Mad people don't know they are mad. I know I am, therefore I am not.

"Begin with a function of arbitrary complexity. Feed it values, "sense data". Then, take your result, square it, and feed it back into your original function, adding a new set of sense data. Continue to feed your results back into the original function ad infinitum. What do you have? The fundamental principle of human consciousness."

In essence, we change the world by reacting to it. We learn about the world, we act on that knowledge, and we change the world, thus changing our knowledge of it and our following actions. But what if there is no consciousness, only a vessel for it? Where does consciousness even begin, what is it?

In medicine, a person is called braindead if there is no reaction from the brainstem. That is to say spinal reflexes may work fine but regulatory controls (heat, CO2 levels) are nonresponsive, as is the person in general. Yet it has been shown that people in vegetative state sometimes can react to outside stimuli, just not with a visible reaction - the response can only be seen on an MRI. Sometimes people recover from vegetative states after being in it for years. Even modern technology has difficulty laying down the line from where there is no entity that could be called consciousness, there is no soul. Then again, medicine has never been an exact science.

"Each morning, we wake up and experience a rich explosion of consciousness — the bright morning sunlight, the smell of roast coffee and, for some of us, the warmth of the person lying next to us in bed. As the slumber recedes into the night, we awake to become who we are. The morning haze of dreams and oblivion disperses and lifts as recognition and recall bubble up the content of our memories into our consciousness. For the briefest of moments we are not sure who we are and then suddenly ‘I,’ the one that is awake, awakens. We gather our thoughts so that the ‘I’ who is conscious becomes the ‘me’ — the person with a past. The memories of the previous day return. The plans for the immediate future reformulate. The realization that we have things to get on with remind us that it is a workday. We become a person whom we recognize." - Bruce Hood

In this case, to be conscious is to be self-conscious. It is to know that you are a person who is currently 'active'. In this case, consciousness is lost if you fall asleep. Unless you are experiencing lucid dreams, in which case you know you are who you are and that you are in control of your dreams, but nobody else does. Thus, anyone trying to ascertain whether a sleeping person is conscious or not is facing a problem not unlike Schrödinger's cat. And in this case, as in Schrödinger's, the object of study can get really tired of your experiments and just run off.
Then again, there is no shortage of people reporting out of body experiences. If it were just one or two people among billions, it might be contributed to just normal insanity, but I'd venture to say most of us have had, even remember, at least one episode from our lives where something really bizarre and incomprehensible occurred where we weren't quite... in ourselves. A common neural misfiring no doubt, but a person experiencing such an event, and understanding consciously that he or she is not he nor she at that moment would presumably effectively mean they are unconscious. If that were true, you could be consciously aware that you are unconscious. Whoops.

So how to actually know if a person is conscious? This is made remarkably difficult as the person whose status we are attempting to assess might not just not know whether they are conscious or not, they could consciously be both. I guess what they say is true, "'Normal' is just a cycle in the washing machine.". Perhaps we are all mad. Just going round like a spiral, like a wheel within wheel, never ending or beginning on an ever-spinning reel. Like the circles that you find in the windmills of your mind.

'One may tolerate a world of demons for the sake of an angel.'

Now that we've assessed what a good leader is like[1], time to go wider. A good person. What is a good person like, how would he/she act?

There are plenty of people who don't appear to be very noble or 'good', but are told to have hearts of gold. People who don't act as good as they are, for one reason or other. Sometimes due to peer pressure, sometimes due to necessity, sometimes because they really are pricks. But the most objective way of determining whether a person is 'good' or not is by observing the actions. After all, it is the actions that we can observe, so far we have not been able to peek into the soul of a person.
While it is difficult to define 'good' actions, some generalizations can be made. For instance, a 'good' person would not willingly betray someone's trust if there is an option not to and not cause a more negative effect by the act of non-betrayal. In essence, he/she will choose the action presenting in the least harm coming to the fewest people.

"The happy life is thought to be one of excellence; now an excellent life requires exertion, and does not consist in amusement. If Eudaimonia, or happiness, is activity in accordance with excellence, it is reasonable that it should be in accordance with the highest excellence; and this will be that of the best thing in us." - Aristotle

Now that is a difficult guideline to follow. Situations that befall us are rarely so black and white. Just look at the Doctor: there is a man with a choice, either let a single planet of his own kind perish or spell doom for the whole Universe. On a mathematical scale it is no choice at all, one life for billions. On a personal scale, it is trading all he knows, everyone like him, his home, his life, for people he knows nothing about. We were told that was the choice he had to make, yet it is not the choice that was described afterwards. Now we know the choice was not whether to save a few and sacrifice the many or to save many and sacrifice the few. It was whether or not to use a planet full of life as bait to lure yet another civilization to near extinction. It is not a choice that is easily made. If he chose not to, his planet would still have died. Then again, would a 'good' man kill millions of beings for doing what they believe in just because he fancies it?

But of course fiction is riddled with ethical dilemmas, it is what makes it so addictive and educative. But that is not to say ethical problems are smaller in real life. Take doctors for example. They have the responsibility of manipu... er... convincing people that what doctors deem to be best thing to do is actually factually the best possible thing to do. Even if the people do not accept that as the truth. Sure, belief in the medical system is a huge part of getting better, but often patients (and/or their relatives) are put in front of a choice where there is only a single accepted answer. And not just in the case of pulling the plug on braindead patients or harv.... er... donating their organs. Though you might think 'surely when a person makes a decision that's it, surely a decision is a decision', but that is only true if it is the decision the doctors want, otherwise it is only a temporary setback. While it may not appear ethical at first sight (that's why they don't call it 'manipulating' when it so clearly is), it serves a greater goal. That goal being gaining more resources to help those who would actually benefit from their help, instead of tying them up for people who have no practical use for the resources or ever will. Helping more people surely must be ethical, right?

"You cannot have a greater ideal with the smaller ones being compromised."

If a good person aims to be good, to be excellent, then his actions cannot in any step conflict with his beliefs. Then again, often if he refuses those actions, the consequences are even worse in regards to his beliefs. As Sheppard Book used to say: "If you can't do something smart, do something right.". Beyond that it's a crapshoot.