The inherent unreasonability of happiness

From the last paragraph of 4:417 to the end of the paragraph that runs into 4:419, Kant speaks on reason and happiness. He begins by saying that “…the concept of happiness is so indeterminate…” that one can never say with determination what they actually wish or want for themselves, because all of “…the elements that belong to the concept of happiness…” must be borrowed from experience. He goes on to list some ways in which things that people think may make them happy might have unintended consequences, implying that omniscience would be required to know with certainty what would make someone happy. To BE happy, then, one cannot act on any principles that can be objectively reasoned towards, but only on experience with what has generally advanced well-being in the past. Further, no actions can be said to be a necessary step towards happiness, but must instead be considered as reasonable councils. In fact, nothing can be said to be necessary for happiness, because happiness in itself is not able to be reasoned to. Reason lets you know how you may be able to act or conduct yourself in such a way that you might be able to achieve something that you THINK will allow you to achieve happiness, but once you achieve your ends under that reason, any happiness gained is not necessarily due to the achieved ends, but instead due to the intentions one had for them.