Good Afternoon!
Today we have yet another lesson concerning cause and effect that is reversed from the usual way in which we think in this world. The reason we see no neutral things "out there" in the world is because we first and foremost do not think or see any neutral thoughts in our mind. As the lesson says, this is difficult for us to understand but we must learn this. Notice the word "must" which of course is pretty straightforward.
The sentence that stands out to me in this lesson is found in paragraph 3, sentence 3, which says "That is because you are unaware as yet of any thought that is really true, and therefore really happy." There is resistence that comes up for me when I read this. My ego gets bent out of shape with this statement. It seems as if I should really know something that is true, shouldn't I? It undermines my whole thought system and makes me feel like I'm on shaky ground here. That is because I really am on shaky ground, here at the level of form - in this world. If I am reliant on my ego to show me the truth, then I am in trouble. 
I am reminded of a wonderful line in the text of A Course in Miracles that speaks to me today and that is: The ego's whole continuance depends on its belief you cannot learn this course. T-22.III.2:1
I can learn this course.
Joan