An investgation of natural laws, and, in parallel, a defence of ethical objectivism.The objectivity, to at least some extent, of science will be assumed; the sceptic may differ, but there is no convincing some people).
At first glance, morality looks as though it should work objectively. The mere fact that we praise and condemn people's moral behaviour indicates that we think a common set of rules is applicable to us and them. To put it another way, if ethics were strongly subjective anyone could get off the hook by devising a system of personal morality in which whatever they felt like doing was permissible. It would be hard to see the difference between such a state of affairs and having no morality at all. The subtler sort of subjectivist (or relativist) tries to ameliorate this problem by claiming that moral principles re defined at the societal level, but similar problems recur -- a society (such as the Thuggees or Assassins) could declare that murder is Ok with them. These considerations are of course an appeal to how morality seems to work as a 'language game' and as such do not put ethics on a firm foundation -- the language game could be groundless. I will argue that it is not, but first the other side of the argument needs to be put.
It is indisuptable that morality varies in practice across communities. But the contention of ethical objectivism is not that everyone actually does hold to a single objective sysem of ethics; it is only that ethical questions can be resolved objectively in principle. The existence of an objective solution to any kind of problem is always compatible with the existence of people who, for whatever reason, do not subscribe. The roundness of the Earth is no less an objective fact for the existence of believers in the Flat Earth theory.(It is odd that the single most popular argument for ethical subjectivism has so little logical force).
Another objection is that an objective system of ethics must be accepted by everybody, irrespective of their motivations, and must therefore be based in self-interest. Again, this gets the nature of objectivity wrong. The fact that some people cannot see does not make any empirical evidence less objective, the fact that some people refuse to employ logic does not make logical argument any less objective. All claims to objectivity make the background assumption that the people who will actually employ the objective methodology in question are willing and able. We will return to this topic toward the end.
Some people insist that anyone who is promoting ethical objectivism and opposing relativism must be doing so in order to illegitamately promote their own ethical system as absolute. While this is problably pragmatically true in many cases, particularly where political and religious rhetoric is involved, it has no real logical force, because the contention of ethical objectivism is only that ethical questions are objectively resolvable in principle -- it does not entail a claim that the speaker or anyone else is actually in possession of them. This marks the first of our analogues with science, since the in-principle objectivity of science coincides with the fact that current scientific thinking is almost certainly not final or absolute. ethical objectivism is thus a middle road between subjectivism/relativism on the one hand, and various absolutisms (such as religious fundamentalism) on the other.
The final objection, and by far the most philosophically respectable one, is the objection on that moral rules need to correspond to some kind of 'queer fact' or 'moral object' which cannot be found.
Natural laws do not correspond in a simplistic one-to-one way with any empirically detectable object, yet empiricism is relevant to both supporting and disconfirming natural laws. With this in mind, we should not rush to reject the objective reality of moral laws on the basis that there is no 'queer' object for them to stand in one-to-one correspondence with.
There is, therefore, a semi-detached relationship between natural laws and facts -- laws are not facts but are not unrelated to facts -- facts confirm and disconfirm them. There is also a famous dichotomy between fact and value (where 'value' covers ethics, morality etc). You cannot, we are told, derive an 'ought' from an 'is'. This is the fact/value problem.
But, as Hume's argument reminds us, you cannot derive a law from an isolated observation. Call this the fact/law problem. Now, if the morality is essentially a matter or ethical rules or laws, might not the fact/value problem and the law/value problem be at least partly the same ?
(Note that there seems to be a middle ground here; the English "should" can indicate lawfulness without implying either ineveitability, like a natural law, or morality. eg you "should" move the bishop diagonally in chess -- but that does not mean you will, or that it is unethical to do so. It is just against the rules of chess).
Sceptics about ethical objectivism will complain that they cannot be exactly the same because moral rules like "Thou shalt not kill" contain an 'ought', an irreducibly ethical element. Let's look at what sceptics about natural laws say: their complaint is that a law is not a mere collection of facts. A law cannot be directly derived from a single observation, but it is not constituted by a collection of observations, a mere historical record, either. A historical record is a mere description; it tells you what has happened, but a law tells us what will and must happen. A description gives no basis for expectation -- the territory does not have to correspond to the map -- yet we expect laws to be followed, if we believe in them at all.
I do not propose to answer this challenge in its own terms -- that is I do not propose to show that a collection of mere facts does provide all by itself the required lawfulness. On my analysis, all individual laws depend on a general assumption -- a meta-law or ur-law -- that the future will follow the same general pattern as the past. The sceptic will object that this has been assumed without proof. My reply is that each individual law is tested on its own merits. Since at least some laws are thus shown to be correct a-posteriori, the lack of a-priori proof of the meta-law is not significant.
My further contention is that there is a different meta-law that needs to be posited for ethical rules. Just as someone who is engaged in the business of understanding the natural world needs a basic commitment to the idea that nature has regularities, so someone needs a basic commitment to moral behaviour in order to be convinced by ethical arguments. Ethical arguments do not and cannot be expected to convince psychopaths, any more than mathematical arguments can be expected to convice the innumerate. Whilst it is essentially correct that an evaluative conclusion cannot be drawn directly from a factual premiss, such a conclusion can be drawn with the aid of a bridging prinicple, (which is of course just our meta-law) e.g
(2) is an example of a meta-law (or bridging principle or moral maxim), As ethical objectivism is a work-in-progress there are many variants, and a considerable literature discussing which is the correct one.