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.

In fact one of the things about Plotinus is that he maybe not singlehandedly, but I think more than anyone else, killed off the variety and dissension among the philosophical schools of antiquity.

People often talk about Plotinus' system. The reason they do this is that Plotinus postulated a kind of series or chain of principles, so at the top there's what he called the One. Below the One is what he called Intellect. Below Intellect is Soul, and the effect of the soul is the physical world that we actually live in.

The idea is that to grasp an idea like equality or justice, you can't look at the equal and just or unjust things in the world around you, you have to somehow ascend to or maybe remember some kind of idea of equality and justice and this would be a Platonic form, and it would be different from the things that partake in the form.

Basically the problem is that if the intellect is looking at or beholding the forms, what it will get is some kind of representation or image of the forms, but it won't actually have the forms, it won't touch them as it were, or it won't incorporate them.

For Plotinus, what really exists are the Platonic forms, so the true nature or form of things like justice, beauty, maybe numbers, things like that, and these he associates with the intellect because they're the objects of intellect, they are things that intellect can think about.

This condition of uncertainty and unrest in the Roman Empire might explain why at Plotinus' philosophy encourages us to sort of flee from the physical world and towards the world of ideas.