Any state is defined by two parameters: the Light and desire (Kli). In addition, when there is no Light and no desire for it (which is why the Light left), then what remains is a “record” (Reshimo) of both the Light and desire.
Suppose I had a desire and enjoyment within it, but now the state has changed: There is neither that previous Light nor the desire for it. In the new state I have a new desire, but how can I determine what Light to accept within it? I have a distinct desire that I sense right now, but I have not yet received the Light within it because the Light has to come from outside. In this case I use information (Reshimo) about the Light from my previous state and information about the desire from my current state.
Supppose I was in a restaurant yesterday where I enjoyed a meal costing 100 dollars. Today I come to the same restaurant with only 80 dollars and don’t know what to order with this money. Although I understand that I cannot order as much as I did yesterday, now I have to figure it out what to order based on what happened yesterday. I have to order a bit less and must determine precisely how much less. I remember the enjoyment (the Light) from yesterday, which is my only reference since enjoyment always comes from outside. There is only money (Kli) in my pocket and I know that today I have less of it.
Every spiritual state always contains information about desire (Reshimo de Aviut) and information about the Light that was clothed in the previous desire (Reshimo de Hitlabshut). Based on these two Reshimot it is always possible to understand what is occurring. Without these Reshimot (reminiscences) a person would lose his memory and reason. He would not know what happened a moment before and would not understand how to behave in the following moment.
We act only according to Reshimot. This data is built into us; we make all our comparisons and calculations based upon them.
From the 2nd part of the Daily Kabbalah Lesson 4/23/10, Preface to the Wisdom of Kabbalah