None but those of the happiest mould are capable of suiting, with exact justness, their sentiments and behaviour to the smallest difference of situation, and of acting upon all occasions with the most delicate and accurate propriety. The coarse clay of which the bulk of mankind are formed, cannot be wrought up to such perfection. There is scarce any man, however, who by discipline, education, and example, may not be so impressed with a regard to general rules, as to act upon almost every occasion with tolerable decency, and through the whole of his life to avoid any considerable degree of blame.--Adam Smith, The Theory of Moral Sentiments. 3.5.1.
But, at the same time, we should remember that we are subject to God's authority, as clay to that of the potter, who of the same lump makes some vessels unto honour, and others unto dishonour.--Spinoza, Political Treatise 2.22.
Spinoza and Adam Smith are drawing on famous Biblical imagery:
Does not the potter have the right to make out of the same lump of clay some pottery for noble purposes and some for common use?--Romans 9.21.+
At first sight, Spinoza follows Paul more closely than Smith. Even though Smith's chapter has the suggestive subtitle, "the general Rules of Morality, and that they are justly regarded as the Laws of the Deity, in the quoted passage he does not mention God. By contrast, Spinoza uses the clay/potter imagery to assert God's authority to let the same human nature be expressed in different morally salient ways. Even so, where Paul has 'common use,' Spinoza changes and deepens the moral valence by deploying 'dishonour.'
In immediate context of Romans, Paul's point is to claim that even bad people (e.g., Pharaoh) have an assigned providential role to play. This is meant to supply an answer to an argument from the problem of human evil (against, say, the justness or even existence of God). In Paul's theodicy, we play a role in another's grand performance; while we may complain about the script assigned to us, what matters is the quality of the play, and we need to keep faith in the artistic vision of the playwright. It is no surprise, then, that Romans 9 concludes in a defense of faith against works. It's not, as Spinoza observes in a footnote to the Theological Political Treatise, like we have a choice in the matter, in the Pauline universe: God "has mercy on whom He will, and that men are without excuse, only because they are in God’s power like clay in the hands of a potter."
Now, as is well known, Spinoza is no friend of providence. Even so, when he returns to commenting on Romans in the context of the Political Treatise, Spinoza opts for the more modest, skeptical claim that the course of nature is unknown (which, say, a skeptical theist may also affirm).* He hastens to add that the dictates of reason urge respect of religion [religionem concernunt]. So, Spinoza does not, as some of his modern atheist admirers suggest, advocate a secular rejection of religion, but he promotes (undoubtedly suitably reformed and controlled) religion in which the worship of God proceed with sincerity [integro animo amat]. A political feature of this reformed religion is revealed in the paragraph before: "reason teaches one to practise piety, and be of a calm and gentle spirit, which cannot be done save under [state] dominion." The role of religion is to generate political obedience (to a state that is itself an object of religious veneration) and this, in turn, allows us to become (to use anachronism) more relaxed.**
So, Paul and Spinoza use the pottery/clay analogy and agree that God's power is compatible with people acting nobly and not-so-nobly. Smith, by contrast, uses the analogy not to address the problem of evil; rather he deploys it to express, in one sense, a more elitist (or perfectionist) and hopeful thought: he insists that perfectly virtuous people are genuinely possible in the real world (while Spinoza denies this in the very same chapter).*** More important, Smith thinks that everybody can be sufficiently moral in the right institutional context ("discipline, education, and example.")++ I would claim there is no doubt that Smith sees it as one of his philanthropic tasks to promote such institutions. As Susan James has argued, such institution-building conducive to everybody's moral agency is also Spinoza's position.
While Spinoza promotes religious toleration, ultimately he thinks this moral project requires state control over religion. By contrast, among such disciplinary, moral institutions, Smith advocates disestablishment of religion and true freedom of religion (see Fleischacker on Smith).
+I ignore here the pre-history of the image in Isaiah.
*This also fits with other features of Spinoza's version of rationalism which, I argue, is epistemically modest about our knowledge of empirical nature.
**It may in Spinoza's system also be the road to salvation and blessedness for the non-philosophers.
*** Earlier in the chapter, he treats original sin as evidence for this claim: "that it was not in the first man's power to make a right use of reason, but that, like us, he was subject to passions." (PT 2.6; recall here, here, see also links there).
++On the role of discipline, see Fonan Forman.