Institutes of Divine Jurisprudence, with Selections from Foundations of the Law of Nature and Nations. Christian Thomasius
not, though Thomasius also believed that following the fall from grace the human will was not always able to exercise its freedom unimpeded. Ever since original sin, the human passions interfered with the operations of the will and distorted its choices. But this interference was never so strong that humans ceased to be responsible for their actions.17
God’s commands in natural law were not arbitrary, but his reasons were not fully evident to humans. It was only clear that, having created human nature as it was, God must have wanted humans to act according to the principles of natural law, as they were known from the empirical observation of humankind. Thomasius placed great emphasis on the inscrutability of God’s mind to human understanding. This was one important respect in which he distinguished his natural law theory from that of opponents such as Valentin Alberti. Alberti believed that the content of natural law was not the product of divine commands but founded on eternal truths in the mind of God.18 The moral principles of natural law were not identical to these truths, but they were derived directly from them and, therefore, were just. They were not known to humans on the basis of empirical observation and reflection but were innate and part of the so-called imago divina, the divine image that God had implanted in humans when he created the world.19 Yet Alberti also said that these moral principles had been present in their full strength and clarity only in the state of innocence, before original sin. Following the fall from grace, they were blurred and obscured, and humans depended on divine revelation to supplement their imperfect knowledge and understanding of them. In particular, it was the Decalogue, given by God to the Israelites after their exodus from Egypt, that summarized the central precepts of natural law.20
The first of Thomasius’s main objections was that Alberti’s theory of
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the imago divina and the derivation of natural law from eternal truths implied a continuity, which did not exist, between human understanding and the mind of God. The two differed in kind, not just in degree, and the distance between them was insuperable.21 Humans should therefore not dare to speculate about the ideas in God’s mind. The grounds for God’s decisions are inscrutable, and humans must not assume that their moral reasoning and that of God’s are comparable and based on similar principles. The precepts of natural law were binding because they were known to be the commands of God, who was the rightful superior of humankind, not because they conformed to particular eternal truths. Thomasius also argued that Alberti’s theory of eternal rational truths appeared to subordinate God’s will to an external standard of morality: it implied that there were rules independent of and superior to God, which God had to adhere to, thus restricting his freedom and power.22 Alberti replied that this standard according to which God acted was part of his own intellect, and thus it constituted no external restriction on him. To say that God acted according to principles that were part of himself, and not arbitrarily, did not imply that his freedom or his power was limited.23
Thomasius’s natural jurisprudence in the Institutes was thus largely, if not completely, Pufendorfian. Yet natural law formed only one-half of the “divine jurisprudence” referred to in the full title of his work. The other half was divine positive law, and one of Thomasius’s main concerns in the Institutes was to clarify the relationship between natural and positive divine law. As we have seen, Valentin Alberti argued that the main example of divine positive law, the Decalogue, was a republication of the laws of nature, which had been erased or at least obscured by the effects of original sin. Thomasius’s view in the Institutes was that divine positive law was not needed to reconstruct and understand the main principles of natural
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law. It was, however, important for other reasons, in particular because it provided guidance on certain temporal matters on which natural law was silent.
The most significant temporal matter, judging by the space devoted to it in the Institutes, was marriage.24 Thomasius had examined the relevance of natural law for marriage in his disputation De crimine bigamiae of 1685, where he had concluded that the prohibition of bigamy had to be based on divine positive law because natural law did not offer any clear arguments against it.25 In the Institutes Thomasius discussed at length the laws banning the different forms of polygamy and limiting marriages between relatives. Thomasius’s conclusion there, too, is that these restrictions rest on divine positive law, not natural law, which is insufficient to explain them.26 To the extent that divine positive laws are directed toward the affairs of temporal society, they stand in no need of interpretation by theologians. Jurists are capable of understanding and applying them, like the precepts of natural law or human positive law, and in so doing do not need to seek the advice of theologians.27 This right of jurists to interpret Scripture on matters relevant to temporal law was part of Thomasius’s argument against clerical authority more generally, which he continued and expanded in the following years, especially after he moved to the territories of the Elector of Brandenburg and began to teach at the University of Halle.28 Here Thomasius also began to rethink his natural jurisprudence, a process that led to his second main work on natural law, the Foundations of the Law of Nature and Nations, published in 1705.
Foundations of the Law of Nature and Nations (1705)
An important change in Thomasius’s natural jurisprudence concerned the relationship between moral and physical qualities. In the Institutes he
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had argued that these two types of qualities were distinct and separate: whether a particular action or condition was deemed morally good or evil depended on the moral value imposed on it by a superior, not on its physical attributes. In the three books of the Foundations Thomasius changed his mind and argued that moral value was not something that was attached by an act of will to a morally indifferent nature. Instead, moral qualities were a species of natural qualities, and moral philosophy itself formed part of natural philosophy, or “physics.”29 In particular, actions were morally good or bad, depending on their natural effects. Moral actions tended naturally to further the well-being and happiness of the agent and others, while immoral actions caused infelicity and ill health. This was so because God had created nature in such a way that its ordinary course reinforced moral conduct.30
These natural advantages and disadvantages in temporal life could be considered a form of divine rewards and punishments, though Thomasius said that they were not comparable to the sanctions threatened by a human legislator.31 In particular, they were not sufficiently obvious to deter humans from breaking the law of nature, because “every [human] punishment must be inflicted visibly, but the evils which God has ordained for the transgressors of natural law come secretly, in such a way, that the connection of the evil with the sin is not evident, even if the evil itself is evident.”32 The natural consequences of moral and immoral actions were thus more similar to advice than to coercion.33 God had no reason to compel humans to act morally by threatening them with punishments, because he derived no advantage from their obedience. Also, if the disadvantages of immorality were so clear and powerful that they deterred everyone from violating natural law, there would be no merit in being virtuous. A human legislator, on the other hand, had a clear interest in forcing his subjects
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to be obedient, regardless of whether they did so only out of fear. Related to this new idea of punishments was another change in the Foundations, Thomasius’s rejection of the notion of a divine positive law: because God was not comparable to a human legislator, who enforced his laws with punishments, the concept of a divine positive law, which was analogous to human positive law, made little sense. Divine positive law, according to Thomasius, had been the invention of self-interested clergymen, who had tried to use their authority in questions of scriptural interpretation to exercise influence on temporal matters, such as legal cases concerning marriage.34
Thomasius also completely changed his notion of the freedom of the human will and its relationship to the human intellect. His previous idea of an “indifferent” will, he now argued, was wrong, for if the will was equally indifferent to all available courses of action, it