[quote="manualman, post:13, topic:302065"]
Be careful with such reasoning. It's the "similarity implies descent" argument and it's fallacious. As in the evolutionary debate, finding an earlier similarity doesn't prove that the later specimen is merely a naturally occurring mutation. On the contrary, it MIGHT simply be a reflection of the fact that each had a common designer. This is the case both for evolution and religious practice. Sometimes there ARE similarities. Many cultures have ancient flood disaster stories. Some scholars argue that this simply proves the the bible is a myth that borrowed from earlier tales. It's a weak argument since both stories could ALSO simply be indepedent accounts handed down from the time of an ACTUAL flood disaster. You can't tell.
Similarly, protestant christians sometimes attach catholics in the same way, pointing out ancient cultures that venerated a woman who gave birth to a Son of God, etc. Same fallacious reasoning.
Islam isn't erroneous because it has some similarities to earlier pagan cultures. It is erroneous because it denies the divinity of Christ, the Trinity and the death and resurrection of our Savior to save us from our sins (among other important details!).
While from your wording I think we likely hold somewhat different positions on evolution, your analogy is a good one. In biology we distinguish between homologous traits, which are derived from common descent, and analogous traits, which are similar traits that developed independently. Thus for example the wings of robins and ravens are homologous, while those of bats and bees are analogous.
Many cultures have, for instance, celebrated winter holidays around the time of the Winter Solstice, and used evergreen vegetation to create a more festive atmosphere at a rather bleak time of year. That doesn't mean that these similarities are always derived from a common historical origin, even when they arise in cultures in close proximity to each other.
Also, even if there is a genetic relationship between two customs, it may be the reverse of what some people are likely to assume. Samhain, for example, is not attested to until well after All Saints Day was being observed on November 1. If one was derived from the other it could easily have been a secluar/paganistic Samhain borrowed from the Christian holiday at least in terms of its exact date, not the other way around.
On the other hand, I thought the pagan origin of the Kaaba and its black stone was very well attested.