The first principle of conservatism, according to Russell Kirk, is a belief in an enduring moral order. He writes:
Our twentieth-century world has experienced the hideous consequences of the collapse of belief in a moral order. Like the atrocities and disasters of Greece in the fifth century before Christ, the ruin of great nations in our century shows us the pit into which fall societies that mistake clever self-interest, or ingenious social controls, for pleasing alternatives to an oldfangled moral order.
Objective morality exists and can be known. To address the question of moral relativism, three distinctions need to be made, according to Mortimer J. Adler.
The first set is “description” and “prescription” or, “what is” and “what out to be.” How do we know if claims of prescription, (what we out to do) are mere preferences or something more? One group holds that moral knowledge (what we ought to do) is, in fact, knowledge, and not opinion. Others, however, as moral relativists, hold that prescriptions are opinions and not true knowledge.
Relativism and subjectivism, though different terms, are the hedonist’s favorites. The hedonist believes that the good and the pleasurable are one and the same.
However, contra the hedonist, many of the things we desire, which we call good, we find out later are bad for us. Cigarettes are one clear example that society originally thought was good, but later realized that it was only a perceived good, not an actual good.
An actual good, that is, a real and objective good, is one that is universal to all humans, at all times, and in all places. This would include the goods of truth, friendship, knowledge, food, water, and so on.
The second distinction corresponds to the first. A basic difference must be made between an inherent desire (say, for food) and an acquired desire, (say, caviar). These correspond with inherent goods, and perceived goods.
This leads to the third distinction. The basic difference between need and want, classically, underscored the difference between the previous distinctions. I need food, but I want caviar.
Thus, the relativist assumes that all desires are wants and are acquired. He thinks we are only discussing on the level of caviar and cigars. But the conversation needs to be understood to include inherently desirably goods like food and friendship broadly.
Some desires are not acquired but universal and inherent. All humans have a desire for food and friendship; it is problematic if they do not.
As Mortimer Adler points out, “we ought to desire whatever is really good for us.” This “ought” only applies to that which is inherently good, which is also an inherent desire. That is, we ought to desire (prescriptive statement) what is a natural desire, such as food, water, knowledge, etc. But acquired desires, such as caviar or information about something specific like, say baseball trivia, are wants and not needs, and thus, there is no ought.
Practically, this means that the general instead of the specific is what we are talking about. You cannot tell me I need to desire to learn about baseball, but you can tell me that I need to desire knowledge in general. You cannot tell me that I need to desire caviar, but you can tell me that I truly need, for my own good, to desire food and water.
Therefore, if you hold that a man who is using opioids to his own destruction, is someone who does not know what is really good for himself, (his health, good relationship with family and friends, etc) as opposed to merely a perceived good, (the pleasure of the high that comes from opioids) then you are appealing to the distinction between a real and true pleasure that is inherent, versus an acquired pleasure such as getting high.
Let’s review the distinctions that relativists and subjectivists fail to make.
Inherent goods correspond to needs, perceived goods correspond to wants. Inherent goods are like food, air, and water which apply to all humans at all times, and are thus objective goods. Perceived goods correspond to particulars, like caviar, Dom Pérignon, and Perla del Mar cigars. We can prescribe (command) what is a descriptive good if it applies to every person in every era.
But can’t we simply deny that water, food, and air are inherently good for humans? Mortimer J. Adler is again helpful.
He points out that the sign of an objective first principle is that its opposite cannot be rationally thought. That is, “the criterion of self-evidence…is the impossibility of thinking the opposite.” 
Could we really imagine saying that someone should not desire health, friends, family, knowledge, etc? He goes on, “it is impossible for us to think that we ought to desire what is really bad for us, or ought not to desire what is really good for us.” 
We ought to seek the truth, (and it is impossible for people to deny this prescription, this ‘ought.’ They can only try to undermine it).
Therefore, if we cannot rationally think that people should not desire health and happiness, food and water, friends and family, then we show that we don’t really believe, deep down, that all prescriptive statements are merely opinions and preferences.
The twenty-first century is, to echo Kirk, experiencing the hideous effects of a collapse of belief in transcendent moral truth. Indeed, 500 years before Christ, the atrocities and disasters of Greece foreshadowed what our century now finds; that to exchange belief in objective morality –a transcendent moral order– for clever sophism is indubitably to commit moral suicide.
Citations and References
- Russell Kirk, “Ten Principles of Conservatism”, https://kirkcenter.org/conservatism/ten-conservative-principles/
- Common sense still applies here — of course! — people being full, or sick, obviously, are to be taken into consideration. But the point still stands.
- Mortimer J. Adler, Six Great Ideas, p 126.
- Adler, Ibid.