Stony Brook University

good person. (ii) The second component of the logic of right consists of the logical
structures as a whole in relation to the logical structure of “traditional” logic, i.e., the
alethic logic of possibility and necessity. In other words, the normative logic of right
operates analogously, but independently, of traditional logic. This means that the moral
qualities themselves are the basis for a normative logic, that is, a logic for moral freedom
and virtue.
In order to understand what Leibniz is doing, it is best to begin with some
terminological clarifications, beginning with the “modes of right” (juris modalia). These
modes are permissible, forbidden, obligatory, and omissible. They are typically used in a
legal context to designate kinds of actions in relation to the law. 116 Thus, it is lawfully
permissible to do X, obligatory to do Y, and forbidden to do Z. Leibniz however uses
these modes in relation to a moral law, or rather, in relation to the definition of a good
person. Thus, for example, it is morally permissible to do X; morally obligatory to do Y,
and so forth, since X and Y are what the good person would do (i.e., perform some act of
rational love). In addition, the logical relations among these modes operate similarly but
differently from the “traditional” logical (or alethic) modes. 117 The alethic modes are
called possible, impossible, necessary, possible not. These are the four types of alethic
modal propositions of the Aristotelian square of opposition; but they are typically
reduced to two types: necessary and possible (or contingent). The alethic mode
categorizes propositions as either necessarily true or contingently true. For example, ‘A =
A’ is necessarily true; while, ‘the jurisconsult is happy’ is contingently true. The logic of
the modes of right and their relation to the alethic mode will be shown as we proceed. In
sum, what Leibniz is doing here is taking juridical terminology, placing it under moral
jurisdiction, so to speak, and giving it an a priori logic proper to norms of action, rather
than things or states of affairs.
We can now turn to the passages that begin Draft 5. 118 The first step is to see that
Leibniz begins with a definition of justice in terms of virtue. “Justice is the habit of
loving everyone.” 119 This definition is noteworthy for several reasons. As we saw, the
definition with which he had concluded his epagogic induction in Draft 4 was: “Justice is
the habit of loving others.” Thus the definition beginning Draft 5 represents a dramatic
broadening in scope: Justice is not merely the habit of loving some others, but all others.
However, we also noted that Leibniz seemed to define the just as “loving everyone.”
Therefore, since justice is the virtue of doing what is just, justice must be the habit of
loving everyone. It is important to connect this definition with another found at the very
beginning of Draft 6: “Justice is the habit (or constant disposition) of the good person;
116
Leibniz, who received his Doctorate in law at the age of 20 with his dissertation De Casibus Perplexis in
Jure (1666), was certainly familiar with this terminology. Quite possibly, the mode of obligation was first
recorded by Justinian (533 AD, Institutiones, Book 3 Tit. 13): “Obligation is a bond of law with which we
are bound by a necesssity of performing some act according to the laws of our state (obligatio est iuris
vinculum, quo necessitate adstringimur alicuius solvendae rei, secundum nostrae civitatis iura).”
117
Logicians refer to the “traditional” or Aristotelian modes as “alethic,” or “ontic,” or simply “logical”
modes. For consistency sake I will refer to the traditional modes only as ‘alethic.’ I will refer to Leibniz’s
juris modalia as either ‘modes of right’ or ‘deontic modes’. The term ‘deontic’ seems to have been coined
by G.H. von Wright (1951) or Ernst Mally (1926). See also von Wright (1971).
118
I have combined parts of Drafts 5 and 6 in a way that seems to me closest to Leibniz’s intentions and
which presents the most orderly argument.
119
A.6.1.465: “Iustitia est habitus amandi omnes.”
78