"My philosophy, in essence, is the concept of man as a heroic being, with his own happiness as the moral purpose of his life, with productive achievement as his noblest activity, and reason as his only absolute."
As she herself confesses, this is a concept, her concept. I, for one, do not agree with this premise, and so everything flowing from it fails. Separate to this, she rambles and shambles on about moral purpose and productive achievement, let alone employing the term noble—I mean, really?
Let me paraphrase, These are things I like and think are important because I like them and think they are important. Sorry, but #FAIL.
One should not seek happiness that would in turn in infringe on other people's life or rights.
First, we need to ask why happiness is a goal followed very quickly by is happiness achievable—or perhaps more relevantly, is persistent happiness achievable. Current psychology says no, so this may be a fool's errand, tilting at windmills.
Without having an answer to this first line of questioning, the second part is not particularly meaningful.