6 ideas
You cannot decide whether something has a property, such as being teachable, until you know what the thing is. Socrates refuses to answer Meno's question about acquiring virtue until they have a definition, because every judgment about a thing's attributes depends on its essence.
When Meno defines virtue by listing a man's virtue, a woman's, a child's, and a slave's, Socrates rejects the list as a swarm of bees. A definition must name the single form that all the cases share, which is what makes each of them count as an instance, instead of enumerating the instances.
If you already know what you are looking for, you don't need to search for it. If you don't know it, you cannot search, because you wouldn't recognize it if you found it. The dilemma threatens every attempt to learn something genuinely new.
Socrates questions an untutored slave boy about how to double a square's area and never tells him the answer. The boy first answers wrongly with confidence, then reaches helpful confusion, then finds the diagonal as the solution. Socrates presents this as evidence that the knowledge was drawn out of the boy, not put into him.
The soul is immortal and has already seen all things, so what we call learning is recovering knowledge it already holds. Guided questioning triggers the recovery, which dissolves Meno's paradox: we search for what we have forgotten and recognize it when we find it.
A true opinion guides action as well as knowledge does, but like the statues of Daedalus it runs away unless tied down. Working out the reason why it is true fastens it and turns it into stable knowledge. Because good statesmen have left no successful teachers of virtue, Socrates concludes their virtue was untethered true opinion that came by divine dispensation.