The neutral mind is the 3rd mind, and the mind that we strive for.
The negative mind is the first mind. It is the one that assesses situations based on fear. It develops because it helps us survive.
The positive mind is the second mind. It is the one that gives us joy, the rose tinted glasses. It develops to help us see the bright side. Without hope, we stop striving.
The neutral mind is where these two minds converge so that we have an accurate perception of pros and cons for making every choice. With the neutrality, we are distanced, objective, and realistic.
However, I argue that our idea of realism as a society is skewed towards the negative. Mostly skeptics and pessimists will tell you you're not realistic when you're optimistic. Realism in our current view keeps our expectations down so that we don't get disappointed. Our current anchor of realism is not where it should fall. Where it should fall is in neutrality where we have perspective.