L.A. lyrical artisan Echo celebrates the wisdom of historical figures on “Rap Philosophiæ: Book I.” On this potent platter, each joint focuses on a different philosophers’ lessons. From “Epictetus,” which embodies the Stoic philosopher thinking to put effort into what we can control and not what we can’t, to author James Baldwin’s powerful mindset on perseverance and strength, and much more. Knowledge is abundant here and flows through this masterwork, including a glimpse into this inventive emcee’s philosophy