It is a good thing to have principles, so many people don’t. Principles serve as self-directed programmatic choices one has made or accepted. It is easy to understand therefore that some would regard principles as pre-judgments and offer reproof. Alice Cooper sang ‘we’ve got no class, got no principles, got no intelligence, can’t even think of a word that rhymes’.
Principles may arrive from others and conveyed as social values that one has accepted for various reasons. Immanuel Kant wrote sapere aude– think for oneself. René Descartes’ earlier had written a philosophical investigations on epistemology were he resolved to investigate first principles of knowing, of self-awareness; perhaps Kant thought to improve on that and to consider perception and objects technically rather than introspectively- objectively rather than subjectively if that differentiation were possible… Kant wrote The Critique of Pure Reason trying to do so.
Agencies of socialization may train one, or indoctrinate, their own ethical values in subjects; i.e. television. Television watchers presently encounter one commercial where a famous lesbian appears extolling the virtues of evolution following a funny video story about stone-agers trying to cross a bay without a boat and being eaten. The obvious purpose is to promote homosexuality as an evolutionary, progressive devise. The values of the rich are promoted through the television commercials and content they can afford to put out. Some of those values and principles may be at cross purposes with others you have learned.
The moral and value principles in the commercial showcase evolution as social change, and lesbianism as an example of positive change. The unstated premise of atheism being rational is implicitly inferred from the context. What isn’t mentioned about evolution is that not all change is good-for-all.
An example of evolutionary harm might be that of Nazi Germany’s final solution being harmful to European Jews. If a Chinese bio-lab invents a virus that escapes and kills all human life on Earth except for independent voters in the U.S.A., that would be bad for everyone except possibly the independent voters. Neither can evolution be set against Christian beliefs for there are Christians that believe the book of Genesis describes God evolving the Earth on his own better than ours time.
Principles are abbreviated, encapsulated forms for behavior and for making live moral or other kinds of choices without needing to rethink those on-the-spot. Sometimes that kind of time for careful reflection on principles doesn’t exist. Consider the philosophical ethical thought problem of a fellow forced to choose between switching a runaway train onto a track with one baby tied to the rail or let it go ahead to crash into a bus full of Democrats that is stalled on the track- if he had a moral principle thing about it he could act decisively. If he stopped to think about the moral issues the train might speed right on past while he was thinking about it.
There is a difference between abstract principles and principles actually used and accepted as worthwhile for-oneself. Some authorities; Biblical for example, offer moral instructions or principles that can save a lot of suffering learned through experience, even so it is worth thinking about accepted moral principles to determine for-oneself if they are reasonable, if opportune.
If one reads a book on outboard motor mechanics that describes particular principles of small engine repair and those principles become your own, and one day you need to repair a broken outboard motor on the high seas, and discover that the book obviously had bad advice and actually was written by a poet, it is likely that you would discard that set of principles for repairing an outboard motor and look for something else if you survive rowing to safe harbor. Untested moral principles that are abstract can fail when put to the test. One sees the temptations of Christ that were well met; not every human does so well in applying or understanding moral principles to actual circumstances if they need to.