We talked about who Grotius was, why he wrote The Rights of War and Peace, his method of moral philosophy, and his understanding of the terms “war” and “right.”
Grotius was convinced that there are natural standards of right and wrong and, in particular, that these standards govern the use of violence. By “natural,” I mean that the standards are not created by human beings; they are not artificial.
Grotius took himself to have two kinds of opponent. On the one hand, there are those who think that moral standards are conventional, such that each society has its own standards of right and wrong much as each society has its own system of laws. You can find this sort of view articulated by Thrasymachus, Glaucon, and Adeimantus in Plato’s Republic or by the American Anthropological Association in its 1947 “Statement on Human Rights”. Grotius used Carneades as a representative for this position.
As Grotius described his views, Carneades held both that the standards of right and wrong are conventional and that they are fundamentally based on considerations of interest. That seems to mean two things. First, the historical explanation of why societies developed standards of right and wrong is that those standards served the interests of their members. Second, there is no reason to comply with the standards when doing so runs contrary to your interests (Grotius 2005, 79).
In addition to conventionalists like Carneades, Grotius also disagreed with pacifists. These were Christian thinkers who maintained that God did not allow human beings to use force at all. Grotius hoped to chart a middle path between those who thought there were no natural standards of right and wrong at all and those who thought the standards both exist and rule out the use of force. He would show that war is allowable but that there are rules governing both when war is permitted (book 2) and how it can be waged (book 3).
Grotius’s method is slightly different from what you are probably familiar with. Grotius wanted to give a systematic treatment of the laws of nature (Grotius 2005, 107). His system involved showing that three different sources all agreed on a common set of laws: nature, divine command, and human custom (Grotius 2005, 75). By contrast, most of the moral and political theories you have probably read attempt to derive a set of rules from a single set of premises, such as the doctrine of the mean, the principle of utility, the categorical imperative, or the original position. They look for a systematic account of the sources of the rules. Grotius, by contrast, drew on an eclectic mix of sources because he was chiefly interested in the rules that, he thought, they all converged on.
Grotius has two answers to Carneades. First, people are naturally sociable; they aren’t just self-interested (Grotius 2005, 86, 93f). Accordingly, the laws of nature are not variable; they uniformly forbid behavior that is repugnant to human society. Second, there are conventionally accepted rules of international law; laws are not just limited to different societies (Grotius 2005, 94).
Graham asked a question that I’m pretty sure was on everyone’s mind: what’s the difference between Grotius’s position and Carneades’s?
After all, if we are naturally sociable, it will be in our interest to support rules that preserve societies (in fact, this will probably be in our interest even if we are not especially sociable). And Grotius’s second point is compatible with holding that all laws are conventional in origin; it just states that Carneades missed one kind of conventionally defined law: international law.
One difference between Grotius and Carneades is that Grotius was committed to holding that the laws of nature have a divine origin. But it is legitimate to ask how significant a difference that is. As Grotius himself put it, “all we have now said would take place, though we should even grant, what without the greatest Wickedness cannot be granted, that there is no God, or that he takes no Care of human Affairs” (Grotius 2005, 89). The exact meaning of that is not perfectly clear, but it suggests that nature and convention alone should be enough to at least tell us what the laws of nature are.
I proposed a distinction that I think Grotius might have had in mind between what I called narrow and wide interest. Our narrow interests consist in things that benefit ourselves: money, power, and so on. Our wide interests consist in things we care about, including other people. My proposal is that Grotius thought that Carneades was saying that we only have narrow interests while Grotius thought we have wide interests in human society.
I suppose another difference between them is that Grotius believed our interests are all similar enough that the laws necessary for human society will be the same for every society. If so, there will not be as much variation from society to society as Carneades might have suggested.
In the end, though, Carneades and Grotius will be pretty close. Both will say that laws serve our interests. And Grotius will not really have shown that someone who does not have wide interests in society has any reason to comply with the laws of nature.
According to Cicero, war is “a Dispute by force”; according to Grotius, “War is the State or Situation of those … who dispute by Force of Arms” (Grotius 2005, 134). (No, I’m not sure what adding “state and situation” adds.)
“Right” has three different meanings.
“This Sociability, which we have now described in general, or this Care of maintaining Society in a Manner conformable to the Light of human Understanding, is the Fountain of Right, properly so called; to which belongs the Abstaining from that which is another’s, and the Restitution of what we have of another’s, or of the Profit we have made by it, the Obligation of fulfilling Promises, the Reparation of a Damage done through our own default, and the Merit of Punishment among Men.” (Grotius 2005, 86)
“1. A Power either over our selves, which is termed Liberty; or over others, such as that of a Father over his Children, or a Lord over his slave. 2. Property … 3. The Faculty of demanding what is due, and to this answers the Obligation of rendering what is owing.” (Grotius 2005, 138–39)
The second one is the most interesting. As Michael put it, it identifies a right as something that a person has and uses. The other two definitions treat the word “right” as meaning something more like “the right thing to do,” with the first restricting itself to what is just and the third including all of the considerations that go into determining what is the right thing to do (e.g. would it be nice, generous, and so on).
Grotius, Hugo. 2005. The Rights of War and Peace. Edited by Richard Tuck. Indianapolis: Liberty Fund.