Sorry to be a while answering these. It's been a busy couple of weeks.
Plato doesn't actually talk about a "Logos". That's a Stoic term. Plato has a World Soul (in the Timaeus); it was only later that the Middle Platonists combined this concept with the Stoic divine Logos to come up with an entity which orders and runs the world, but which is lower than the "High God". This is the basic view we find in figures such as Philo, Plutarch, and Alcinous.
The question whether the prologue to John draws on this kind of philosophical worldview, or whether it is more properly interpreted in the context of Jewish Wisdom literature (compare Proverbs 8:22 etc), is a very contentious one. I don't think there is a scholarly consensus at all. Of course it's made particularly tricky by the fact that some of the Jewish Wisdom literature itself was apparently influenced by Greek philosophy; I believe that the book of Ecclesiasticus (Sirach) is thought to show the influence of Stoic Logos ideas.
It's only when you get to Justin Martyr that the influence of the Greek Logos is very clear - although there is still controversy over exactly where Justin got it from, and in particular, whether he was familiar with Philo. The question is whether Justin was following John's lead in applying Logos philosophy to Christ, or whether he was innovative in assimiliating John's non-philosophical Logos and the Greek philosophical one.
I don't know exactly when the Jews became monotheists, because that's really not my field, but it was certainly long before the time of Jesus. I'm sure it was at least before the Exile, since the Pentateuch dates from around that time and it's certainly monotheist (although I suppose it doesn't follow that all the Jews were monotheist then). But monotheism was definitely one of the agreed absolutes among the various religious groups in Jesus' day.
I don't think those forms of paganism and magic were very influential on early Christianity. The early Christians thought all such things were wrong and avoided them. Now some later magical theory proved to have some influence. Iamblichus, for example, tried to use Neoplatonic principles to show how magic (theurgy) worked. Pseudo-Dionysius later incorporated some of these into his own work, and borrowed the very term theurgy itself - but for him it referred to the sacraments. However, I think this sort of thing was really a borrowing of details rather than the main outlines.
Neoplatonism was much more influential, as that last example illustrates; I think Plotinus was definitely the most important non-Christian influence upon Christianity in late antiquity. If you read Gregory of Nyssa, for example, you'll find much of what he says could be lifted straight from Plotinus (except that Gregory can write well). The idea of the supreme reality as the perfect Beauty, the source of all beauty in the lower realms, and the task of the soul to look upwards towards it and order itself according to the divine Beauty, and then bring order to the lower parts of the soul and the body - all very Neoplatonic and central to Cappadocian theology. Other theologians highly influenced by Neoplatonism include Marius Victorinus, but he wasn't very influential himself, because no-one could understand him (as even Jerome admitted!).
Probably the most well known aspect of Neoplatonism to become incorporated into Christianity was the analysis of evil as non-being, which both the Cappadocians and Augustine made central to their thought. Although it's worth pointing out that this wasn't necessarily an exclusively Neoplatonic idea. Origen had said the same thing, and he was a generation older than Plotinus (they supposedly had the same teacher, Ammonius Sacchas, who is sometimes credited with being the true founder of Neoplatonism - without any real foundation, since we know nothing about him or his teachings).
One shouldn't over-stress the influence of Neoplatonism on early Christianity, though, because there always remained major differences. For example, although Plotinus talked about three hypostases which bear a superficial resemblance to the three hypostases of the Christian Trinity, they are really completely different. For a Neoplatonist, reality spreads down in a fairly uniform way from the ultimate One (or whatever) down to matter (or at least, material bodies). But for a post-Nicene Christian, there was a fundamental division between the divine on the one hand and created things on the other. A Christian also could not hold matter to be the principle of chaos and evil, as some Neoplatonists tended to believe, since a Christian believed matter to be God's creation just as much as anything else, and therefore fundamentally good.
As for Philo, he was quite influential - perhaps more as an example of how to combine a semitic faith with Greek philosophy, rather than as a direct source of ideas. Quite a few Christian authors spoke approvingly of "Philo Judaeus" and by the Middle Ages he was practically an honorary, though minor, church father. His use of the "Logos" was clearly important, although as I said before, it's uncertain whether this was a direct influence on Justin and Clement or whether they were independently doing the same thing. His idea of interpreting the Bible allegorically, just as pagan rhetoricians did with the Greek classics, was hugely important. Indeed, even details of his allegories became standards in Christian exegesis. For example, Philo interpreted the life of Moses as an allegory of the mystic drawing closer to God. Origen did exactly the same thing, even incorporating details of Philo's explanations (for example, when Moses takes off his sandals to approach the burning bush, this symbolises the need to turn away from physical things in order to contemplate God). Gregory of Nyssa did the same thing in his own Life of Moses, and so the tradition continued.
It depends on what period you're talking about. If you're talking about (say) the second to the fifth centuries, I think the differences tend to be a bit over-exaggerated. For example, people often talk about two rival "schools" of theology, Alexandria and Antioch/Constantinople. Supposedly, the former tended to Origenism, engaged in allegorical exegesis of the Bible, and tended towards logos-sarx christologies. And the latter disapproved of Origen, engaged in typological exegesis of the Bible, and tended towards Nestorian christologies. Personally I think this a caricature. Origen met more opposition in Alexandria than he did anywhere else. Eutyches, the most extreme "Alexandrian" christologist, was trained at Antioch and lived near Constantinople. And the difference between allegorical and typological exegesis is really overblown. There is a subtle theoretical difference, but in practice no difference at all. For example, it's true that Theodore of Mopsuestia set out different principles of exegesis from Origen, and even attacked Origenist allegory; but then Origen himself didn't follow his own rules of exegesis. In practice, both these exegetes, like most from both "schools", distinguished between a "plain" or "literal" sense of the text and an "edifying" one; whether they thought it was edifying because it was an allegory or because it was a type didn't really make much difference, and I'm sure their readers didn't care.
There were linguistic differences, of course. Initially, Christianity was an almost exclusively Greek-speaking religion; even the Christians in Rome were speaking Greek well into the second century. Then it settled down into the three great linguistic groups - Latin in the western empire, Greek in the eastern empire, and Syriac in Persia and the border cities. This did lead to differences in practice and doctrine. For example, after the second century, the Syriac-speaking churches stopped using the four canonical Gospels and instead used the Diatesseron of Tatian, a Gospel harmony. This went on until the fifth century, when Rabbula of Edessa suppressed the Diatesseron and re-instated the canonical Gospels, bringing the Syriac-speaking church back into harmony with everyone else. Differences in language exacerbated differences in doctrine - for example, during the Arian crisis, most westerners didn't understand what the easterners were talking about with their language of ousia and hypostasis, and they tended to assume that all easterners were Arians (just as the easterners tended to assume that all westerners were Sabellians). The Syriac-speakers, for their part, sat out the Arian conflict because they were too busy being horrifically persecuted.
Not at all, questions like that are fine.
I've never read it, so I don't know.
Plato doesn't actually talk about a "Logos". That's a Stoic term. Plato has a World Soul (in the Timaeus); it was only later that the Middle Platonists combined this concept with the Stoic divine Logos to come up with an entity which orders and runs the world, but which is lower than the "High God". This is the basic view we find in figures such as Philo, Plutarch, and Alcinous.
The question whether the prologue to John draws on this kind of philosophical worldview, or whether it is more properly interpreted in the context of Jewish Wisdom literature (compare Proverbs 8:22 etc), is a very contentious one. I don't think there is a scholarly consensus at all. Of course it's made particularly tricky by the fact that some of the Jewish Wisdom literature itself was apparently influenced by Greek philosophy; I believe that the book of Ecclesiasticus (Sirach) is thought to show the influence of Stoic Logos ideas.
It's only when you get to Justin Martyr that the influence of the Greek Logos is very clear - although there is still controversy over exactly where Justin got it from, and in particular, whether he was familiar with Philo. The question is whether Justin was following John's lead in applying Logos philosophy to Christ, or whether he was innovative in assimiliating John's non-philosophical Logos and the Greek philosophical one.
I don't know exactly when the Jews became monotheists, because that's really not my field, but it was certainly long before the time of Jesus. I'm sure it was at least before the Exile, since the Pentateuch dates from around that time and it's certainly monotheist (although I suppose it doesn't follow that all the Jews were monotheist then). But monotheism was definitely one of the agreed absolutes among the various religious groups in Jesus' day.
I don't think those forms of paganism and magic were very influential on early Christianity. The early Christians thought all such things were wrong and avoided them. Now some later magical theory proved to have some influence. Iamblichus, for example, tried to use Neoplatonic principles to show how magic (theurgy) worked. Pseudo-Dionysius later incorporated some of these into his own work, and borrowed the very term theurgy itself - but for him it referred to the sacraments. However, I think this sort of thing was really a borrowing of details rather than the main outlines.
Neoplatonism was much more influential, as that last example illustrates; I think Plotinus was definitely the most important non-Christian influence upon Christianity in late antiquity. If you read Gregory of Nyssa, for example, you'll find much of what he says could be lifted straight from Plotinus (except that Gregory can write well). The idea of the supreme reality as the perfect Beauty, the source of all beauty in the lower realms, and the task of the soul to look upwards towards it and order itself according to the divine Beauty, and then bring order to the lower parts of the soul and the body - all very Neoplatonic and central to Cappadocian theology. Other theologians highly influenced by Neoplatonism include Marius Victorinus, but he wasn't very influential himself, because no-one could understand him (as even Jerome admitted!).
Probably the most well known aspect of Neoplatonism to become incorporated into Christianity was the analysis of evil as non-being, which both the Cappadocians and Augustine made central to their thought. Although it's worth pointing out that this wasn't necessarily an exclusively Neoplatonic idea. Origen had said the same thing, and he was a generation older than Plotinus (they supposedly had the same teacher, Ammonius Sacchas, who is sometimes credited with being the true founder of Neoplatonism - without any real foundation, since we know nothing about him or his teachings).
One shouldn't over-stress the influence of Neoplatonism on early Christianity, though, because there always remained major differences. For example, although Plotinus talked about three hypostases which bear a superficial resemblance to the three hypostases of the Christian Trinity, they are really completely different. For a Neoplatonist, reality spreads down in a fairly uniform way from the ultimate One (or whatever) down to matter (or at least, material bodies). But for a post-Nicene Christian, there was a fundamental division between the divine on the one hand and created things on the other. A Christian also could not hold matter to be the principle of chaos and evil, as some Neoplatonists tended to believe, since a Christian believed matter to be God's creation just as much as anything else, and therefore fundamentally good.
As for Philo, he was quite influential - perhaps more as an example of how to combine a semitic faith with Greek philosophy, rather than as a direct source of ideas. Quite a few Christian authors spoke approvingly of "Philo Judaeus" and by the Middle Ages he was practically an honorary, though minor, church father. His use of the "Logos" was clearly important, although as I said before, it's uncertain whether this was a direct influence on Justin and Clement or whether they were independently doing the same thing. His idea of interpreting the Bible allegorically, just as pagan rhetoricians did with the Greek classics, was hugely important. Indeed, even details of his allegories became standards in Christian exegesis. For example, Philo interpreted the life of Moses as an allegory of the mystic drawing closer to God. Origen did exactly the same thing, even incorporating details of Philo's explanations (for example, when Moses takes off his sandals to approach the burning bush, this symbolises the need to turn away from physical things in order to contemplate God). Gregory of Nyssa did the same thing in his own Life of Moses, and so the tradition continued.
It depends on what period you're talking about. If you're talking about (say) the second to the fifth centuries, I think the differences tend to be a bit over-exaggerated. For example, people often talk about two rival "schools" of theology, Alexandria and Antioch/Constantinople. Supposedly, the former tended to Origenism, engaged in allegorical exegesis of the Bible, and tended towards logos-sarx christologies. And the latter disapproved of Origen, engaged in typological exegesis of the Bible, and tended towards Nestorian christologies. Personally I think this a caricature. Origen met more opposition in Alexandria than he did anywhere else. Eutyches, the most extreme "Alexandrian" christologist, was trained at Antioch and lived near Constantinople. And the difference between allegorical and typological exegesis is really overblown. There is a subtle theoretical difference, but in practice no difference at all. For example, it's true that Theodore of Mopsuestia set out different principles of exegesis from Origen, and even attacked Origenist allegory; but then Origen himself didn't follow his own rules of exegesis. In practice, both these exegetes, like most from both "schools", distinguished between a "plain" or "literal" sense of the text and an "edifying" one; whether they thought it was edifying because it was an allegory or because it was a type didn't really make much difference, and I'm sure their readers didn't care.
There were linguistic differences, of course. Initially, Christianity was an almost exclusively Greek-speaking religion; even the Christians in Rome were speaking Greek well into the second century. Then it settled down into the three great linguistic groups - Latin in the western empire, Greek in the eastern empire, and Syriac in Persia and the border cities. This did lead to differences in practice and doctrine. For example, after the second century, the Syriac-speaking churches stopped using the four canonical Gospels and instead used the Diatesseron of Tatian, a Gospel harmony. This went on until the fifth century, when Rabbula of Edessa suppressed the Diatesseron and re-instated the canonical Gospels, bringing the Syriac-speaking church back into harmony with everyone else. Differences in language exacerbated differences in doctrine - for example, during the Arian crisis, most westerners didn't understand what the easterners were talking about with their language of ousia and hypostasis, and they tended to assume that all easterners were Arians (just as the easterners tended to assume that all westerners were Sabellians). The Syriac-speakers, for their part, sat out the Arian conflict because they were too busy being horrifically persecuted.
Not at all, questions like that are fine.
I've never read it, so I don't know.
