What makes "common sense" ideas in ethics common sense? Consider the following examples:
- Example: Owner of a Pizza place, advertising his store with the following message: "Big chain of Pizzerias cannot produce the same quality of food as our small cozy store. come taste the difference".
Then, after a few years he becomes so successful that he opens up a chain of Pizzerias. If he were to advertise it as "Best Pizza ever, we treat every pizza as if it came from our personal home oven" he would be regarded as a phony by people, because he previously claimed it is impossible to produce high quality food in mass production.
Why would he be regarded as a phony? Because people realize in a common sense way, that if a principle is true a certain point in time, it should also be true for a later point in time. [An abstraction is true regardless of time]
- An example showing another aspect: A principle in ethics cannot be true for one man but not for another - it is true as an abstraction for every man. Every kid knows that if it is wrong for others to cheat in a game, it is wrong to cheat in a game, period. For others and for himself. Or if one kid accuses another kid for doing X (like talking during an important class), then it would be hypocritical for the blamer to do X and at the same time preach to someone else that doing X is wrong. A typical response a kid would give to such accusation under the circumstances is: "But you do it too!"
The two examples show that it is common sense that an evaluation of an action (as good or bad, just or unjust) cannot be isolated to a single instance - it must be a principle.
What makes it "common sense"?
To understand it, let's look at how human cognition works in regards to inanimate objects. If one object falls down when you release it from a height, and this happens with every object, then one concludes that objects fall down when released from a height. People would consider a lunatic a person who would go "this objects fall" "and this object falls" "and this object falls" "But what happens with this object? I don't know". In other words, our cognition functions seeking abstractions, generalizations, principles. This is how even the least intelligent (yet still rational) man thinks. Even if all he knows is how to grow oranges, he would still know that all orange trees needs water to grow, that this is the nature of an orange tree as a principle.
Deciding on shoulds, on right and wrongs in human behavior, is different than learning that objects fall and more complicated, but nonetheless, it remains the same that if a principle applies to one man, it applies to all men. If it is bad to murder, then it is bad to murder for everyone at every time. What makes this common sense, something that every kid understands, is the fact that our consciousness functions as an abstracting mechanism - this is the way we comprehend reality.
Therefore a thieve cannot feel guiltless and still hold that if someone steals his property he's bad. In the back of his mind he knows and feels that if he condemns someone for doing X, then he is bad as well for doing it. A thief therefore has to develop a different view of ethics that would make stealing alright. For example "it's a dog eat dog world. One must steal and kill to survive, it's just a question of who does it better". Such a view makes a justification as a principle for stealing. [as a side note, notice the destructive role this conclusion plays in his life. He will regard thieves as virtuous and seek their company, even though they are the most untrustworthy people out there, he will not have the moral ammunition to blame someone for stealing from him. He basically strips himself off a central principle for survival]
He may try to say that other people are bad if they steal from him, yet he is not bad for stealing from others - but then he would go against the very essence of his thinking, of how his mind grasps everything in the world. If X is wrong for men but not for him, even though he's a man, then generalizations as such cannot be trusted. If it is good for others to be happy, why would this mean that it is good for him as well? If a certain medicine is good to cure something for all men, who is to say that it is good for him as well? If it is wrong to grow orange trees without water, who is to say that this applies to any particular orange tree? He says in essence that generalizations about human nature and human behavior are illegitimate. But he cannot escape the fact that his consciousness acts seeking unity of his knowledge. If generaliazing about stealing is wrong, then generalizing as such should be doubted in other cases as well.
He will no longer be able to say with conviction "well of course it's good for people to be happy, that is human nature". And since he rejects his ability to form principles in ethics, he is left helpless to survive. He can no longer hope to find a reliable guide for action. How could he? What's good for humanity, what man should do to live a good life can no longer logically apply to him as well.
I think most people struggle to explain why things like murder, theft, dishonesty, etc' are bad on principle. The difficulty here is to comprehend that principles are equally valid to human actions as they are for the behavior of any other object or phenomenon.
Conclusion from all the above: Moral people are those who stay loyal to the understanding that a principle of human action is a principle. In other words, practice what you preach.
They may not know why this is right, they may only experience it as a strong emotional conviction, but the fact remains that they stay loyal to the proper method of making conclusions. And the strength of the conviction comes from the fact that they realize that if they desert this method of thinking about ethics, they desert their method of thinking about everything.
Seemingly, the man who acts regardless of a principle because he cannot think of a rational explanation why it should be otherwise is the one acting on reason, not on emotions. But this is not true.
He acts regardless of his implicit knowledge, which he did not insist on understanding. It would be the equivalent of dismissing the feeling of strong conviction that orange trees need water to grow because he is not yet sure what is the source of the feeling.
By far, the more difficult thing to grasp in ethics is why things like stealing, killing, etc' are experienced as bad as common sense. Why these things and not others?
The common sense behind that is that without those things life is not possible. If life is not possible, game over, there is nothing more to talk about.
If someone came to you and said "Why do you need your house? this is nonsense, I'm taking it away from you", you'd smack the bastard on the head. It would be clear to you that you need your house to survive, and that something that goes against your survival is bad. "Why do you need to be alive? What do you care if I cut your throat?" Such a question would be a sign of lunacy. It is clear to one that living is important, it is important, because without that there is nothing else to experience or regard as important.
So in these extreme cases which are easily observable to one, like a fist quickly approaching one's face, one understands implicitly that life is the standard of value - of regarding something as good or bad.
The difficulty is in generalizing cases like that to the rest of one's life. Something like lack of a law against stealing seems much further away and less tangible than a knife in proximity to one's throat.
This is why, in my opinion, people have a problem explaining why stealing and killing are wrong, even though they are experienced as a common sense thing.
A: "Why do we need laws against stealing and killing?"
B: "Because that is the only way we can survive as a society"
A: "And why is that significant in any way?"
B: "Because if it wasn't, you wouldn't be standing here, punk."
The last answer of B is the recognition that life is an ultimate value, one that makes all others possible. A question "why is living of any importance?" bypasses the fact that anything that is important is within one's life. No life, nothing to regard as important or non-important. It's like asking "why are questions important?" bypassing the fact that the questioner is asking a question.