9. To choose those constructions which without straining reduce things to the greatest simplicity. The reason of this is manifest by the precedent Rule. Truth is ever to be found in simplicity, & not in the multiplicity & confusion of things. As the world, which to the naked eye exhibits the greatest variety of objects, appears very simple in its internall constitution when surveyed by a philosophic understanding, & so much the simpler by how much the better it is understood, so it is in these visions. It is the perfection of God's works that they are all done with the greatest simplicity. He is the God of order & not of confusion. And therefore as they that would understand the frame of the world must indeavour to reduce their knowledg to all possible simplicity, so it must be in seeking to understand these visions. And they that shall do otherwise do not onely make sure never to understand them, but derogate from the perfection of the prophesy; & make it suspicious also that their designe is not to understand it but to shuffle it of & confound the understandings of men by making it intricate & confused.--Isaac Newton ca 1670s-1680s, Rules for methodising | construing the Apocalyps. in Untitled Treatise on Revelation (section 1.1) [HT Eliot Sober]
Laurie Paul called my attention to Sober's essay on simplicity, which discusses, in passing, the passage quoted from Newton's papers. In the passage, Newton draws a distinction between confusing appearances (which exhibit "multiplicity") and an orderly and simple hidden (internal) constitution. I note here that his language is rather Rationalist (a "philosophic understanding" grasps the hidden constitution of things), but in context it's clear that the interpretation of Scriptures (or prophetic visions) and of nature (they are treated as analogous enterprises) is also an empirical matter (note the role of "observation").*
Sober does not mention the role of order, which in Newton is resolutely coupled with simplicity. Before I get to that it's worth noting explicitly, Newton's doctrine of simplicity here. Even so there is a subtle distinction between order and simplicity. Let me first explain simplicity. For, note the difference between (i) simplicity being a feature of God's works, especially the internal constitution of things and (i*) simplicity being a cognitive feature accompanying a philosophical understanding of that internal constitution of things. Truth just is when (i) and (i*) match. It also turns out that the simplicity in (i*) also involves (i**) a property or virtue of a successful epistemic reduction to a more limited number of elements. Newton is here echoing Boyle (as Yoram Hazony has argued in a different context). To be sure, a 'construction' is what we would call an 'intepretation,' but for reasons that will become clear below, I am going to be happy to trade on an equivocation in which 'construction' also evokes a concrete model.
Order, however, is a feature (I am inclined to say, a perfection) of God: "He is the God of order"--this evokes 1 Corinthians 14:33-40. (There order seems to really mean 'peaceful,' especially of prayer-service & preaching -- sadly, in context women are treated as a source of disorder.) A natural reading is that God's order explains the absence of confusion (that is, order) in the hidden constitution of nature.
That God is the God of order is a feature, not a bug, of a very important argument that I have dubbed (recall, here too, and here) the 'transcendental version of the Posidonian argument' that can be traced back to Cicero's On the Nature of the Gods. (Some version of it is clearly articulated in Boyle and Clarke.) It can be rendered as follows:
(I) A condition of the possibility of (an intended) successful scientific representation or concrete model of (a region of) nature is that (a region of) nature is orderly
(II) Nature's hidden order could not be the product of chance [as suggested by Epicureanism] or necessity [as suggested by Spinozism], but only by God
(IV) ∴ There is a God (of order)
I have worded [II] in such a way as to allow that God may just emanate his order to Nature. I have worded [I] to allow concrete models -- e.g., a portable planetarium -- to play a key role in the argument (as they do in Cicero, Boyle, and Clarke). In addition, I'll stipulate that one way to cash out a successful scientific representation or concrete model of the hidden structure of nature, is in terms of simplicity, epistemic reduction, and representational accuracy. Obviously, the first two premises may well be thought controversial (and here I am ignoring different kinds of interpretations we may put on these premises). Some other time I'll explore how reasonable they would have been in the early modern period (and how they can be seen to presuppose a commitment to PSR).
This argument violates what we may call a 'neutrality requirement.' The thought behind the neutrality requirement is that when science plays a rule in establishing facts/features/stuff/phenomena (etc.)about the world -- like its hidden structure or order --, it ought to be neutral with regard to these facts (features, etc.). The neutrality requirement, we may say a lack of bias, underwrites the epistemic authority of science in the context of controversy. The transcendental version of the Posidonian argument violates the neutrality requirement when it comes to order; it presupposes it.
As the eminent Spinoza and Kant scholar, Ursula Renz (who likes transcendental arguments), noted in recent discussion of some of this material, violating neutrality requirements just is what transcendental arguments do. (This is just another way of explaining the way in which transcendental arguments tend to feel circular.) This is worth emphasizing because we live in a philosophical culture that is attracted to at least one rather influential transcendental argument (the so-called Quine-Putnam indispensability argument which appeals to the authority of science to argue for the existence of [or ontological commitment to] mathematical objects which are indispensable for science functioning).**
Here I do not wish to prove that Newton was explicitly familiar with the Posidonian argument (that's for another time, although if Dennett is right about Descartes then there is a direct source, but Boyle is also a possible source; later he can learn about itfrom Locke and Clarke). But it is worth noting here that he explicitly accepts its conclusion, tacitly assumes the truth of (II), and can be charitably read to be committed to (I). Every scientific success he generates, firms up his commitment to its conclusion, and, in turn, spurs on his science.