As early as around 1720, the emergence of a new and fully secular moral philosophy based on Spinozistic premisses was already intimately linked to a republican politics in France, as is apparent especially from the writings of Boulainvilliers, Du Marsais, and Meslier, albeit in Boulainvilliers's case an aristocratic rather than democratic republicanism. A republican politics was clearly integral, even essential, to the purely secular moral stance adopted by these writers. According to Du Marsais, the psychology of life without religion in the conventional sense leads the ideal man, le philosophe, to embrace probity and uprightness and the reputation of being upright: 'c'est la son unique religion.' 'La societe civile,' and its requirements and well-being, argues Du Marsais, become for him the only divinity on earth which he recognizes, and this divinity he cultivates and honours by giving an exact and conscientious attention to his social responsibilities and through his resolve to be a useful member of society. The kind of materialist atheism represented by Du Marsais necessarily creates a context in which the well-being of society becomes simultaneously both the highest political good and the unalterable basis of morality and true 'piety.'
By contrast the man of 'faith' in the usual sense, or the 'superstitieux,' as Du Marsais prefers to call such a person, even when raised to positions of the highest responsibility in society, still considers himself in some sense a stranger here on earth, a temporary visitor whose chief responsibility is to transcendent beings, values, and aims rather than the worldly well-being of men, a theme later much expanded on by Diderot. Also, Christian disdain for worldly success, prosperity, and social standing—whatever religious justifications such attitudes may acquire—is, in the end, contrary to what is needed to render a society happy and flourishing. In particular, Du Marsais condemns the ideal of 'poverty' as antisocial and counterproductive, since poverty deprives us of the well-being which makes worthwhile pleasures possible: 'elle bannit loin de nous toutes les delicatesses sensibles et nous eloigne du commerce des honnetes gens.'
Reaffirming Spinoza's principle that the more one lives according to reason directed towards one's own self-interest, the more one is fitted for life in society, Du Marsais holds that the dishonest man is as opposite to the true image of the philosophe, conceived as the ideal man of reason, as is a simpleton with scant understanding. Managing the passions, the philosophe may be somewhat inclined towards sensual satisfaction and pleasure but never towards crime or antisocial activity. His cultivated reason leads him to display his independence in such a way as never to cause strife or disorderly conduct. The philosophe is thus an honest man, holds Du Marsais, 'qui agit en tout par raison, et qui joint a un esprit de reflexion et de justesse les moeurs et les qualites sociables' [who acts in everything according to reason joining a spirit of reflection and justice with morality and the sociable qualities].
Since the republic's laws are the only enforced and politically sanctioned set of guidelines as to what is 'good' and 'bad' in human conduct, they are also if not the foundation (which is reason) certainly the prop and chief support of morality. In this way, the republic's legislation becomes the root of moral obligation, allegiance, and duty, indeed the only valid object of public reverence and obedience, while, conversely, morality in the Radical Enlightenment's sense and, therefore, the 'common good' as defined by Spinoza, Bayle, and Diderot, become the yardstick by which to judge political events and laws old and new as well as suggested amendments. Since there are no divine commandments, according to the Spinozists, or reward or punishment in the hereafter, Heaven and Hell being—as van Leenhof dared affirm (with disastrous consequences for himself)—purely worldly states of mind, there is no other way to uphold order, repress crime, and instil discipline than by means of worldly rewards and penalties proclaimed and enforced by the state and its legislature. This was very much also Mandeville's view.
An important consequence of the claim that human rewards and penalties in the here and now count for more than revealed religion, allegedly divine commandments, and the promise of Heaven and threat of Hell, when it comes to civilizing and disciplining men, and repressing aggression and crime, is a new urgency for the secular polity to be stable, well organized, and efficient. In a striking passage of Den Hemel op Aarden, van Leenhof affirms, much like Du Marsais later, that rulers have learnt from experience that theological doctrines instilling dread of divine chastisement in practice exert little effect on hardened criminals and reprobates. Such men mock 'divine' admonitions and entirely set them aside when embarking on their careers of pillage, murder, and other 'mad and bestial passion.' They can be effectively restrained, he contends, only by credible legal deterrents and vigorous policing.
The magistrate who understands what is 'good' and 'bad' for society, he says, 'can do more to curb the godless than all the preachers together', the sovereign power having 'long arms and a thousand eyes through its officials and loyal subjects.' Crime flourishes, he says, where government is weak and the law inadequately enforced: for even in a well-regulated republic only a very few people are truly 'free' and virtuous, that is exercise their own reason adequately, most people obeying the law, as Mandeville later also affirmed, not through love of virtue but merely through fear of punishment. Yet whether government is strong or weak, it is the law-abiding and those who revere the law who are the most 'rational' and, whatever priests may say, also the most 'pious,' and this has always been so.
What Mandeville adds to democratic republican theory was his insight that in inculcating obedience to the law, it is not just fear of penalties, and hope of reward, which count but also, and perhaps even more, the mechanics of 'pride' and 'shame'. Preoccupation with 'honour' and 'dishonour,' he thinks, is a natural impulse in men which can be effectively exploited to discipline them and spread the legislators' notions of 'good' and 'bad' through society. Hence, 'it was not any heathen religion or other idolatrous superstition that first put man upon crossing his appetites and subduing his dearest inclinations,' he assures readers, 'but the skilful management of wary politicians; and the nearer we search into human nature, the more we shall be convinc'd that the moral virtues are the political offspring which flattery begot upon pride.'
Morality, for these writers, is 'relativistic' only in the restricted sense that there is no God-ordained 'good' and 'evil' and that the criterion of 'good' and 'bad' is what rational men judge beneficial, or not, to Man and what society decides—in van den Enden and Spinoza preferably through democratic assemblies—promotes the 'common interest'. But this purely secular, quasi-utilitarian morality is at the same time universal, and eternally the same, since the 'general good' is as reason dictates and reason, hold Spinozists, is one, all-embracing and unchanging. In this way, the ethical 'relativism' of Spinozist republicanism yields a single moral code invariable and universal, based on reciprocity, equality, and personal freedom, something wholly unlike (and opposed to) the moral relativism of the late twentieth-century Postmodernist 'difference.'
Mandeville, like Hobbes and Spinoza, rules out freedom of the will, arguing that Man is a being determined regarding both motives and actions. Furthermore, it is precisely this principle that he, like Spinoza and van Leenhof, employs to justify his view that rewards and penalties enacted by the state are the best way to correct, discipline, and civilize men's behaviour. Self-interest is what persuades the criminally inclined to curb their natural unruliness and defer to the law in a well-ordered state. 'There is nothing,' asserts Mandeville, 'so universally sincere upon earth, as the love which all creatures that are capable of any, bear to themselves: and as there is no love but what implies a care to preserve the thing beloved, so there is nothing more sincere in any creature than his will, wishes and endeavours to preserve himself.' This, he explains, is 'the law of nature, by which no creature is endowed with any appetite or passion but that which either directly or indirectly tends to the preservation either of himself or his species.' Hence, in Mandeville, no less than Hobbes and Spinoza, the fact that Man is bound to conserve his being, and satisfy his desires, means he can be systematically deflected and deterred from antisocial conduct only by credible warnings of punishment and exposure.
Mandeville's notorious thesis, detested by so many eighteenth-century commentators, including Hume, that virtue is not innate or natural in Man and cannot be taught, is his equivalent of Spinoza's 'infamous' doctrine that 'virtue' is really equivalent to power and is always selfish in motivation and Morelly's claim there are no vices in the universe except avarice. Instead of 'virtue' as something inculcated or learnt, Mandeville substitutes the Spinozistic principle that 'whoever will civilize men, and establish them in a body politick, must be thoroughly acquainted with all the passions and appetites, strengths and weaknesses of their frame, and understand how to turn their greatest frailties to the advantage of the publick.'
Accordingly, respect for the law, integrity, and conscientiousness among office holders and state officials should never be entrusted to what Mandeville calls the 'virtue and the honesty of ministers', even in the Dutch Republic which he rated distinctly higher than the monarchies of his day, being a state that afforded citizen a more effective rule of law, order, and justice than did the latter. The United Provinces cultivated the public interest, according to Mandeville, by means of 'their strict regulations concerning the management of the publick treasure, from which their admirable form of government will not suffer them to depart: and indeed one good man may take another's word, if they so agree, but a whole nation ought nevel to trust to any honesty, but what is built upon necessity; for unhappy is the people, and their constitution will ever be precarious, whose welfare must depend upon the virtues and consciences of ministers and politicians.'
Hence in Mandeville, as in Spinoza, the level of probity and respect for the laws and 'common good' among government officials, in a particular regime, stems not from the personal inclinations of office-holders which, broadly speaking, remain always the same, and are all equally liable to corruption, but from the effectiveness otherwise of regulations, checks, and penalties devised to ensure accountability and respect for the law. Similarly, wrongdoing by individuals is checked only by good government and well-made laws just as, conversely, misconduct thrives on badly framed laws and official neglect.