saying that things that are morally adiaphora (indifferent) could nevertheless have value. Things have a relative value in proportion to how they aid the natural instinct for self-preservation. That which is to be preferred is a "fitting action" (kathêkon/καθῆκον), a designation Zeno first introduced. Self-preservation, and the things that contribute towards it, has only a conditional value; it does not aid happiness, which depends only on moral actions. Just as virtue can only exist within the dominion of reason, so vice can only exist with the rejection of reason. Virtue is absolutely opposed to vice, the two cannot exist in the same thing together, and cannot be increased or decreased; no one moral action is more virtuous than another. All actions are either good or bad, since impulses and desires rest upon free consent, and hence even passive mental states or emotions that are not guided by reason are immoral, and produce immoral actions. Zeno distinguished four negative emotions: desire, fear, pleasure and sorrow (epithumia, phobos, hêdonê, lupê / ἐπιθυμία, φόβος, ἡδονή, λύπη), and he was probably responsible for distinguishing the three corresponding positive emotions: will, caution, and joy (boulêsis, eulabeia, chara / βούλησις, εὐλάβεια, χαρά), with no corresponding rational equivalent for pain. All errors must be rooted out, not merely set aside, and replaced with right reason. Works None of Zeno's original writings have survived except as fragmentary quotations preserved by later writers. The most famous of his works was Zeno's Republic, written in conscious imitation of, or opposition to, Plato's Republic. Although it has not survived, more is known about it than any of his other works. It outlined Zeno's vision of the ideal Stoic society. A manuscript that was attributed to Zeno, matching a known title of one of Zeno's works, Περὶ φύσεως (On Nature), was discovered in 1949 in an Old Armenian translation. In 1956 it was translated into Russian and published with an extensive commentary. Subsequent philological investigation concluded that the author could not have been Zeno and was instead an anonymous Christian philosopher of the late sixth century or a little later, writing in the tradition of ancient philosophy, but doing so as a Christian. He is now known as Pseudo-Zeno. His work shows an integration of Christian and philosophical concepts, but in a very restrained way. The titles of many of Zeno's writings are, however, known and are as follows: Ethical writings: Πολιτεία