The idea that many of the myths around Jesus had been seen around Horus first. Born of a virgin. Killed and resurrected. Calming the storm. Sermon on the Mount. Visited by magi as a baby. i.e., a whole bunch of the Jesus story was borrowed from Horus mythology.
I don't really know much about Egyptian religion, so I'm not competent to say whether these things were really believed of Horus. Without access to reliable sources my initial reaction is to be sceptical. One sees claims of this kind all over the Internet, sometimes about Horus, sometimes about Mithras, and so on. They rarely give sources for the claims, and when they do, they are usually nineteenth- or early twentieth-century secondary literature. Now I know for a fact that the claims you often see about Mithras (he was born in a stable, he rose from the dead, etc) are just not true. Where there are similarities between him and Jesus they are mostly minor or to be expected from anyone worshipped as a god. So I would tend to expect the same thing to turn out to be the case with other supposed "originals" of Jesus such as Horus, but right now at least I can't say anything more authoritative on that particular case.
However, I can at least point out a general difference between the claims made about Jesus and those made about other ancient gods. As I said before, the stories about Horus, Mithras, and so on are firmly in the category of myth. They are not set at particular times or places. The characters are not human beings, but legendary heroes or gods. The events are of cosmic significance and intended to express fundamental truths about human nature, cosmic nature, or particular facts of nature such as why deserts are arid, why the Nile floods, and so on. It is not clear if the events are supposed to have happened in an impossibly distant past or if they are supposed to occur timelessly in a sort of parallel mythic timeline. It is not even clear if they happen once for all or if they recur constantly, perhaps following an annual cycle.
None of these things is true of the stories told about Jesus. Jesus was a particular historical figure who lived at a particular historical time and place. The Gospels do not read anything like the mythic literature (to the extent that that survives) associated with other ancient religions. There certainly is Christian literature of that kind, most notably gnostic literature describing events in the Pleroma and suchlike, but the Gospels are really nothing like it.
To put it another way, you can, perhaps, make it seem like there are striking parallels between the things believed of Jesus and the things believed of other gods if you take those beliefs out of context, turn them into brief summaries, and set them side-by-side in neat columns, as amateur religious historians on the Internet so love to do. But you don't really demonstrate much of interest by doing that. If you look at the actual texts and bodies of narrative in which these beliefs are embedded, the supposed similarities are much harder to spot. And of course they will be surrounded by striking dissimilarities too.
Many 'Christian' notions are simply incorporated into Christian theology from older religions. (One might even say that there's not an original thought in Christianity that's not taken from earlier religions; with this, there's a similarity to the Roman pantheon, which simply incorporated earlier or 'barbaric' religious ideas into a Roman overlay.)
I don't think that this is true. I mentioned above that many of these theories that Christian beliefs about Jesus were taken from pagan beliefs about other gods seem to appeal to nineteenth- or early twentieth-century scholarly literature, not recent scholarship. That is because notions such as this were very much in vogue at that time. A group of German scholars, in particular, known as the "history of religions" school, developed these ideas. Their methodology was based, in part, upon the supposition that ideas are transmitted from one religion to another, and that innovation is rare; so the content of one religion can generally be explained more or less fully by reference to earlier or contemporary religions as sources for it. They applied this to Christianity and concluded that everything in Christianity came from pagan religion.
Most scholars over the past fifty years or so have rejected these ideas. This was partly because they have rejected the underlying assumptions - that religions develop only by nicking stuff from other religions - and also because there is much greater recognition both of the differences between Christianity and pagan religions and of the originality of Christian theologians in developing ideas fairly autonomously. The points I made above about supposed "originals" of Jesus in other religions are generally accepted today, I think. Also, where Christianity is seen to have taken ideas from earlier religions, scholars have been much more likely to see Judaism as the source rather than paganism. In fact this tendency reached a peak perhaps twenty or thirty years ago, with some scholars seeing pretty much everything in Christianity as coming from Judaism; the pendulum has perhaps swung somewhat the other way since then, with a more balanced view.
Personally, however, I do think that the parallels between Christianity and Judaism, especially certain ideas that were knocking around in Judaism in the first or second centuries AD, are far greater than the supposed parallels between Christianity and pagan religions. It seems unnecessarily complicated to try to draw great comparisons between the Christian view of Jesus and the Egyptian view of Horus, when even if such comparisons are reasonable there is no reason to suppose that Christians were notably influenced by traditional Egyptian religion, when instead you could focus on the very obvious comparisons between the Christian view of Jesus and the Jewish view of Enoch and Metatron as developed in the later Enochian literature, when we know that Christianity did take rather a lot of stuff from Judaism.
Also, many of these myths weren't a part of Jesus' ideas during his lifetime, but became part of the Messiah myths intended to show that he was the Son of God - later even God himself, as in the Holy Trinity doctrine.
This doesn't make much sense to me. "Messiah" has got nothing to do with "Son of God", and the doctrines supposedly drawn from pagan religions have got nothing to do with either of them. The doctrine of the Trinity is quite distinct again. In fact the doctrine of the Trinity is a good example of something unique to Christianity, which developed within Christianity as a result of various pressures and influences, but mostly internal to the religion. Certainly it was originally inspired - to some extent - by ideas drawn from pagan philosophy (not pagan popular religion so much), but it developed according to a Christian logic of its own. Again, in the nineteenth century it was fashionable to try to draw parallels between the Christian Trinity and things such as Plotinus' three hypostases, but again, the similarities were largely shallow and the differences very deep.
An even better example would be the doctrine of the incarnation. I don't think any other ancient religion had anything quite like the notion of a fully divine person becoming fully human and retaining both natures at once. Indeed, the notions of "person" and "nature", in which the doctrine was couched, were developed largely by Christian theologians for the purpose of expressing the doctrine.
What's the difference between the 'original' Manichaeans and the Bogomils? Were the latter just a revival of the concept in Eastern Europe or were they a revision of sorts, and if so what particular doctrines (if they can be called that) were changed?
I think this is a very poorly understood area, so there isn't a definitive answer to this question. Basically, no-one really knows what happened to the Manichaeans, exactly, or where the Bogomils got their ideas from, so your question is almost impossible to answer. It may be that the Bogomils were a revival of Manichaeanism, or they may have been quite independent. It is also possible that they were influenced by the Paulicians. The problem is that we know even less about the Paulicians than we do about both the Bogomils and the Manicheans - we don't even know if the Paulicians were dualists or not, whereas we are at least pretty certain that the others were. If the Paulicians were dualists, then there may have been a fairly straight line of influence from Manichaeans to Paulicians to Bogomils. If they weren't, the influence may have gone from the Manicaeans direct to the Bogomils - or it may not.
Extending the problem in both directions in time, it is also uncertain where the early gnostics fit into this, and also where the later Cathars fit in. It is unknown whether the Manichaeans took ideas from the gnostics or arrived at similar ideas independently, and it's uncertain whether Bogomils fleeing Byzantine persecutions helped to inspire the Cathars in western Europe.
Part of the problem is that dualism of the kind that characterised most of these movements seems to be the sort of idea that tends to crop up quite often anyway. To explain dualist ideas in one group you don't have to posit influence from another dualist group, because most people seem to be quite capable of developing such ideas without outside help. So it is very hard to say.
it is not so much a philosophical question, but i guess it has philosophical meaning of a kind. In 1935, physicist Schrodinger proposed a thought experiment called popularly
Schrodinger's Cat.
In it he proposes, due to lack of observatory evidence, that the cat both is alive and dead. As a philosopher, would you subscribe to what is proposed here? What philosophical problems would this pose? (N.B. this experiment has never been carried out, but could be within our current technology.)
EDIT: i suppose this question is not really related to theology, but i would be interested in a philosopher's answers.
This is another thing I don't know much about! You really need to ask a philosopher of science, which I am not. However, as I understand it, Schrodinger didn't propose that the cat in the experiment would really be both alive and dead at the same time. The point was that the Copenhagen school of quantum physics thought that subatomic particles could be in different, contradictory states at the same time, until the contradiction is resolved by someone observing them, at which point they "flip" into just one of the states. Schrodinger's thought experiment was supposed to show that this view leads to absurd consequences, because you could set things up so that the state of the subatomic particle determines whether the cat is alive or dead, unobserved in the box. If the particle can really be in two states at once then the cat would be really dead and really alive at once, until someone opens the box and causes the particle to "flip" to just one state, and the cat with it. But this is obviously ridiculous, so there must be something wrong with the Copenhagen claim.
Clearly you couldn't prove things either way by actually carrying out the experiment, because the whole point is that the particle and the cat are unobserved. As soon as you look to see whether the cat is dead or alive, the Copenhagen theory would say that you determine which it is. The point is that it is surely obvious that the cat must be either actually dead or actually alive even when it is unobserved, no matter what subatomic particles you've got it hooked up to.
It seems to me that it is pretty easy to derive absurd consequences of this kind from the original supposition that something can be in two contradictory states at the same time until an observer resolves the contradiction simply by making an observation. For example, how do you define "observer" and what counts as making an observation?
Of course there have been plenty of philosophers who have proposed that the physical world is mind-dependent. I suppose that George Berkeley is the most famous, but similar views can be found among ancient Neoplatonists and also among Hegelians. But these forms of idealism all propose that physical objects are actually constituted from mental objects, such as ideas. They don't propose that physical objects are independent of the mind and yet also dependent on the mind to determine what states they are in, as the Copenhagen physicists proposed. That seems to me to be a strange half-way house between physicalism and idealism, open to the objections made against both yet without anything of its own to recommend it. But then I don't know much about physics so I don't know what led the physicists to propose such an idea in the first place.
