cast Archaeomancer with no instant or sorcery card in my graveyard?

[kinda]

can I Cast Archaeomancer if I dont have neither instant nor sorcery card in my graveyard yet?

[Kenji]

Yes, that's fine. Although it's true that you need a legal target to cast a spell that targets, here's the thing:

Creature spells never target.

Archaeomancer, the spell, doesn't target a single thing. It has a triggered ability that targets a card in the graveyard, but that doesn't even go on the stack until Archaeomancer, the creature, has entered the battlefield.

[kinda]

it says target

[Kenji]

Yes, it does. But here's the thing, say it with me again:

Creature spells never target.

I can clarify that further, to make it easier to understand:

At the time you cast a creature spell, there is never a situation where you have to announce a target for that creature spell.

I acknowledged that it says target. Look, I'll go ahead and quote it for you:

When Archaeomancer enters the battlefield, return target instant or sorcery card from your graveyard to your hand.

Yes, this triggered ability targets. And? As I mentioned above, this triggered ability doesn't even go on the stack until after you've successfully resolved Archaeomancer. Of course, if there are no instant or sorcery cards in the graveyard, the ability will simply do nothing.

Again, the trigger even is "When Archaeomancer enters the battlefield." Why would you announce a target for this ability when you cast Archaeomancer? The answer is simple -- you don't, because it's not even guaranteed that Archaeomancer will even enter the battlefield (it can be countered, for example), so of course its triggered ability hasn't triggered yet.

Does that make sense to you now? If not, I can attempt to explain it further, but it's already pretty simple.