talk and to read and then gradually to learn the kinds of things that constitute discernment. We cannot doubt that love--which is a matter of volition--is doing this, since unless love or volition were the driving force, it would not happen.
Everyone who reflects rationally on experience realizes that after we are born we all have a desire for knowing and that this is the basis of our learning the kinds of things that lead gradually to the formation, development, and attainment of discernment. We can also see that this gives rise to a desire for what is true, since once we have become discerning because of our desire for knowing, we are motivated not so much by a desire for knowing as by a desire for systematic thinking and drawing conclusions about subjects that we love--economics, perhaps, or civic or moral issues. When this desire rises all the way to spiritual concerns, it becomes a desire for spiritual truth. We can see that the first step or prelude was a desire for knowing from the fact that a desire for what is true is a higher level of the desire for knowing. This is because being moved by truths comes from wanting to know them because of our desire and then absorbing them with passionate delight when we find them.
7. The second union is with a desire for discerning, which gives rise to a sense of what is true. Anyone can see this who is willing to explore the matter with some rational insight. Rational insight shows that a desire for what is true and a sense of what is true are two abilities enjoyed by our discernment, abilities that merge into one for some people but not for others. They merge into one for people who want to grasp what is true intelligently, but not for people who want only to know about what is true. We can also see that our engagement in the grasp of truth depends on our desire to understand it. If you take away the desire to understand what is true, there will be no grasp of what is true; while if you grant the desire to understand what is true, there will be a grasp of it proportional to the intensity of the desire. This is because no one of sound reason ever lacks a sense of what is true as long as the desire to understand it is present. I have already explained  that everyone has the ability to discern what is true that we call rationality.
8. The third union is with a desire to see what is true, which gives rise to thought. A desire for knowing is one thing; a desire for discerning is another thing; and a desire to see something is something else again. We can also say that a desire for what is true is one thing; a grasp of what is true is another thing; and thinking is something else again. If people have no clear grasp of the workings of the mind, they can see this only dimly; but it is clear for people who can grasp them clearly. The reason people see this only dimly if they cannot grasp the workings of the mind clearly is that these activities are all happening at the same time in the thinking of people who are caught up in a desire for what is true and in a grasp of what is true; and when they happen at the same time, they cannot be distinguished from each other. We are engaged in conscious thinking when our spirit is thinking in the body. This is the case especially when we are in the company of others. However, when we are engaged in a desire for discerning and come thereby into a grasp of what is true, then we are engaged in the thinking of our spirit. This is meditation, which does indeed reach down into our physical thought, but subtly. It is on a higher level and looks into thought processes based on memory as below it, since it is using them either for decision or for support. The actual desire for what is true, though, is felt only as an impulse of our volition stemming from a kind of pleasure. This resides within reflection like its life, and draws little attention.
We may conclude from all this that these three abilities--the desire for what is true, the grasp of what is true, and thought--follow in sequence from love and are nowhere manifest but in our discernment. When love enters discernment (which happens when the union is realized), then it first gives rise to the desire for what is true, then to the desire to understand what it knows, and finally to a desire to see in physical thought whatever it understands. Thinking is actually nothing but an inner sight. Thinking does happen first because it is a function of our earthly mind; but when it comes to thinking on the basis of a grasp of what is true because of a desire for what is true, that happens last. That kind of thinking is the thinking of wisdom, while the other is thinking on the basis of memory, using the sight of our earthly mind.
All the workings of love or volition outside our discernment are based not on desires for what is true but on desires for what is good.