Wait why would he write the book if he thinks it's wrong? As an illustrative proof that happy lives are impossible, by showing how absurd it would be to obtain one?
No, in the book it's quite clear that Schopenhauer thinks lives can be better or worse. (That's probably clear in his 'serious' philosophical works but I haven't read them). The advice in the book is genuinely aimed at making your life better. But Schopenhauer doesn't think it can make your life preferable to non-existence, because he thinks no possible life can meet that bar.
Wait why would he write the book if he thinks it's wrong? As an illustrative proof that happy lives are impossible, by showing how absurd it would be to obtain one?
No, in the book it's quite clear that Schopenhauer thinks lives can be better or worse. (That's probably clear in his 'serious' philosophical works but I haven't read them). The advice in the book is genuinely aimed at making your life better. But Schopenhauer doesn't think it can make your life preferable to non-existence, because he thinks no possible life can meet that bar.