Alien Structure and Themes From Analytic Philosophy Matti Eklund Uppsala University matti.eklund@filosofi.uu.se [forthcoming in Giornale di Metafisica] 1. Introduction: orthodoxy We think of the world as consisting of objects, with properties and standing in relations. There are, to be sure, different views on what objects etc. there are, and on what their natures are. And some theorists want to subtract some elements from this picture. For example, the ontological nihilist says that there are no objects. But still, the view described is very much orthodoxy-so much orthodoxy that one may need to be reminded that the view that the world consists of objects, with properties and standing in relations is, precisely, a view. Alongside the metaphysical view outlined, there is a related view regarding the representation of the world. According to this view, the world is perspicuously represented using only familiar linguistic means-singular terms, predicates, firstand possibly higher-order quantifiers, etc. There are significantly different views regarding how language works exactly, as well as significantly different views on how singular terms work, how predicates work, etc. Still, this view on the representation of the world is also very much orthodoxy-and so much orthodoxy that one may need to be reminded that it is a view. I will here discuss whether these orthodox views can reasonably be rejected. Specifically, I will ask whether there might there be categories that should be added to this standard picture. Might there be alien entities that don't fit into the usual categories? As I will put it: Might reality have alien structure? As already mentioned, some theorists defend the view that there are no objects. This is a radical view, but in the first instance it only subtracts something form the orthodox view. It is also common, of course, to not countenance such entities as properties and relations. But also a nominalist who rejects the existence of such things can well believe the world to be property-ish and relation-ish, e.g. in that the most perspicuous representation of the world contains oneand many-place predicates. I will for ease of exposition continue to describe the orthodox view as involving belief in objects, properties and relations. To get the reader into the spirit of the investigation, a little thought experiment might be useful. Suppose an explorer of a faraway planet returns and tells us this of the community there and the place they inhabit. The environment, she says, is not very different from well-known places on Earth. The people there are as practically successful in navigating their environment as we are in navigating ours, and they have successful science, as shown for example by their technological advances. But the language they use, both in daily life and when engaging in scientific inquiry, is radically different from ours – so different that their words can't be classified as belonging to any of our linguistic categories. We face here an especially radical form of nontranslatability: not simply a language with singular terms and predicates we cannot translate into our language but a language whose words belong to altogether different categories. By immersing herself in this community the explorer managed to learn their language; and the explorer also managed to teach some of them our language. She reports that while her informants did learn our language, in the sense that they learned which sentences it is appropriate to utter when, they did express incredulity regarding the idea that our language could really express truths, for they found it incredible that reality could contain the sorts of entities required for sentences to be true, entities like objects, properties and relations. Can this explorer be believed? There are some different questions here. One is whether what the explorer describes is as much as a coherent possibility. Below I will focus on doubts that may be 2 raised. Another is whether, even if this is a coherent possibility, it really is plausible that a familiar kind of external world could be successfully theorized about using alien resources: maybe alien resources could only be used to successfully theorize about a different kind of world. Assuming the explorer can be believed, other questions arise. The explorer reports that the members of this community don't think our sentences express truths. How are we to react to this stance of theirs? There are some different possibilities to distinguish between here. One is that at most the sentences of one kind of language are capable of expressing truths, whether it is the sentences of our language of theirs. Another is that the differences between the languages are notational only, in such a way that the same features or aspects of reality make true sentences of both languages: the differences between the language do not correspond to possible metaphysical differences. A third possibility is that reality is rich, in the sense that it contains both kinds of structure: there are the objects, properties and relations needed to make our sentences true, and the Xs, Ys and Zs, whatever they are, needed to make their sentences true. Distinguishing between these possibilities is just to scratch the surface. There are many different questions that can be raised, and many live possibilities. Let me for now just introduce one more distinction. In recent metaphysics, it has become common to distinguish questions about what the world is like from questions about what the world is fundamentally like.1 To take a trite example, even if it is true that there are tables and chairs, it may be that tables and chairs are not among what fundamentally exists, which may be (say) fundamental physical entities and sets thereof. Given this distinction, one issue regarding familiar vs. alien languages is whether sentences of both languages express truths; and another is whether sentences of both languages express fundamental truths. Maybe our language is good enough for expressing some truths, but inadequate for expressing the alien structure of fundamental reality. 2. Unclarity So far, so abstract. I trust that the issues brought up seem interesting. But how can we put more flesh on these bones? What does "alien" mean here? What does it even mean to say that something isn't an object, property, etc.? (And might the "etc." hide difficulties?) What does it even mean to say that a language does not involve reference, quantification over objects, predication, etc.? (And again, what about that "etc."?) There are different sorts of skeptical reactions one might have. One is the reaction that an alien structure hypothesis is not worth bothering about since the familiar categories are so general that no sense can be made of the idea of things falling outside these categories. Give me whatever entity you like, the reaction is, and that entity will be guaranteed to belong in one of the familiar categories. Another skeptical reaction is that the "familiar categories" are so loosely understood that the question of whether reality contains alien structure is not precise enough to be investigated problem. The best way to counter either kind of skepticism is to show how it can be reasonably discussed whether there can be alien structure. Below I take some first steps. But needless to say, there will be much more to say about this than I can reasonably try to say here. (A completely different kind of skepticism about the present project is that there already is some extant theorizing which provides examples of purported alien structure-in fundamental physics, in the history of philosophy, or in non-Western philosophy. Such skepticism too is worth discussing, but will have to be discussed elsewhere.) 3. The somewhat alien Here is one way to turn the whole rhetoric of familiar vs. alien structure into something more tractable: a recipe for generating somewhat alien hypotheses. In the literature, there are different theories of what objects, properties, etc. are. There are also different theories of how language works, including 1 For an overview see T. Tahko, Fundamentality, in E. Zalta (ed.), Stanford Encyclopedia of Philosophy, https://plato.stanford.edu/entries/fundamentality/. 3 what characterizes singular terms, predicates, etc. Now take any false such theory. Even if the theory in question is false-what it says about "objects" isn't true of objects, or what it says about "predicates" isn't true of predicates, etc.-the theory can be true of something else. A theory falsely describing how some things work can be true of some other things. Even if my theory of, say, predicates is false, in the sense that it doesn't accurately describe how our predicates work, it can accurately describe some linguistic devices. Even without going into details, these devices will be somewhat alien. By what has been said, they in some way function differently from how our predicates work. But they can be expected to be only somewhat alien, for the theory that describes them was originally designed to describe actual language. This is still abstract. (I did say that what I was going to present was a recipe.) But consider a familiar, widely rejected theory of predication, that of Gottlob Frege.2 On Frege's view, predicates refer to a special kind of entity, what Frege call "concepts", and this is what distinguishes them as predicates. It follows that one cannot use a singular term to refer to a Fregean concept. Even if Frege's view should be rejected, might not the predicate-counterparts of some other language work like Frege says predicates do? I am using Frege's view as an example because it is familiar. It is not entirely unproblematic to use it as an example. A main reason for rejecting Frege's view stems from the so-called "concept horse" problem. The problem has several aspects but one aspect is that it seems that we clearly can refer to the referents of predicates using singular terms: for example, we can refer to the referent of "horse" using "the concept horse", or, for that matter, "the referent of "horse"". This problem can be argued to generalize beyond our language and to other possible languages. If Frege had claimed not that our predicates refer to entities which cannot be referred to by singular terms but that some expressions of kind K of some other kind language do so, the same argument applies. If e is an expression of kind K, we can use "the referent of e". Another aspect of the concept horse problem is that Frege's view appears unstatable. By Frege's own lights one cannot really say that which one attempts to get at when saying "no concept is an object". This again applies even if the concepts only are the referents of expressions of some possible language. (But maybe, just maybe, it can be more palatable to hold that we have no way of expressing the semantics of some alien language, or no way of saying how the worldly correlates of our expressions relate to the worldly correlates of their expressions, than it is to hold that this is so regarding some parts of our own language.) 4. Objects As already discussed, one skeptical concern regarding whether reality might have alien structure has to do with whether we really can make sense of entities that are neither objects, properties or relations. To evaluate this kind of skepticism one must turn to how to understand the notions of object, property and relation. In a classic discussion, Bertrand Russell suggest three characterizations of the particular/universal distinction: in terms of subject/predicate structure, existence in space and time, and multiple-location.3 Start with the latter two characterizations. These are, respectively, to the effect that objects are in space and time but properties are nowhere (and nowhen), and to the effect that while objects can be wholly located at only one region, properties can be wholly located at several disjoint regions. What might a non-object non-property be here? As formulated, the suggestions leave open some possibilities: that such an entity is located in space or time (but not both), and that such entities cannot 2 G. Frege, Über Begriff und Gegenstand, in «Vierteljahresschrift für Wissenschaftliche Philosophie» 16 (1992), pp. 192-205. English translation On Concept and Object, in M. Beaney (ed.), The Frege Reader, Blackwell, Oxford 1997, pp. 181-93. 3 B. Russell, On the Relations of Universals and Particulars, in «Proceedings of the Aristotelian Society» 12 (1911), pp. 1–24. 4 be located anywhere. But both suggestions appear to overlook the possibility of abstract objects, and therefore to be problematic. The third characterization that Russell offers is that objects can be referred to only by singular terms, whereas properties can be referred to both by singular terms and by predicates. This is both better in itself, and yields some interesting alien possibilities. One is that there are entities that just cannot be referred to by singular terms. (Recall here that already Frege's concepts are like that!) Another is that there are alien entities, the flurgs, and an alien linguistic category, flebeleb, such that flurgs can be referred to by singular terms or flebelebs, while properties cannot be referred to by flebelebs. 5. Predication This is still rather abstract: what are these flebelebs and how are they supposed to differ from predicates? One way to make sense of flebelebs is to again appeal to the "recipe" from above, but can more be said? One useful resource for the project of considering alternatives to predication is the literature on nonlinguistic systems of representation, like maps. Michael Rescorla has recently argued that maps do not employ predication.4 The argument turns on how in maps, but not in language, the absence of a feature represents the presence of something. Lack of blue on the map indicates lack of water in reality. In her (2018), Elisabeth Camp puts the discussion in a more general theoretical setting.5 She groups predication with what she describes as similar operations such as functional application, appealed to in the theory of language proposed by Frege, Chomsky's operation Merge, and property instantiation.6 She then goes on to note supposedly significant similarities between these operations: among other things, they are digital (take a certain number of discrete elements as inputs), they are universal or nearly so (can combine a wide range of elements), and they are asymmetrical: "either just one element must be of a type that enables it to serve as input for the latter, or the operation itself creates an asymmetry among elements via the order of application". If this is on the right track, it is potentially helpful since it helps indicate what an alternative to predication would be like: it would be an operation which lacks one or more of these features. Now, it is hard to see how a linguistic representation could fail to be digital in the intended sense. Turning to the criterion of universality, differences in generality don't seem that deep. One can easily define linguistic devices that are like predicates, except that they do not satisfy the criterion of universality: but the differences between predicates and such devices would seem rather cheap. The asymmetry point seems more promising. What about an alternative to predication that is symmetry in that the inputs to the operation both play the same sort of role. While predicates are true of entities, what about, say, what we may call truth with, without this asymmetry? According to standard wisdom regarding familiar languages, singular terms and predicates have differents semantic role. The semantic role of a singular term is to refer. Predicates are more directly connected to truth: the predicate is true of what the singular terms refer to. But what if in a "true with"-language, the proper semantic clause for each simple expression which goes to make up an atomic sentence specifies what it is true with? All the simple expressions then have the same kind of role, and they all have the same connection to truth. Is it possible for there to be a language like the envisaged and would such a language really be a alien alternative to more familiar languages? This gets complicated. We can of course easily envisage a language such that the (atomic) sentences of that language will always be a collection of expressions belonging to the same category, and where there is a symmetry between the roles of the expressions. 4 M. Rescorla, Predication and Cartographic Representation, in «Synthese» 169 (2009), pp. 175–200. For criticism of Rescorla, see J. Kulvicki, Maps, Pictures, and Predication, in «Ergo» 2 (2015), pp. 149-173. 5 E. Camp, Why Maps are not Propositional, in A. Grzankowski and M. Montague (eds.), Non-Propositional Intentionality, Oxford University Press, Oxford 2018, p. 25. 6 See G. Frege, Ibidem, and N. Chomsky, The Minimalist Program, MIT Press, Cambridge, Massachusetts 1995. 5 But the question will be whether this really is an alternative to predication, in the relevant sense. Let me explain. We can imagine a language where each simple sentence consists of exactly two predicates, and the sentence "FG" of that language is true if equally many things fall under F as under G. But that doesn't seem to be an interestingly alien alternative to our language. Intuitively, predication is still an semantically important element of that language. In simple sentences, equinumerosity is predicated of the pair F and G. The mere fact that there is no separate expression expressing equinumerosity, but what the sentence "FG" says is a function of F and G being concatenated, does not rule this out. It may similarly be suggested that that when it comes to the semantic functioning of a sentence of the "true with" language, the proper understanding is that something-being true with-is predicated of the worldly correlates of the expressions which occur in the sentences. On the other hand, it can be maintained that whereas for us it may always be natural, when encountering a language in whose atomic sentences the components are always symmetrically related, to understand the atomic sentences of that language as being predications of symmetric relations, what exactly is there to say that this must be the best understanding of such a language? 6. Ramsey on the particular/universal distinction Thus far I have engaged in general discussion, seeking to show that the hypothesis that there is alien structure is significant and interesting. (Whether any such hypothesis is true is a different matter entirely, and nothing I have said bears directly on the issue of truth.) In the last three sections I will turn to something different. While the question of whether there may be alien structure relates to many issues in the literature on metaphysics and on philosophy of language and mind, I haven't yet related to these discussions. In the last few sections I will partly remedy this, by relating to a number of central discussions from the history of analytic philosophy. There are two general points to doing this. Looking at traditional debates in analytic philosophy through the lens of the question of the possibility of alien structure gives a new perspective on these debates. And by using these debates as input gives us more purchase on how to approach the issue of alien structure. I begin with Ramsey on universals. In a famous discussion, Frank Ramsey questioned whether one can make proper sense of the distinction between "particulars" and "universals"-roughly: objects and properties.7 The suggestion most extensively explored is that particulars and universals are distinguished by how they occur in propositions. This connects to the third proposal from Russell discussed above. Ramsey's discussion ends on a negative note. He concludes "Of all philosophers Wittgenstein alone has seen through this muddle and declared that about the forms of the atomic propositions we can know nothing whatever".8 On the route that Ramsey explores, belief in a particular/universal distinction is in effect tied up with believing that there is a kind of subject-predicate distinction in the propositions, or facts, which corresponds to the subject-predicate distinction in sentences. Using his example, "Socrates is wise", the believer in the particular/universal distinction holds that in the proposition expressed by this sentence, the constituent corresponding to "Socrates" plays the subject role, and the constituent corresponding to "is wise" plays the predicate role.9 The characterization is that objects can only play the subject role in propositions, whereas properties can play both the subject role and the predicate role. This should be reminiscent of Russell's proposed identification of objects as what can only be 7 F. Ramsey, Universals, in «Mind» 34 (1925), pp. 401-17. 8 Ibi, p. 417. 9 Ramsey is not completely consistent in his use of "proposition", but for the most part he speaks as if Socrates himself (as opposed to, say, the word "Socrates", or the sense of the word "Socrates") is a constituent of the proposition expressed by Socrates – and that is how I will speak here. There are of course different conceptions of propositions. Note that for many purposes, Ramsey could well have spoken of facts instead of propositions. 6 referred to by singular terms and properties as what can be referred to by both singular terms and predicates. A main argument Ramsey uses is that "Socrates is wise" and "wisdom is instantiated by Socrates" express the same proposition – but since these sentences with different structure express the same proposition we would be foolish to make assumptions about the proposition expressed. It may not be immediately accepted that the two sentences mentioned really do express the same proposition. Someone not believing that there is such a thing as wisdom for the term "wisdom" to refer to may hold that the first sentence is true and the second one false. And even someone who agrees that the sentences (necessarily) have the same truth-value can think that they still express different propositions, for example for the very reason that the propositions corresponding to the sentences would be structured differently. With regard to the latter issue, it is to be noted that, as Fraser MacBride (2005) has stressed, underlying Ramsey's thinking about these matters is a certain kind of Humeanism: an aversion to brute necessary connections.10 The necessary equivalence of the propositions expressed by our two sentences would be such a brute connection. I will not here evaluate Ramsey's arguments. Instead I will discuss the nature and extent of his skepticism regarding the particular/universal distinction and the forms of atomic propositions. Ramsey's arguments do not immediately call into question that there are such entities as Socrates or wisdom, or that these entities are constituents of propositions. The skepticism is much more targeted. One point Ramsey makes is there is nothing in the structure of propositions that determines that entities like Socrates play a certain kind of role in propositions while entities like wisdom play another kind of role. This point is by itself consistent with there being an important distinction between entities Socrates, Fido, this table, etc. – the entities we think of as particulars-and entities like wisdom, love, perfection, triangularity-the entities we think of as universals. Ramsey offers other arguments against thinking that there is such a distinction. And even if those arguments are persuasive, there is still no argument against reality being populated by the entities we tend to think of as particulars and universals; the arguments only tell against a certain way of thinking of those entities as divided up into distinct categories. One can easily envisage, at least in the abstract, a skepticism considerably more radical than Ramsey's. Might it not be that there is a language whose expressions are not classifiable as singular terms or predicates but whose expressions belong to semantic categories that are alien to us, and some sentences of such a language express propositions. Now consider the nature and structure of these would-be propositions. There are two different kinds of possibilities it is worthwhile to distinguish between. One is that these propositions are different in kind from the propositions expressed by sentences of languages more familiar to us: whereas our propositions contain as constituents things like Socrates and wisdom, the constituents of the propositions expressed by sentences of their language contain entities of alien categories. Another is that sentences of their language and sentences of our language can express the very same propositions, with the same constituents. In the latter case, there is obviously the question of what is the nature of these constituents. Do our sentences or theirs provide the most perspicuous representation of them? Maybe it is their sentences that provide the most perspicuous representation of the propositions expressed. In that case, the underlying nature of reality is importantly different from what we would have thought. 8. The syntactic priority thesis Bob Hale and Crispin Wright – the proponents of neo-Fregeanism – prominently affirm what is sometimes called the syntactic priority thesis: "objects, as distinct from entities of other types (properties, relations or, more generally, functions of different types and levels), just are what (actual 10 F. MacBride, Ramsey on Universals, in H. Lillehammer and D.H. Mellor (eds.), Ramsey's Legacy, Oxford University Press, Oxford 2005, pp. 83-104. 7 or possible) singular terms refer to".11 Neo-Fregeanism famously combines platonism and logicism, and Hale and Wright think that a syntactical analysis of the notion of a singular term is of crucial importance for this peculiar brand of platonism. The idea is that given the syntactic priority thesis one can establish platonism simply by showing that number terms are syntactically singular terms occurring in true sentences of the right kind. (I have urged elsewhere that it is an important problem that the syntactic priority thesis does not help with the question of whether the relevant sentences really are true, but never mind for present purposes. The syntactic priority thesis requires that it be possible to characterize singular terms simply by their inferential (or, it is sometimes put, "syntactic") properties – this because saying that singular terms are distinguished as such by having the semantic function of referring to objects introduces a problematic circularity. I might add that independently of the neo-Fregeans' aims, the syntactic priority thesis is of potential interest as far as the evaluation of alien structure hypotheses are concerned. If the notion of object is derivative upon that of a singular term in the way envisaged, then if one can show that there are alien linguistic categories that can be characterized by these inferential tests, then there are alien ontological categories derivative upon these alien linguistic categories. Given their aims, neo-Fregeans have embarked upon the project of actually formulating the inferential or syntactic tests by means of which to distinguish singular terms from other expressions. Proposed tests have met with significant criticism.12 But my aim here is not to evaluate the proposals but to assess the relationship between them and the questions raised here, in connection with the possibility of alien structure. Here is a proposed test due to Hale: Hale's Inferential Test A substantival expression α functions as a singular term in a sentence S1=<α,β1> [where β1 is the result deleting one occurrence of α from S1] iff H.1 for S1, the following inference is valid: from <α,β1> to Something is such that <it, β1>, H.2 for S1 and some sentence S2 = <α,β2>, the following inference is valid: from <α,β1> ∧ <α,β2> to Something is such that <it, β1> ∧ <it, β2>, H.3 for S1 and some sentence S2 = < α,β2>, the following inference is valid: from α is such that <it, β1> ∨ <it, β2> to <α,β1> or <α,β2>, where: Constraint 1.1 S2 neither strictly implies nor is strictly implied by S1, Constraint 1.2 the displayed occurrences of β1 and β2 in (H.2) and (H.3) are essential, Constraint 1.3 the displayed occurrence of α in S2 in (H.2) itself meets condition (H.3), Constraint 1.4 neither the conclusions of the inferences displayed in (H.1) nor the conclusions of the inferences in (H.2) are such that a point may be reached where a well-formed question for further specification may be rejected as not requiring an answer, Constraint 1.5 if valid, the validity of the inferences in (H.1)–(H.3) can be immediately recognised by any suitably competent speaker.13 This is just one of different proposed tests (and one that has been prominently criticized). But it is sufficiently representative that one can appeal to it for illustrative purposes. Hale's proposal is rather complex. A main point to make, relating to alien structure, is that even if Hale's test should turn out to be extensionally correct, surely there is no real reason to think that all languages – or even all expressively resourceful languages – will contain singular terms in exactly this 11 B. Hale and C. Wright, The Reason's Proper Study, Oxford University Press, Oxford 2001, p. 8. 12 R. Schwartzkoff, Singular Terms Revisited, in «Synthese» 193 (2016): 909-936 13 As stated by Schwartzkopff, cit., p. 913. The test is from B. Hale, Necessary Beings, Oxford University Press, Oxford 2013. 8 sense. It is trivial to come up with variants of Hale's criteria that will characterize a different category of expression: just consider an alternative where one or more of all these criteria is suitably tweaked. In an unpublished work, Richard Heck proposes that underlying the tests proposed by Hale and others (Heck centers his discussion on tests proposed by Dummett) is something rather more principled: what characterizes singular terms is scopelessness.14 (Some predicates too are scopeless. But Heck argues that considerations of scope anyway play a role also in distinguishing singular terms from predicates.) But even if this is indeed more principled, still the same question arises: why should all (expressively resourceful) languages contain scopeless expressions? Besides, even if singular terms can be distinguished from other familiar types of expressions by their scopelessness, there would remain the question of whether every scopeless expresson of every language would be a singular term. 9. The unity of the proposition The problem that has come to be known as the problem of the unity of the proposition is: by virtue of what is a proposition a representational whole, capable of truth and falsity? There are several versions of this problem that are discussed in the literature, with slightly different focus. Sometimes the focus is on sentences: what distinguishes a sentence, capable of truth and falsity, from other kinds of combinations of expressions? Sometimes the focus is on certain mental acts, judgments. Sometimes the focus is on facts, or states of affairs. And sometimes, as the most common name of the problem suggests, the focus is on propositions, the representational entities purportedly expressed by sentences. Theorists of otherwise different persuasions have prominently appealed to the notion of predication in their purported solutions to the unity problems. One clear example is Davidson (2005): ...if we do not understand predication, we do not understand how any sentence works, nor can we account for the structure of the simplest thought that is expressible in language. At one point there was much discussion of what was called "the unity of the proposition"; it is just this unity that a theory of predication must explain.15 Somewhat similar views have been expressed by Peter Hanks (2015): The source of truth conditions is to be found...in acts of predication through which, in the simplest cases, people attribute properties and relations to objects. The explanation for why propositions have truth conditions must appeal to these acts of predication.16 However, Hanks (like Scott Soames, who has expressed a similar view17), primarily focuses on acts, rather than on linguistic structure per se. What is striking about what these authors say is that they seem to make universal claims about predication. Davidson says that without a theory of predication we would not understand how any sentence works or understand the structure of the simplest thoughts, thereby clearly suggesting that all sentences employ predication, and that predication occurs in even the simplest thoughts. When Hanks says "the source" of truth conditions is to be found in "acts of predication" this suggests the general thesis: no predication, no truth conditions. Similarly, Soames' formulation suggests that for all propositions there could be, the unity of the proposition is due to the act of predication. These are very strong claims. Even if it could be plausibly maintained that predication is an element of all sentences we use, or thoughts we have, or that acts of predication are the source of all truth- 14 R. Heck, What is a Singular Term?, unpublished. Retrieved from http://rkheck.frege.org/pdf/unpublished/SingularTerms.pdf. 15 D. Davidson, Donald, Truth and Predication, Harvard University Press, Cambridge, Massachusetts 2005, p. 77. 16 P. Hanks, Propositional Content, Oxford University Press, Oxford 2015, p. 4. 17 S. Soames, What is Meaning?, Princeton University Press, Princeton, New Jersey 2010, p. 65. 9 conditions or propositions we express, it is on the face of it a much stronger claim that the same thing goes for all sentences, thoughts, truth-conditions or propositions there are, or could be. The evidence they have to go on concerns the former. But maybe, for all these authors argue for, there could be what I have called alien structure. 10. Conclusion What I have sought to do here is to raise the issue of the possibility of alien structure, try to make some progress on how to make sense of alien structure, and relate the issue of alien structure to some well-known themes from the history of analytic philosophy. I believe that the question of whether there can be alien structure are both deep and natural questions to ask. I further believe that investigations into this question are fruitful also because they shed light on other issues in metaphysics and philosophy of languages. In this short paper I have tried to show this.