For me, as for some of the other posts on here, the Golden Rule pretty much provides my moral compass. But I also acknowledge that most of my moral and ethical positions have been formed in social contexts, including my education, which included reading guys like Kant, as one person mention above. For example, it's because I've been a teacher, and witnessed so much cheating, that I tend to view cheating as such a serious offense. My positions on things like same-sex marriage have evolved as I've gotten older, more educated, and have become friends with many gay people. I've come to view poverty as a moral issue after teaching and living in one of the most impoverished regions in the United States. The point I'm trying to make is that I think our experiences and interactions with others shape our ethics as much as any immutable "truths" that are out there. Maybe some people's sense of morality is less fluid than mine, but I suspect that none of us forms our ethical outlooks in a vacuum.
I learned my personal sense of morals through my church, my family, and my community of social relationships with others. Because I am a Christian from a Christian background, the way in which I learned the summary of the basis of my sense of right and wrong was phrased (depending upon the version of the Bible you used), "Do unto others as you would have them do unto you." (Matt. 7:1)
The reassurance I find is in realizing how many other religions around the world deliver this same message. The basic human understanding that all persons should be respected and treated with justice in the same way that you would want to be thought of and treated yourself is the universal basis of all philosophies of right and wrong. When people treat each other as they would wish to be treated themselves, the basic goodness of us all comes out naturally.
Another view of morality is that it is a community safety or social regulation system.
This view sees morality as defined by societies, often loosely and abstractly and sometimes through law and written code, with a purpose - to make living in a community possible; to protect interests of the group by balancing the interests of individuals via social regulation.
This means that as individual interests change and group interests change, so do moral concepts/moral codes. Right and wrong can be seen as having an intrinsically practical origin, which explains the flexibility of these concepts under changing conditions. (ex: Killing in peace time is wrong. Killing in war is acceptable.)
A recent book makes this argument:
But Prof Marc Bekoff, an ecologist at University of Colorado, Boulder, believes that morals are "hard-wired" into the brains of all mammals and provide the "social glue" that allow often aggressive and competitive animals to live together in groups.
My own sense of right and wrong is generally based on the moral codes taught to me by my parents and grandparents (especially my Victorian-era grandmother) and the religious beliefs passed down to me. Throw in the importance of the law of the land and, though there are often conflicts, these are the guidelines that I use as a basis of deciding what is right and wrong.
I definitely agree with the above post, but would also suggest that morality develops very early on in child development. I remember seeing a segment on 60 Minutes in which researchers tested infant responses to both bad and good behavior. The researchers used animal puppets to play-act scenes of good behavior like sharing or bad behavior, in which a rabbit puppet stole a toy away from a kitty puppet. When presented later with the puppets, the infants invariably looked away from or frowned at the bad rabbit puppet who stole the toy, while the babies smiled or reached for the nice puppet who demonstrated sharing. The amazing results from this study absolutely make me believe that some sense of morality is innate, that humans are pre-coded with a sense of right and wrong.
Rigth and wrong come from our sense of empathy. It is an outgrowth of our ability to imagine and identify with the emotional and physical state of others. Because we are able to empathize, we sometimes experience the suffering we cause in others. That shared experience leads to our sense for right and wrong.
The concept of "right" and "wrong" are (religion aside) an entirely human invention. Animals have no concept of morality; they act as their instincts dictate, regardless of the effect on others. Even highly-intelligent animals, which may seem to be acting according to conscious thought, are simply acting out their evolved instincts.
Humans are different. We look past the action and its immediate outcome to judge the "correctness" of consequences. We rationalize, judge, justify, and excuse, but we always act according to an innate feeling of morality. Our morals are defined from youth, shaped by our parents and society, and as we develop critical thinking, we can change what we consider moral correctness.
Religion usually has a defined set of correct and incorrect actions; this is set by whatever higher power is defined as supreme. Man's actions, then, are material reflections of the greater good of spirituality.
From a humanist perspective, morality is defined by the individual's effect on society; actions which damage others are deemed immoral. Here, "correct" actions are defined by philosophy and ethics, all of which are based in societal and cultural development; an older, more-refined culture will usually have more complex ideas of morality than a younger or less-refined culture.
Personal morality, then, depends on what is accepted as a basis. If you are religious, your morality is defined by the spiritual works of that religion. If you are not religious, you are free to develop your own moral philosophy based on experience, knowledge, and study of philosophical antecedents.
This is, of course, an issue that has intrigued philosophers and others through the ages. There are many schools of thought. Religious people might say that God determines what is right and what is wrong. Utilitarians would say that the right action is that which has the best results in terms of making people happy. Kant would say that something is right if it is done for the right reason; if it is done according to some rule that would make a good universal law.
I personally would pick Kant’s formulation above the other two. I think that we human beings can never predict the consequences of our actions well enough for that to be the basis of right and wrong. I do not think that blindly following what a given religion says is God’s will works either. I am left with the idea that we act rightly when we act based on good premises, even if our actions end up going badly.