For ‘tis evident, that if a person full-grown, and of the same nature with ourselves, were on a sudden transported into our world, he wou’d be very much embarrass’d with every object, and would not readily find what degree of love or hatred, pride or humility, or any other passion he ought to attribute to it. The passions are often vary’d by very inconsiderable principles; and these do not always play with a perfect regularity, especially on the first trial. But as custom and practice have brought to light all these principles, and have settled the just value of every thing; this must certainly contribute to the easy production of the passions, and guide us, by means of general establish’d maxims, in the proportions we ought to observe in preferring one object to another. (Hume Treatise 2.1.6)
Suppose a person, though endowed with the strongest faculties of reason and reflection, to be brought on a sudden into this world; he would, indeed, immediately observe a continual succession of objects, and one event following another, but he would not be able to discover any thing farther. He would not, at first, by any reasoning, be able to reach the idea of cause and effect; since the particular powers, by which all natural operations are performed, never appear to the senses; nor is it reasonable to conclude, merely because one event, in one instance, precedes another, that therefore the one is the cause, the other the effect. Their conjunction may be arbitrary and casual. There may be no reason to infer the existence of one from the appearance of the other. And in a word, such a person, without more experience, could never employ his conjecture or reasoning concerning any matter of fact, or be assured of any thing beyond what was immediately present to his memory and senses.--David Hume Enquiry Concerning Human Understanding, 5.3).
Could we conceive a person of the soundest judgment, who had grown up to maturity, and whose imagination had acquired those habits, and that mold, which the constitution of things in this world necessarily impress upon it, to be all at once transported alive to some other planet, where nature was governed by laws quite different from those which take place here; as he would be continually obliged to attend to events, which must to him appear in the highest degree jarring, irregular, and discordant, he would soon feel the same confusion and giddiness begin to come upon him, which would at last end in the same manner, in lunacy and distraction. Neither, to produce this effect, is it necessary that the objects should be either great or interesting, or even uncommon, in themselves.--Adam Smith, "The History of Astronomy."
Jeff Bell has returned to regular blogging! (Hurray!) Recently he wrote a wonderful series of posts on Hume, Spinoza, and Deleuze in which he called attention to the two passages from Hume quoted above. One striking claim in the passage from the Treatise that Bell does not remark upon is Hume's claim that "custom and practice...have settled the just value of every thing." (Hume repeats the claim with the same thought experiment in his dissertation on the passions.) It is tempting to see in this some kind of long run equilibrium claim. Even so, one doesn't need to know Hume's account of taste (combined judgments of true judges set value), his account of economics (value is established in the market), or his mistrust of theodicy, to find this is a bit surprising. For at the very start of the Treatise, Hume had bemoaned that metaphysics was being unfairly undervalued (despite there being "just value for every other part of literature") by the learned! So, Hume knows that custom and practice cannot be expected to produce just values in philosophy.
In his post, Jeff recognizes that there are important differences between the two thought experiments in Hume. But it is striking that Adam Smith, too, must have seen some connection between the two. Because in the thought experiment that I quote above he combines elements of the Treatise account (sudden transportation) and the first Enquiry (the thought experiment is, in part, about the relationship between habituated experience of a certain worldly order and the development of causal relations in the imagination [see also first Enquiry, 4.8]).
Of course, instant (Swapman-like) creation and instant transportation to other planets are both impossible. But this does not mean that the idea that “some other planet, where nature was governed by laws quite different from those which take place here” did not have the backing of highest scientific authority of time. For, we find in Newton’s Opticks:
it may be also allowed that God is able to create particles of matter of several sizes and figures, and in several proportions to space, and perhaps of different densities and forces, and thereby to vary the laws of nature, and made worlds of several sorts in several parts of the universe. (Query 31)
Anyway, there are two aspects about Smith’s thought-experiment that are crucial to Smith’s more philosophy more generally, and where he develops what may well be latent in Hume's thought: first, sound judgment seems to consist in having the right kind of habits, that is, ones expectations match the world’s natural order. Here it is left unclear to what degree we have any control over these habits. At any rate, for Smith, in a properly functioning person there is a reciprocal relationship between the habituated mental anticipations and sound judgment.
Second, on Smith’s view (one version, perhaps, of) lunacy just is having mental anticipations that are systematically out of kilter with the order in which objects appear. That is, when our firmest, most habitual, natural relations of causation closely track our natural or common environment this is constitutive of (mental) sanity and rationality (recall this post for more evidence and context). In fact, in Smith’s treatment of the impact of custom and education among so-called civilized societies (that is, in law-governed places), he describes immoral behavior with the same language as the thought experiment we’re discussing: one is “transported to do any thing contrary to justice or humanity.” (The Theory of Moral Sentiment 5.2.10, 207) It is as if Smith thinks of immoral behavior in terms of one’s being an alien in one’s own environment. [According to Smith one way in which our ordinary sanity can sometimes come undone and even cause permanent lunacy is through the workings of the so-called “strong” passions (Astronomy, 1.2).]
It may seem that my use of “rationality” here is unwarranted, especially if one’s emphasis is on Smith the purported ‘social scientist’ (e.g., Campbell 1971). Even so, in his treatment of anticipations, Smith brings together two kinds of expectations: the empirical and the normative in a manner akin to recent meta-ethics (see, for example, Michael Smith's The Moral Problem).* I take it as uncontroversial that when Smith speaks of the “person of soundest judgment” he just is describing the rational person.
According to Adam Smith an individual’s (a groups, society’s, etc.) judgment is developed and calibrated in a particular environment. When Smith talks of an “irregularity,” this tends to be a regular deviation from the expectations of what is scientifically expected (see, especially, “Astronomy,” 4.45; 4.68-71, EPS, 100-1).
To return to Bell, then. He (echoing Della Rocca) turns the issue at hand toward Hume's rejection of the PSR. And, indeed, that is undoubtedly at stake in Hume's account. But as Smith passage intimates (and this gets further developed in the History of Astronomy), Hume is also pointing toward a related, but distinct issue: scientific thought is often taken to be co-extensive with the rational (i.e., Hume's "endowed with the strongest faculties of reason and reflection,"), then to oppose science (say because it relies on limited data) can be taken to be a sign of madness. Yet, for all of Hume's embrace of common sense, sometimes Hume likens his own philosophy famously (or infamously) to a delirium--as Plato and Deleuze teach us, philosophy must always flirt with madness. Perhaps, then, it is impossible to put a just value on a true metaphysics, after all.
*I thank Michael Gill for the reference.