This is in a way the most important thing about soul is that it's a kind of principle which mediates between the universal intellect and the material world.

Plato in his dialogue The Phaedo says that whereas sticks and stones are both equal and unequal, (so maybe what that means is that each stick is going to be equal to some other sticks and unequal to some other sticks, so equal to the stick on the left maybe but shorter than the stick on its right) the form of equal is going to be just equal, and it won't partake of inequality at all. And it will be the cause of equality in things that are equal, for example, equal sticks and stones.

This is in a way the most important thing about soul is that it's a kind of principle which mediates between the universal intellect and the material world.

Plotinus is a neo-Platonist, so he would encourage us to go back to Plato.

Plotinus thought that the entire world has a single soul. He also thought that each animal and plant and of course human, has an individual soul.

Just the way you might look at a painting and see the painting, and the painting is outside you, so this immaterial intellect would see the forms and behold them, as if they were standing before it. And Plotinus said that that can't be right because it falls prey to sceptical objections.

Sometimes clichés are true.