History Memes

Yes to the former, kinda no to the latter. In Islamic jurisprudence just vaguely pointing towards the Kaaba is fine if you can't see it, based on among other things a hadith saying "anything between east and west is the qibla" in Medina where the qibla (direction of prayer) was southward. The prayer times are a bit more strict, but they're also ranges rather than precise timings so for example afternoon (Zuhr) prayer can/must be done anywhere between midday to mid-afternoon, while night (Isha) prayer can/must be prayed between nightfall and dawn. Prayer times also rely on obvious visual cues, so while you absolutely have to do the prayer within its time range, you'll see it before it ends. That said, you're ultimately correct in that they went a lot further than they had to in terms of Islamic doctrine, because Islam specifically addresses the possibility of not knowing precise prayer times and directions in ways other than "revolutionize mathematics."