Digressions&Impressions

Debating Kant & Spinoza with Boehm (II): on the First Antinomy, Spinoza & Newton

A central part of Omri Boehm's book, Kant's Critique of Spinoza (especially Chapters 2&3) is a re-reading of Kant's antinomies in order to show that these address Spinoza and Spinozism in order to help explain the Critical Kant's claim that  the two viable metaphysical options are either Kant's Transendental Idealism, which in Boehm's hands is itself a regulative Spinozism, or a Transcendental Realism, which can be best understood as a species of metaphysical Spinozism (recall this post; and also this post on the debate over the PSR between Garber and Della Rocca  as well Alex Douglas's post). I am fully persuaded by Boehm that Spinoza is, indeed, a central interlocutor (for the bad reason that it fits my views of the pre-Critical Kant).

Boehm notes correctly that Descartes and Leibniz, who distinguished between space as indeterminately large and as infinitely large in order to claim that space was indeterminately large (not infinite), reserved "true infinity to God." (75) By contrast, "Spinozism is committed to the world's infinity." (79) This suggests to Boehm (and I agree) that Kant is concerned with Spinozism in the first antinomy's anthithesis. But does it follow that Spinoza is the only such Spinozist known to Kant? I think not. For, Newton, too, is such a Spinozist not just in texts unknown to eighteenth century readers, but also in the General Scholium (and the Principia more generally). This is not obvious if one identifies, as too many Kant scholars stilll do, Clarke's correspondence with Leibniz as the Newtonian position. Even if there weren't Newtonian texts (known to Kant) that suggest otherwise, it would be a mistake to treat Clarke's presentation as echt-Newton because the whole exchange between Leibniz and Clarke is framed from the start by Leibniz's insinuation at the start of the exchange that Newton is a crypto-Spinozist (an explosive charge by the time Leibniz makes it).

For, Newton embraced the true infinity of space right at the start of the Principia: ‘‘Now no other places are immovable but those that, from infinity to infinity [ab infinito in infinitum], do all retain the same given position one to another, and upon this account must ever remain unmoved and do thereby constitute immovable space,’’ (Principia, scholium to the definitions). This is is a core Newtonian commitment unchanged through all the editions (see here for more details). In the General Scholium, added to the Principia's second edition, Newton explains the relationship between God and infinite space. I quote two passages: 

[A] [God] endures always and is present everywhere, and by existing always and everywhere he constitutes duration and space. Since each and every particle of space is always, and each and every indivisible moment of duration is everywhere, certainly the maker and lord of all things will not be never and nowhere (quoted from the Cohen/Whitman translation, p. 941).

[B] “the supreme God necessarily exists, and by the same necessity he is always and everywhere” (941; emphases added)

On [A] God and time (and space) co-exist eternally – so there is no first creation of a moment of time. While Newton denies that God should be identified with space (and time), "He is not eternity and infinity, but eternal and infinite; he is not duration and space, but he endures and is present," God is, thus, always and everywhere immanent within the order of nature (understood as existing in space and time). Newton does not shrink back from claiming that space and time are truly infinite. Moreover, space's existence is a (non-causal) consequence of God's existence ("by existing always and everywhere he constitutes duration and space"). In the General Scholium, Newton does not explain the nature of this consequence. (There is a rich scholarly literature on Newton's (ms) De Grav, where Newton both recognizes the infinite/indefinite distinction which he associates with Descartes's fears about being acccused of atheism, and offers an emanative account of the relationship between God and space; see here for my treatment and survey of literature.)

In the fourth letter to Bentley (which became public in the middle of the eighteenth century), Newton allows “there might be other systems of worlds before the present ones, and others before those, and so on to all past eternity, and by consequence that gravity may be coeternal to matter, and have the same effect from all eternity as at present” (in the Janiak translation, 102). The pre-Critical Kant also embraced the position that ‘‘infinite space teems with cosmic systems’’ [der unendliche Weltraum von Weltgebäuden wimmele] (UNH, Part 1, chapter 1 257 (247)). In context, Kant refers to Huygens (who is, in part, responding to Newton) as his source.

On [B] the modal status of God’s existence and God’s infinite spatiality is said to be identical. So if God is, infinite space (and time) is. Newton does not explain his views on necessity in the General Scholium (or elsewhere, I think), but I pointed out last week that now-less-familiar works by Clarke do so in terms of the final halting point of the PSR. Either way, Newton's views on God, space, and time are Spinozist. (Obviously in this post I have not said anything to motivate the thought that Newton is a monist about substance; but see here.) 

Of course, Newton's views are not identical to Spinoza because Newton treats space and time relatively symmetrically whereas in Spinoza space is and time is not an attribute of substance. In fact, it is worth noting that Kant (in a passage frequently quoted by Boehm) treats Spinozism as the view, "in which space and time are essential determinations of the original being itself." (Critique of Practical Reason) As such this characterization is closer to the historical Newton than to the historical Spinoza. (Boehm recognizes, of course, that Kant treats space and time more symmetrically than Spinoza does.)

So, returning to Boehm, he is simply wrong when he identifies Newton with the view "that the world is not infinite and has a beginning" (80) and that there is "only one relevant rationalist thinker who has a good reason to insist, as does the Antithesis [of the first Antinomy], that world is positively infinite," that is Spinoza. (80) (To avoid confusion, Boehm treats Newton as a rationalist dogmatist.)

Intriguingly, while Boehm has to explain why, given his identification of the position in the Antithesis with Spinoza's, Kant would attribute the position to "a principle of pure empiricism," my suggestion that it could just as well be Newton's faces no such quandary. (That is everything that Boehm claims about what Kant might mean with 'pure empiricism' here could also be attributed to Newton.) Moreover, when Kant [A471] identifies the Antithesis's empiricism (that goes too far) with Epicureanism (as Boehm notes on p. 105 in footnote 28), this fits, as I have argued elsewhere, Kant's pre-Critical interpretation of Newton as a kind of Epicurean. (Why he would do so I have explained here.) 

So, what follows from this? Kant did, I think, distinguish Newton and Spinoza when it suited him. But in Kant's hands, Spinozism mixes elements from Newton's and Spinoza's writings. (This is not to deny that Spinoza is the more consistent Spinozist than Newton, of course.) This observation does not undermine Boehm's larger claims about the philosophical dialectic, but it does undermine his interpretation of Kant.

Debating Kant & Spinoza with Boehm (I)

Della Rocca’s only valid case in point is the question “in virtue of what is ‘causa sui’ conceived as existing?” and, to that question, he can answer (if he can) by denying the validity of the question: causa sui, he will say, “is conceived to exist because it is what it is.” Only in the latter case may the PSR’s “invirtue-of-what” question be a bad question, reducible to a genuine misunderstanding.
But, in this light, it turns out that rationalism ultimately assumes the validity of the traditional ontological argument. The question in virtue of what substance is conceived to exist can be dismissed as a mere misunderstanding of the concept only if existence is a predicate, participating in substance’s essence. What needs to be underlined is that at stake is not merely a rationalist argument concerning the theological question of God’s existence. At stake is the viability of the rationalist position itself: Without the ontological argument, the edifice of conceivability and of the PSR falls apart.--Boehm, Kant's Critique of Spinoza, (160)

First a paragraph of (contextual) stage-setting, then I get to philosophy. The main interpretive claim of Omri Boehm's Kant's Critique of Spinoza, which is full of wonderful arguments and insightful unterpretations, is: that (a) in his pre-critical period, Kant isn't just familiar with Spinoza, but that he is a Spinozist (especially in the Beweisgrund); (b) and that in Kant's critical period Spinoza (and the threat of Spinozism) isn't just a central  interlocuter (as a close analysis of the antinomies reveals), but that Kant is a regulative Spinozist. On (a) Boehm's argument nicely converges with my own claims about the pre-critical Kant (especially the Natural History of the Heavens). Our entirely independent arguments offer mutual support. (Isn't that peachy.) I just want to make two qualifications: (i) if Boehm had engaged more thoroughly with Ursula Goldenbaum's work (on Mendelssohn, and her work on historiography) he could have availed himself to more evidence and usefully complicated his story; (ii) Boehm has a tendency to treat the pre-critical  Kant as a stable position rather as, itself, working through, and debating with, many interlocutors (I recommend this piece by Massimi for some of Kant's range). On (b) I leave it to Kant specialists to debate Boehm, although it is worth noting that Boehm's argument also allows -- with self-conscious nods to Jonathan Israel's work [but for reservations see here]-- us to put Kant into a wider eighteenth century context (still surprisingly rare in Kant scholarship).

The philosophical excitement of Boehm's book is to be found -- by way of treating Kant as critically engaging with Spinoza -- in the ways the ontological argument and the Principle of Sufficient Reason (PSR) mutually illuminate each other and, each in turn, debates over, modality, Causa Sui and, ultimately, the status of fatalism and (ahhh) nihilism. This is not just a matter of historical curiosity. Now that species of dogmatic (the technical term is 'knee jerk') metaphysics are back in fashion, including robust defenses of monism and the PSR, the question of nihilism and fatalism may well return as well (at some point). My plan is to engage with some of these rich issues in the course of a number of posts (and itself part of the series on the PSR that I started in context of Garber/Della Rocca debate).

Today, I focus on the “in virtue of what is ‘causa sui’ conceived as existing?” question (see the quote at the top of the post). This matters for the larger debate because if there is a decent Spinozistic answer to that question than transcendental realism is still in the game. My unargued for assumption here is that because Boehm accepts Della Rocca's conceivability focused interpretation of the PSR (seeLærke for reservations), he (Boehm) misses alternative ways to explore the issue.

I start with a low-level move. Boehm writes:

In Kant, naturalistic causality is understood as mechanical, or efficient causality. We naturalistically understand an event if and only if we see how it necessarily follows from another event that precedes it. Arguably, Spinoza favors a similar conception. A thing, A, is said to be the cause of another, B, if B necessarily follows from A (e.g., E Ip16c1; Ip25; II p5). Of course, a mechanistic conception is the hallmark of seventeenth-century scientific naturalism, of which Spinoza is supposed to be a champion. Now if one clings to this efficient naturalistic conception, the notion of a “self-caused entity” is identical to a notion of an entity that is “not caused at all.” For the causal conception that’s assumed in the notion of a self caused entity is entirely different from—in fact, it excludes—the naturalistic-efficient conception. 

I doubt Boehm gets Kant's account of causation right in the first sentence (without, at least, mentioning the role of laws). But let's stipulate he does--he is certainly expressing a Kantian prejudice. (It is odd that after claiming that "the human intellect genuinely grasps how one thing can cause another," (143) there is no mention of Locke and Hume, who undermine the intelligibility and appeal of precisely this mechanical conception.) But in Spinoza (and arguably in Locke) the model form of causation  is the way in which a (hidden) essence produces regular or (all things being equal) exception-less, (visible) effects. That is, in fact, the natural reading, too, of E1p16C1 (and E1p25 & E2p5, although the latter proposition is not explicit either way).* I often warn folk not to read Spinoza as a fellow traveler of the mechanical philosophy or even the scientific revolution (see here). This is not to deny that Spinoza also recognizes the mode-on-mode (billiard-ball) model of efficient causation (E1p28), but it is derivative from the exemplary model (and also has lower epistemic status).

Boehm might respond, gracefully, fair enough, Schliesser, but so much the worse for Spinoza; 'esssence --> effect' is a remnant of a discarded Aristotelian science. But that would be too hasty here. For, first, Spinoza does not rely on final causes/teleology (in this context). Second, Spinoza's 'essence --> effect' is, in part, modeled on (as he himself says in the Appendix 1 to Ethics 1) a formal cause explanation once common in geometry. And we can understand causa sui in such terms. (See this seminal article by Huebner; and anticipations in Viljanen and Schliesser.) Moreover, the way  we understand such a hidden essence can be made compatible with both (the role of laws) in early modern science (and, in the hands of Joe LaPorte, modern science). [There is also historical irony that Boehm's Kantian rejection of causa sui echoes the Scholastic rejection of causa sui when they encountered it in Descartes (and Spinoza).]

Even so, it looks like Boehm still may say that even if the causa sui** can be made respectable, we still have to make existence a first order predicate to make the position cogent. Let's accept that (it is, after all, the natural reading of E1D1). Some other time I'll explore if it follows that in Spinoza we should treat existence as an attribute (as I used to think), or, (as I now think) that (no less dazzlingly) existence just is truth (recall this post). Rather, here I want to close with a Spinozistic, alternative (due to Clarke! [recall]) answer to the “in virtue of what is ‘causa sui’ conceived as existing?” question. For, from the vantage point of the (Spinozistic) PSR, the only proper answer is 'necessity.' Necessity both legitimately ends an explanatory regress and is a proper primitive ground that avoids opening the door-too-easily-to-idealism (as Della Rocca's version of the PSR does) and building a kind of harmony-between-mind-and-world-view (the optimistic side of rationalism) into Spinozism from the start. For, once one shows that something  is necessary, there is no need for a further question (obviously, this can be easily abused in human affairs as a species of ideology, so one should be suspicious of instances of this strategy).

On Saving the Hebrew Bible from Analytical Theology

Swinburne’s account of revelation reflects a common view of what is taking place when an Israelite prophet tells us he is speaking words that have been taught to him by God. But...this view is mistaken as an interpretation of what is meant by God’s speech in Hebrew Scripture.[15] One obvious indication that there is something wrong with this interpretation is the fact that the biblical prophets explicitly reject the second plank of Swinburne’s account, namely, the supposition that the prophet’s words have to be taken on authority or faith because their truth cannot be tested by those that hear it. Indeed, Moses himself is presented as rejecting Swinburne’s position in what is perhaps the most significant passage concerning the nature of prophecy in all of Scripture, the law of the prophet in Deuteronomy:

I will raise them up a prophet from among their brethren… and put my words in his mouth…. And if you say in your mind, “How will we know the word that the Lord has not spoken?” Know that if a prophet speaks in the name of the Lord, and the thing is not, nor does it come, that is a thing that the Lord has not spoken, but the prophet has spoken it out of presumption, so do not fear what is from him.[16]

In this passage, Moses hands down God’s law respecting the recognition of prophets by the broader public. Earlier, Moses has already rejected appeals to signs or miracles as being a legitimate means of authenticating the prophet’s message.[17] Here he tells the people that if they wish to distinguish God’s word from what has been spoken presumptuously, the test is whether the things that are spoken really come to pass: If “the thing is not, nor does it come,” then anyone can know that what has been said in God’s name “is a thing that the Lord has not spoken.” ...Moreover, there are numerous additional passages that suggest that the wisdom in God’s teaching can in principle be recognized by anyone, from any nation;[19] and that the people of Jerusalem would be able to distinguish right teaching from wrong if only they would make a careful comparison using their own senses and judgment.[20] Together, these passages suggest that in Hebrew Scripture—or at the very least, in some of its most prominent texts—God’s word is not at all something that must be accepted on faith due to the credibility or authority of the prophet. On the contrary, the prophet bearing a teaching that is truly God’s word is supposed to be recognizable by anyone, using conventional human experience as the basis for judgment.[21]

If this is right, then a reasonable account of God’s word as it appears in Hebrew Scripture will not be able to include Swinburne’s third plank either, which calls for a sharp distinction between knowledge that has been “revealed,” and the products of philosophy and science that are derived from conventional human experience. As the empiricism of the Mosaic test of the prophet’s message suggests, Israelite prophecy was a forerunner and family relation of what later generations knew as philosophy and science.--Yoram Hazony, Jerusalem Letters: What is Revelation?

In context, Hazony is criticizing an important distinction (reason vs revelation) that he takes to be underwriting a key hermeneutic move common in (Protestant) analytical theology/metaphysics:  that the authority of Biblical prophets ultimately rests on faith. While this is an important issue, it is part of a larger project (with which I have considerably affinity) in which Hazony defends the integrity of what he calls the Hebrew Bible from Christian reinterpretation (one of his targets his Plantinga) in which some of the Biblical prophets have as much claim to wisdom as Greek philosophers. (A key part of this move is that history and social analysis are integral to philosophy.) One consequence of Hazony's move is that a central part of the Hebrew Bible becomes continuous with what later became known as "philosophy and science." I call this Hazony's continuity thesis.

Hazony's continuity thesis position was not un-common among a strain of seventeenth and eighteenth century English, protestant natural philosophers with a fondness for King Salomon, Jeremiah, and Ecclesiasticus, especially. This strain includes Bacon (recall), Clarke (recall), and -- the biggest prize of all, Newton (e.g., the General Scholium).* This is useful to keep in mind because it allows us to recognize that Hazony's continuity thesis is also available to non-Jewish readers of the Hebrew Bible. It also raises the very important historical-conceptual question of why the continuity thesis fell out of fashion among the Protestant learned. (This presumably has something do with theological responses to the Enlightenment thought of Hume and Kant.) 

Here I raise a problem for Hazony's position. For, with his appeal to Deuteronomy 18:18, he has left the reader without enough resources to distinguish between true and false prophets. (Hazony accepts the distinction because he treats Parmenides as a false prophet, although "not entirely false.") A true prophet speaks "truly God’s word." Let's grant, for the sake of argument, that "whether the things that are spoken [prophesied] really come to pass," that is, predictive accuracy, is a necessary condition for true prophecy. It is not sufficient. Because as the Hebrew Bible recognizes false prophets are also capable of accurate prediction--Balaam is the exemplar in this category.** To put the point anachronistically, not all predictively accurate science is moral science.

This is why in addition to predictive accuracy the Hebrew Bible also adds a content restriction on true prophecy. So, for example, at Deuteronomy 13:2-3, in the midst of discussion of prophecy, the Bible remarks that if a predictively accurate prophet also adds "Let us go after other gods, which thou hast not known, and let us serve them; [then] thou shalt not hearken unto the words of that prophet, or that dreamer of dreams." So, Hazony needs to explain the evidential basis for the authority of such content restriction(s). If Hazony wishes to deny faith and revelation a role here, he is presumably left with either an appeal to tradition or an appeal to the principle of sufficient reason. The former is not shared by everyone, while the latter goes against his empiricist sensibilities; presumably I have overlooked some options, but I would welcome learning which ones.

On Necessity in Clarke & Newton (and Spinoza), against Toland....

In his correspondence with (a then very youthful) Joseph Butler, Samuel Clarke writes the following:

Necessity absolute and antecedent in the order of nature to the existence of any subject has nothing to limit it; but if it operates at all (as must needs do), it must operate (if I may so speak) everywhere and at all times alike…. (Clarke’s “Answer to Butler’s Third Letter,” Dec 10, 1713)[1]

To put Clarke’s point informally: absolute necessity has the same impact everywhere and all times and should have the same consequence everywhere and all the time. So, if such necessity operates in some respect, Y, then we ought to expect Y to be homogenous in relevant ways. And if the most fundamental form of necessity operates in all (possible) respects, then we ought to expect general homogeneity.   

This view of necessity turns out to be a non-trivial principle that, surprisingly enough, is shared by Clarke and Spinoza, and, even in considerable part, by Newton. (Recall Newton's claim in the General Scholium (added to the third edition): “No variation of things arises from blind metaphysical necessity, which must be the same always and everywhere.”) I emphasize two features of Clarke’s position. First, according to Clarke necessity is the “formal cause” of God (Clarke’s “answer to sixth Letter to another Gentleman” [published first in 1738]).[2] That is to say, Clarke does not just allow the question, ‘what causes God?’ to be intelligible,[3] but it even has a proper response: in a certain sense, one can say that for Clarke God is the consequence of a species of necessity.[4]  There is, in fact, an unmistakable echo of this doctrine of the relationship between necessity and God in Newton's "General Scholium:" “’Tis allowed by all that the supreme God exists necessarily; and by the same necessity he exists [391] always and every where” (emphasis added). In the quote, Newton insists (i) that God’s necessary existence is common ground among all philosophers.[5] Newton, then, (ii) ascribes to necessity explanatory ‘power’ to help account for (at least some of) God’s properties. It’s this type of explanatory power that is captured by Clarke’s claim that necessity is a formal cause.

Second, Clarke uses the necessity as formal cause of God principle to rule out the existence of multiple substances (Clarke’s first response to Butler, 10 nov 1713, and see Clarke's A Demonstration of the Being and Attributes of God, [hereafter Demonstration] VII). So, like Spinoza [(E1D1 & E1p7)] & (E1p5&E1p7), Clarke treats God as the only true substance.[6] In particular, in order to make credible substance monism, Clarke relies on the idea that absolute necessity does not just have the same impact everywhere and all times and should have the same consequence everywhere and all the time, but also that in the most absolute sense these consequences ‘displace’ the ‘instantiation’ of other hypothetical (but not genuinely possible) effects derived from hypothetical (but not genuinely possible) causes. [7]

If we attend to some of the further details of Clarke’s letter to Butler, we also learn something about the explicit target of Clarke’s argument:

A note on the Dauler Wilson Garber debate over Berkeley’s Corpuscular Scepticism

[I]t will be demanded to what purpose serves that curious organization of plants, and the animal mechanism in the parts of animals; might not vegetables grow, and shoot forth leaves of blossoms, and animals perform all their motions as well without as with all that variety of internal parts so elegantly contrived and put together; which, being ideas, have nothing powerful or operative in them, nor have any necessary connexion with the effects ascribed to them? If it be a Spirit that immediately produces every effect by a fiat or act of his will, we must think all that is fine and artificial in the works, whether of man or nature, to be made in vain. By this doctrine, though an artist hath made the spring and wheels, and every movement of a watch, and adjusted them in such a manner as he knew would produce the motions he designed, yet he must think all this done to no purpose, and that it is an Intelligence which directs the index, and points to the hour of the day. If so, why may not the Intelligence do it, without his being at the pains of making the movements and putting them together? Why does not an empty case serve as well as another? And how comes it to pass that whenever there is any fault in the going of a watch, there is some corresponding disorder to be found in the movements, which being mended by a skillful hand all is right again? The like may be said of all the clockwork of nature, great part whereof is so wonderfully fine and subtle as scarce to be discerned by the best microscope. In short, it will be asked, how, upon our principles, any tolerable account can be given, or any final cause assigned of an innumerable multitude of bodies and machines, framed with the most exquisite art, which in the common philosophy have very apposite uses assigned them, and serve to explain abundance of phenomena? Berkeley--A Treatise Concerning the Principles of Human Knowledge, Book 1, 60

[T]hat what has been objected in sect. 60 amounts in reality to no more than this:- ideas are not anyhow and at random produced, there being a certain order and connexion between them, like to that of cause and effect; there are also several combinations of them made in a very regular and artificial manner, which seem like so many instruments in the hand of nature that, being hid as it were behind the scenes, have a secret operation in producing those appearances which are seen on the theatre of the world, being themselves discernible only to the curious eye of the philosopher. But, since one idea cannot be the cause of another, to what purpose is that connexion? And, since those instruments, being barely inefficacious perceptions in the mind, are not subservient to the production of natural effects, it is demanded why they are made; or, in other words, what reason can be assigned why God should make us, upon a close inspection into His works, behold so great variety of ideas so artfully laid together, and so much according to rule; it not being credible that He would be at the expense (if one may so speak) of all that art and regularity to no purpose. Berkeley--A Treatise Concerning the Principles of Human Knowledge, Book 1, 64

There is a famous and thus far inconclusive, multi-layered debate between the two giants of early modern scholarship, Margaret Dauler Wilson (her paper) and Daniel Garber (his paper). The debate centers on Berkeley’s views on (what has been dubbed) ‘corpuscular skepticism,’ roughly, the idea that in addition to veil-of-ideas skepticism, Berkeley inherits from Locke skepticism about our ability to access to the posited to exist (real) corpuscular essences of things. One of the hermeneutic questions about Berkeley (and one that he faces with admirably forthrightness in Principles, Book 1, 60-66) is what right Berkeley has to posit such material corpuscles in his system. It is worth noting that the debate matters for the history of science (and philosophy) because in these passages, Berkeley helps promote a decisive shift in explanatory standards from an emphasis on essences to an emphasis on laws in the natural sciences. When we do not reflect on this, we tend to assume that such shift was a natural one, and perhaps already completed due to the influence of Descartes and the success of Newton’s Principia. But the shift in explanatory standards was, in fact, an eighteenth century achievement (unsettled again Lavoisier provided access to chemical essence). [See work by McMullin, Ducheyne, Downing, and your reporter.] 

But the Garber-Wilson debate and its reception has overlooked, I think, that in Principles 60-66, Berkeley is responding to an ingenious argument developed by Clarke in his (1704) Demonstration on the Attributes of the Being of God. It would be correct to label Clarke’s argument a ‘design’ one, but in doing so we also obscure the significance of Clarke’s argument. For the particular design argument that Berkeley is responding to is an argument relies on the history of empirical success of science. In particular, in Principles 60 and its restatement in 64, Berkeley is responding to a hypothetical critic that has assimilated Clarke’s particular argument (the “common philosophy”) in defense of the existence of not just general, providential “final causes,” but local design (or finality). Clarke’s argument relies on then recent and progressive, specialized (to use some anachronism) scientific knowledge. Clarke writes: