vii.; Adv. Praxeam, vii). However Tertullian used 'corporeal' only in the Stoic sense, to mean something with actual material existence, rather than the later idea of flesh. Tertullian is often considered an early proponent of the Nicene doctrine, approaching the subject from the standpoint of the Logos doctrine, though he did not state the later doctrine of the immanent Trinity. In his treatise against Praxeas, who taught patripassianism in Rome, he used the words "trinity", "economy" (used in reference to the three persons), "persons", and "substance," maintaining the distinction of the Son from the Father as the unoriginate God, and the Spirit from both the Father and the Son (Adv. Praxeam, xxv). "These three are one substance, not one person; and it is said, 'I and my Father are one' in respect not of the singularity of number but the unity of the substance." The very names "Father" and "Son" indicate the distinction of personality. The Father is one, the Son is another, and the Spirit is another ("dico alium esse patrem et alium filium et alium spiritum" Adv. Praxeam, ix), and yet in defending the unity of God, he says the Son is not other ("alius a patre filius non est", Adv. Prax. 18) as a result of receiving a portion of the Father's substance. At times, speaking of the Father and the Son, Tertullian refers to "two gods". He says that all things of the Father belong also to the Son, including his names, such as Almighty God, Most High, Lord of Hosts, or King of Israel. Though Tertullian considered the Father to be God (Yahweh), he responded to criticism of the Modalist Praxeas that this meant that Tertullian's Christianity was not monotheistic by noting that even though there was one God (Yahweh, who became the Father when the Son became his agent of creation), the Son could also be referred to as God, when referred to apart from the Father, because the Son, though subordinate to God, is entitled to be called God "from the unity of the Father" in regards to being formed from a portion of His substance. The Catholic Encyclopedia comments that for Tertullian, "There was a time when there was no Son and no sin, when God was neither Father nor Judge." Similarly J.N.D. Kelly stated: "Tertullian followed the Apologists in dating His 'perfect generation' from His extrapolation for the work of creation;