It's worse than that. Water having a memory, spiritual or otherwise, of things it used to carry, would be downright simple compared to what homeopathy posits. Considering everything all the water on Earth has been through, you'd expect it to be full of memories of all sorts of stuff; not just the last homeopathic remedy you put in it. What homeopathy requires is that water has a memory of things that it has held, which has to be primed by a specific procedure, namely thumping the container of water against a leather pad stuffed with horse hair while the solute is still in it so the water will remember it. The process is called "succussion" and the inventor of homeopathy thought that it made his remedies stronger. Later advocates though, realized the implications of the "water has a memory" hypothesis, and so rationalized it as necessary.