Well imagine how you’d get home from school without a memory? Even the simplest animals have memories, for exactly that kind of task. There’s an interesting difference between semantic memories, which is things like just knowing things, like Paris is the capital of France, and episodic memories, which is remembering particular things that actually happened. You probably remember Paris is the capital of France, but not the specific episode in your life when you learnt that fact. So that’s a semantic memory without an episodic memory. Knowing how to get home is a semantic memory, although if you remember the first time you went home, that’s episodic. Semantic memory is a bit simpler, it helps you get basic stuff done. A lot of psychologists think only humans have episodic memory.