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How Analytic Philosophy Has Failed Cognitive Science

How Analytic Philosophy Has Failed Cognitive Science

Publisher: www.pitt.edu
English

This book is corrected and edited by Al-Hassanain (p) Institue for Islamic Heritage and Thought

How Analytic Philosophy Has Failed Cognitive Science

April 13, 2008

Contents

I. Introduction 3

II. First Distinction: From Labeling to Describing 5

III: Ingredient vs. Free-Standing Content: Semantically Separating Content from Force 10

IV. Simple versus Complex Predicates 16

V. Conclusion 20

Notes 24

I. Introduction

We analytic philosophers have signally failed our colleagues in cognitive science.  We have done that by not sharing central lessons about the nature of concepts, concept-use, and conceptual content that have been entrusted to our care and feeding for more than a century.

I take it that analytic philosophy began with the birth of the new logic that Gottlob Frege introduced in his seminal 1879Begriffsschrift .  The idea, taken up and championed to begin with by Bertrand Russell, was that the fundamental insights and tools Frege made available there, and developed and deployed through the 1890s, could be applied throughout philosophy to advance our understanding of understanding and of thought in general, by advancing our understanding of concepts - including the particular concepts with which the philosophical tradition had wrestled since its inception.  For Frege brought about a revolution not just inlogic , but insemantics .  He made possible for the first time amathematical characterization of meaning and conceptual content, and so of the structure of sapience itself.  Henceforth it was to be the business of the new movement of analytic philosophy to explore and amplify those ideas, to exploit and apply them wherever they could do the most good.  Those ideas are the cultural birthright, heritage, and responsibility of analytic philosophers.  But we have not done right by them.  For we have failed to communicate some of the most basic of those ideas, failed to explain their significance, failed to make them available in forms usable by those working in allied disciplines who are also professionally concerned to understand the nature of thought, minds, and reason.

       Contemporary cognitive science is a house with many mansions.  The provinces I mean particularly to be addressing are cognitive psychology, developmental psychology, animal psychology (especially primatology), and artificial intelligence.  (To be sure, this is not all of cognitive science.  But the points I will be making in this paper are not of similarly immediate significance for such other subfields as neurophysiology, linguistics, perceptual psychology, learning theory, and the study of the mechanisms of memory.)  Cognitive psychology aims at reverse-engineering the human mind: figuring out how we do what we do, what more basic abilities are recruited and deployed (and how) so as to result in the higher cognitive abilities we actually display.  Developmental psychology investigates the sequence of stages by which those abilities emerge from more primitive versions as individual humans mature.  Animal psychology, as I am construing it, is a sort of combination of cognitive psychology of non-human intelligences and a phylogenetic version of ontogenetic human developmental psychology.  By contrast to all these empirical inquiries into actual cognition, artificial intelligence swings free of questions about how any actual organisms do what they do, and asks instead what constellation of abilities of the sort we know how to implement in artifacts might in principle yield sapience.

       Each of these disciplines is in its own way concerned with the empirical question of how the trick of cognition is or might be done.  Philosophers are concerned with the normative question of what counts as doing it - with what understanding, particularly discursive, conceptual understanding consists in, rather than how creatures with a particular contingent constitution, history, and armamentarium of basic abilities come to exhibit it.  I think Frege taught us three fundamental lessons about the structure of concepts, and hence about all possible abilities that deserve to count as concept-using abilities.[1]  The conclusion we should draw from his discoveries is that concept-use is intrinsically stratified.  It exhibits at least four basic layers, with each capacity to deploy concepts in a more sophisticated sense of ‘concept’ structurally presupposing the capacities to use concepts in all of the more primitive senses.  The three lessons that generate the structural hierarchy oblige us to distinguish between:

concepts that onlylabel and concepts thatdescribe ,

thecontent of concepts and theforce of applying them, and

concepts expressible already bysimple predicates and concepts expressible only bycomplex predicates.

AI researchers and cognitive, developmental, and animal psychologists need to take account of the different grades of conceptual content made visible by these distinctions, both in order to be clear about the topic they are investigating (if they are to tell us how the trick is done, they must be clear about exactly which trick it is) and because the empirical and in-principle possibilities are constrained by the way the abilities to deploy concepts in these various senses structurally presuppose the others that appear earlier in the sequence.  This is a point they have long appreciated on the side of basicsyntactic complexity.  But the at least equally important - and I would argue more conceptually fundamental - hierarchy ofsemantic complexity has been largely ignored.

II. First Distinction: From Labeling to Describing

The Early Modern philosophical tradition was built around aclassificatory theory of consciousness and (hence) of concepts, in part the result of what its scholastic predecessors had made of their central notion of Aristotelian forms.  The paradigmatic cognitive act is understood as classifying: taking something particularas being of some general kind.  Concepts are identified with those general kinds.

This conception was enshrined in the order of logical explanation (originating in Aristotle’sPrior Analytics ) that was common toeveryone thinking about concepts and consciousness in the period leading up to Kant.  At its base is a doctrine ofterms orconcepts , particular and general.  The next layer, erected on that base, is a doctrine ofjudgments , describing the kinds of classificatory relations that are possible among such terms.  For instance, besides classifying Socrates as human, humans can be classified as mortal.  Finally, in terms of those metaclassifications grouping judgments into kinds according to the sorts of terms they relate, a doctrine ofconsequences orsyllogisms is propounded, classifying valid inferences into kinds, depending on which classes of classificatory judgments their premises and conclusions fall under.

It is the master-idea ofclassification that gives this traditional order of explanation its distinctive shape.  That idea defines its base, the relation between its layers, and the theoretical aspiration that animates the whole line of thought: finding suitable ways of classifying terms and judgments (classifiers and classifications) so as to be able to classify inferences as good or bad solely in virtue of the kinds of classifications they involve.  The fundamental metaconceptual role it plays in structuring philosophical thought about thought evidently made understanding the concept ofclassifying itself a particularly urgent philosophical task.  Besides asking what differentiates various kinds of classifying, we can ask what they have in common.  What is it one mustdo in order thereby to count asclassifying something as being of some kind?

In the most general sense, one classifies something simply by responding to it differentially.  Stimuli are grouped into kinds by the response-kinds they tend to elicit.  In this sense, a chunk of iron classifies its environments into kinds by rusting in some of them and not others, increasing or decreasing its temperature, shattering or remaining intact.  As is evident from this example, if classifying is just exercising a reliable differential responsive disposition, it is a ubiquitous feature of the inanimate world.  For that very reason, classifying in this generic sense is not an attractive candidate for identification with conceptual, cognitive, or conscious activity.  It doesn’t draw the right line between thinking and all sorts of thoughtless activities.  Pan-psychism is too high a price to pay for cognitive naturalism.

That need not mean that takingdifferential responsiveness as the genus of whichconceptual classification is a species is a bad idea, however.  A favorite idea of the classical British empiricists was to require that the classifying response be entering asentient state.  The intrinsic characters of these sentient states are supposed to sort them immediately into repeatable kinds.  These are called on to function as theparticular terms in the base level of the neo-Aristotelian logical hierarchy.  General terms or concepts are then thought of as sentient state-kinds derived from the particular sentient state-kinds by a process ofabstraction : grouping the base-level sentient state-repeatables into higher-level sentient state-repeatables by some sort of perceivedsimilarity .  This abstractive grouping by similarity is itself a kind of classification.  The result is a path from one sort of consciousness, sentience, to a conception of another sort of consciousness, sapience, or conceptual consciousness.

A standing felt difficulty with this empiricist strategy is the problem of giving a suitably naturalistic account of the notion ofsentient awareness on which it relies.  Recent information-theoretic accounts of representation (under which heading I include not just Fred Dretske’s theory, which actually goes by that name, but others such as Jerry Fodor’s asymmetric counterfactual dependence and nomological locking models[2]) develop the same basic differential responsiveness version of the classic classificatory idea in wholly naturalistic modal terms.  They focus on the information conveyed about stimuli - the way they are grouped into repeatables - by their reliably eliciting a response of one rather than another repeatable response-kind from some system.  In this setting, unpalatable pan-psychism can be avoided not, as with traditional empiricism, by insisting that the responses be sentient states, but for instance by restricting attention to flexible systems, capable in principle of coming to encode many different groupings of stimuli, with a process oflearning determining what classificatory dispositions each one actually acquires.  (The classical American pragmatists’ program for a naturalistic empiricism had at its core the idea that the structure common to evolutionary development and individual learning is a Test-Operate-Test-Exit negative feedback process of acquiring practical habits, including discriminative ones.[3])

Classification as the exercise of reliable differential responsive dispositions (however acquired) is not by itself yet a good candidate forconceptual classification, in the basic sense in which applying a concept to something isdescribing it.  Why not?  Suppose one were given a wand, and told that the light on the handle would go on if and only if what the wand was pointed at had the property of beinggrivey .  One might then determine empirically that speakers are grivey, but microphones not, doorknobs are but windowshades are not, cats are and dogs are not, and so on.  One is then in a position reliably, perhaps even infallibly, to apply thelabel ‘grivey’.  Is one also in a position todescribe thingsas grivey?  Ought what one is doing to qualify as applying theconcept grivey to things?  Intuitively, the trouble is that one does not know what one has found out when one has found out that something is grivey, does not know what one is taking it to be when one takes it to be grivey, does not know what one is describing itas .  The label is, we want to say, uninformative.

What more is required?  Wilfrid Sellars gives this succinct, and I believe correct, answer:

It is only because the expressions in terms of which we describe objects, even such basic expressions as words for the perceptible characteristics of molar objects, locate these objects in a space of implications, that they describe at all, rather than merely label.[4]

The reason ‘grivey’ is merely alabel , that it classifies without informing, is that nothingfollows from so classifying an object.  If I discover that all the boxes in the attic I am charged with cleaning out have been labeled with red, yellow, or green stickers, all I learn is that those labeled with the same color sharesome property.  To learn what theymean is to learn, for instance, that the owner put a red label on boxes to be discarded, green on those to be retained, and yellow on those that needed further sorting and decision.  Once I know whatfollows from affixing one rather than another label, I can understand them not asmere labels, but asdescriptions of the boxes to which they are applied.  Description is classification withconsequences , either immediately practical (“to be discarded/examined/kept”) or for further classifications.

Michael Dummett argues generally that to be understood as conceptually contentful, expressions must have not onlycircumstances of appropriate application, but also appropriateconsequences of application.[5]  That is, one must look not onlyupstream , to the circumstances (inferential and non-inferential) in which it is appropriate to apply the expression, but alsodownstream to the consequences (inferential and non-inferential) of doing so, in order to grasp the content it expresses.  One-sided theories of meaning, which seize on one aspect to the exclusion of the other, are bound to be defective, for they omit aspects of the use that are essential to meaning.  For instance, expressions can have the same circumstances of application, and different consequences of application.  When they do, they will have different descriptive content.

1]    I will write a book about Hegel,

and

2]    I foresee that I will write a book about Hegel,

say different things about the world, describe it as being different ways.  The first describes my future activity and accomplishment, the second my present aspiration.  Yet the circumstances under which it is appropriate or warranted to assert them - the situations to which I ought reliably to respond by endorsing them - are the same (or at least, can be made so by light regimentation of a prediction-expressing use of ‘foresee’).  Here, to say that they have different descriptive content can be put by saying that they have different truth conditions.  (That they have the same assertibility conditions just shows how assertibility theories of meaning, as one-sided in Dummett’s sense, go wrong.)  But that same fact shows up in the different positions they occupy in the “space of implications.”  For from the former it follows that I will not be immediately struck by lightning, that I will write some book, and, indeed, that I will write a book about Hegel.  None of these is in the same sense a consequence of the second claim.

       We might train a parrot reliably to respond differentially to the visible presence of red things by squawking “That’s red.”  It would not yet bedescribing things as red, would not be applying the conceptred to them, because the noise it makes has no significance for it.  It does not know that it follows from something’s being red that it is colored, that it cannot be wholly green, and so on.  Ignorant as it is of those inferential consequences, the parrot does not grasp the concept (any more than we express a concept by ‘grivey’).  The lesson is that even observational concepts, whose principal circumstances of appropriate application are non-inferential (a matter of reliable dispositions to respond differentially to non-linguistic stimuli) must have inferential consequences in order to make possible description, as opposed to the sort of classification effected by non-conceptual labels.

The rationalist idea that the inferential significance of a state or expression is essential to itsconceptual contentfulness is one of the central insights of Frege’s 1879Begriffsschrift (“concept writing”) - the founding document of modern logic and semantics - and is appealed to by him in the opening paragraphs to define his topic:

...there are two ways in which the content of two judgments may differ; it may, or it may not, be the case that all inferences that can be drawn from the first  judgment when combined with certain other ones can always also be drawn from the second when combined with the same other judgments…I call that part of the content that is the same in both the conceptual content [begriffliche Inhalt].  [6]

Here, then, is the first lesson that analytic philosophy ought to have taught cognitive science:  there is a fundamental conceptual distinction between classification in the sense oflabeling and classification in the sense ofdescribing , and it consists in theinferential consequences of the classification: its capacity to serve as a premise in inferences (practical or theoretical) to further conclusions.  (Indeed, there are descriptive concepts that are purelytheoretical - such asgene andquark - in the sense that in addition to their inferential consequences of application, they haveonly inferentialcircumstances of application.)  There is probably no point in fighting over the minimal circumstances of application of the conceptsconcept andconceptual .  Those who wish to lower the bar sufficiently are welcome to consider purely classificatory labels as a kind of concept (perhaps so as not to be beastly to the beasts, or disqualify human infants, bits of our brains, or even some relatively complex computer programs wholly from engaging in conceptually articulated activities).  Butif they do so, they mustnot combine those circumstances of application with the consequences of application appropriate to genuinelydescriptive concepts - those thatdo come with inferential significances downstream from their application.

       Notice that this distinction between labeling and describing is untouched by two sorts of elaborations of the notion of labeling that have often been taken to be of great significance in thinking about concepts from the classical classificatory point of view.  One does not cross the boundary from labeling to describing just because the reliable capacity to respond differentially islearned , and in that sense flexible, rather thaninnate , and in that sense rigid.  And one is likewise developing the classical model in an orthogonal direction insofar as one focuses on the metacapacity to learn to distinguish arbitrary Boolean combinations of microfeatures one can already reliably discriminate.  From the point of view of the distinction between labeling and describing, that is not yet the capacity to formconcepts , but only the mastery ofcompound labels.  That sort of structural articulation upstream has nosemantic import at the level of description until and unless it is accorded a corresponding inferential significance downstream.

III: Ingredient vs. Free-Standing Content: Semantically Separating Content from Force

Once our attention has been directed at the significance of applying a classifying concept - downstream, at the consequences of applying it, rather than just upstream, at the repeatable it discriminates, the grouping it institutes - so thatmere classification is properly distinguished fromdescriptive classification, the necessity of distinguishing differentkinds of consequence becomes apparent.  One distinction in the vicinity, which has already been mentioned in passing, is that betweenpractical andtheoretical (or, better,cognitive ) consequences of application of a concept.  The significance of classifying an object by responding to it one way rather than another may be to make it appropriate todo something else with or to it - to keep it, examine it, or throw it away, to flee or pursue or consume it, for example.  This is still a matter of inference; in this case, it ispractical inferences that are at issue.   But an initial classification may also contribute to further classifications: that what is in my hand falls under both the classificationsraspberry andred makes it appropriate to classify it also asripe - which in turn has practical consequences of application (such as, under the right circumstances “falling to without further ado and eating it up,” as Hegel says in another connection) that neither of the other classifications has individually.  Important as the distinction between practical and cognitive inferential consequences is, in the present context there is reason to emphasize a different one.

       Discursive intentional phenomena (and their associated concepts), such as assertion, inference, judgment, experience, representation, perception, action, endorsement, and imagination typically involve what Sellars calls “the notorious ‘ing’/‘ed’ ambiguity.”  For under these headings we may be talking about theact of asserting, inferring, judging, experiencing, representing, perceiving, doing, endorsing, and imagining, or we may be talking about thecontent that is asserted, inferred, judged, experienced, represented, perceived, done, endorsed, or imagined.  ‘Description’ is one of these ambiguous terms (as is ‘classification’).  We ought to be aware of the distinction between the act of describing (or classifying), applying a concept, on the one hand, and the content of the description (classification, concept) -how things are described (classified, conceived) - on the other.  And the distinction is not merely of theoretical importance for those of us thinking systematically about concept use.  A distinctive level of conceptual sophistication is achieved by concept users that themselves distinguish between the contents of their concepts and their activity of applying them.  So one thing we might want to know about a system being studied, a non-human animal, a prelinguistic human, an artifact we are building, is whetherit distinguishes between theconcept it applies and what itdoes by applying it.

We can see a basic version of the distinction between semantic content and pragmatic force as in play whereverdifferent kinds of practical significance can be invested in thesame descriptive content (different sorts of speech act or mental act performed using that content).  Thus if a creature can not only say or think that the door is shut, but also ask or wonder whether the door is shut, or order or request that it be shut, we can see it as distinguishing in practice between the content being expressed and the pragmatic force being attached to it.  In effect, it can use descriptive contents to do more than merely describe.  But this sort of practical distinguishing of pragmatic from semantic components matters for the semantic hierarchy I am describing only when it is incorporated or reflected in theconcepts (that is, thecontents ) a creature can deploy.  The capacity to attach different sorts of pragmatic force to the same semantic content is not sufficient forthis advance in structural semantic complexity.  (Whether it is a necessary condition is a question I will not address - though I am inclined to think that in principle the answer is ‘No’.)

       For the inferential consequences of applying a classificatory concept, when doing that is describing and not merely labeling, can be eithersemantic consequences, which turn on thecontent of the concept being applied, orpragmatic consequences, which turn on theact one is performing in applying it.  Suppose John issues an observation report: “The traffic light is red.”  You may infer that it is operating and illuminated, and that traffic ought to stop in the direction it governs.  You may also infer that John has a visually unobstructed line of sight to the light, notices what color it is, and believes that it is red.  Unlike the former inferences, these are not inferences from what Johnsaid , from thecontent of his utterance, from the concepts he has applied.  They are inferences from hissaying it, from the pragmatic force or significance of hisuttering it, from the fact of hisapplying those concepts.  For what he hassaid , that the traffic light is red, could be true even if John had not been in a position to notice it or form any beliefs about it.  Nothing about John follows just from the color of the traffic light.[7]

       It can be controversial whether a particular consequence follows from how something is described or from describing it that way, that is, whether that consequence is part of the descriptive content of an expression, the concept applied, or stems rather from the force of using the expression, from applying the concept.  A famous example is expressivist theories of evaluative terms such as ‘good’.  In their most extreme form, they claim that these terms have no descriptive content.  All their consequences stem from what one is doing in using them: commending, endorsing, or approving.  In his lapidary article “Ascriptivism,”[8]Peter Geach asks what the rules governing this move are.  He offers the archaic term ‘macarize’, meaning to characterize someone as happy.  Should we say that in apparently describing someone as happy we are not really describing anyone, but rather performing the distinctive speech act of macarizing?  But why not then discern distinctive speech acts forany apparently descriptive term?

       What is wanted is a criterion for distinguishing semantic from pragmatic consequences, those that stem from the content of the concept being applied from those that stem from what we are doing in applying that concept (using an expression to perform a speech act).  Geach finds one in Frege, who in turn was developing a point made already by Kant.[9]  The logical tradition Kant inherited was built around the classificatory theory of consciousness we began by considering.  Judgment was understood as classification or predication: paradigmatically,of something particularas something general.  But we have put ourselves in a position to ask: is this intended as a model of judgeable contents are constructed, or of what one is doing in judging?  Kant saw, as Frege would see after him, that the phenomenon ofcompound judgments shows that it cannot play both roles.  For consider the hypothetical or conditional judgment

3]   If Frege is correct, then conceptual content depends on inferential consequences.

In asserting this sentence (endorsing its content), have I predicated correctness of Frege (classified him as correct)?  Have I described him as correct?  Have I applied the concept of correctness?  If so, then predicating or classifying (or describing) is not judging.  For in asserting the conditional I havenot judged or asserted that Frege is correct.  I have at most built up a judgeable content, the antecedent of the conditional, by predication.  For embedding a declarative descriptive sentence as an unasserted component in a compound asserted sentence strips off the pragmatic force its free-standing, unembedded occurrence would otherwise have had.  It now contributesonly itscontent to thecontent of the compound sentence, to which alone the pragmatic force of a speech act is attached.

       This means that embedding simpler sentences as components of compound sentences - paradigmatically, embedding them as antecedents of conditionals - is the way to discriminate consequences that derive from thecontent of a sentence from consequences that derive from theact of asserting or endorsing it.  We can tell that ‘happy’does express descriptive content, and isnot simply an indicator that some utterance has the pragmatic force or significance of macarizing, because wecan say things like:

4]    If she is happy, then John should be glad.

For in asserting that, one doesnot macarize anyone.  So the consequence, that John should be glad, must be due to the descriptive content of the antecedent, not to its force.

Similarly, Geach argues that the fact that we can say things like:

5]    If being trustworthy is good, then you have reason to be trustworthy,

shows that ‘good’does have descriptive content.[10]  Notice that this same test appropriately discriminates the different descriptive contents of the claims:

6]    Labeling is not describing,

and

7]    I believe that labeling is not describing.

For the two do not behave the same way as antecedents of conditionals.  The stuttering inference

8]    If labeling is not describing, then labeling is not describing,

is as solid an inference as one could ask for.  The corresponding conditional

9]    If I believe that labeling is not describing, then labeling is not describing,

requires a good deal more faith to endorse.  And in the same way, the embedding test distinguishes [1] and [2] above.  In each case it tells us, properly, that different descriptive contents are involved.

       What all this means is that any user of descriptive concepts who can also form compound sentences, paradigmatically conditionals, is in a position to distinguish what pertains to the semanticcontent of those descriptive concepts from what pertains to theact or pragmaticforce           of describing by applying those concepts.  This capacity is a new, higher, more sophisticated level of concept use.  It can be achievedonly by looking at compound sentences in which other descriptive sentences can occur as unasserted components.  For instance, it is only in such a context that one can distinguishdenial (a kind of speech act or attitude) fromnegation (a kind of content).  One who asserts [6] hasboth denied that labeling is describing,and negated a description.  But one who asserts conditionals such as [8] and [9] has negated descriptions, but hasnot denied anything.

       The modern philosophical tradition up to Frege took it for granted that there was an special attitude on could adopt towards a descriptive conceptual content, a kind of minimal force one could invest it with, that must be possible independently of and antecedent to being able to endorse that content in a judgment.  This is the attitude of merelyentertaining the description.  The picture (for instance, in Descartes) was thatfirst one entertained descriptive thoughts (judgeables), andthen , by an in-principle subsequent act of will, accepted or rejected it.  Frege rejects this picture.  The principal - and in principle fundamental - pragmatic attitude (and hence speech act) is judging or endorsing.[11]  The capacity merely to entertain a proposition (judgeable content, description) is a late-coming capacity - one that is parasitic on the capacity to endorse such contents.  In fact, for Frege, the capacity to entertain (without endorsement) the proposition thatp is just the capacity to endorseconditionals in which that proposition occurs as antecedent or consequent.  For that is to explore its descriptive content, its inferential circumstances and consequences of application, what it follows from and what follows from it, what would make it true and what would be true if it were true, without endorsing it.  This is a new kind of distanced attitude toward one’s concepts and their contents - one that becomes possible only in virtue of the capacity to form compound sentences of the kind of which conditionals are the paradigm.  It is a new level of cognitive achievement - not in the sense of a new kind of empirical knowledge (though conditionals can indeed codify new empirical discoveries), but of a new kind of semantic self-consciousness.

Conditionals make possible a new sort of hypothetical thought.  (Supposing that postulating a distinct attitude of supposing would enable one to dothis work, the work of conditionals, would be making the same mistake as thinking that denial can do the work of negation.)  Descriptive concepts bring empirical properties into view.  Embedding those concepts in conditionals brings the contents of those concepts into view.  Creatures that can do that are functioning at a higher cognitive and conceptual level than those who can only apply descriptive concepts, just as those who can do that are functioning at a higher cognitive and conceptual level than those who can only classify things by reliable responsive discrimination (that is, labeling).  That fact sets a question for the different branches of cognitive science I mentioned in my introduction.  Can chimps, or African grey parrots, or other non-human animals not just use concepts to describe things, but also semantically discriminate the contents of those concepts from the force of applying them, by using them not just in describing, but in conditionals, in which their contents are merely entertained and explored?  At what age, and along with what other capacities, do human children learn to do so?  What is required for a computer to demonstrate this level of cognitive functioning?

       Conditionals are special, because they makeinferences explicit - that is, put them into endorsable, judgeable, assertible, which is to say propositional form.  And it is their role in inferences, we saw, that distinguishes descriptive concepts from mere classifying labels.  But conditionals are an instance of a more general phenomenon.  For we can think of them as operators, which apply to sentences to yield further sentences.  As such, they bring into view a new notion of conceptual content: a new principle of assimilation, hence classification, of such contents.  For we begin with the idea of sameness of content that derives from sameness of pragmatic force, attitude, or speech act.  But the Frege-Geach argument shows that we can also individuate conceptual contents more finely, not just in terms of their role in free-standing utterances, but also accordingly as substituting one for another as arguments of operators (paradigmatically the conditional) does or does not yield compound sentences with the same free-standing pragmatic significance or force.  Dummett calls these notions “free-standing” and “ingredient” content (or sense), respectively.  Thus we might think that

10] It is nice here,

and

11]  It is nice where I am,

express the same attitude, perform the same speech act, have the same pragmatic force or significance.  They not only have the same circumstances of application, but the same consequences of application (and hence role as antecedents of conditionals).  But we can see that they have differentingredient contents by seeing that they behave differently as arguments when we apply another operator to them.  To use an example of Dummett’s,

12] It isalways nice here,

and

13] It isalways nice where I am,

have very different circumstances and consequences of application, different pragmatic significances, anddo behave differently as the antecedents of conditionals.  But this difference in content, this sense of “different content” in which they patently do have different contents, is one that shows uponly in the context of compounding operators, which apply to sentences and yield further sentences.  The capacity to deploy such operators to form new conceptual (descriptive) contents from old ones accordingly ushers in a new level of cognitive and conceptual functioning.

       Creatures that can not merely label, but describe arerational , in the minimal sense that they are able to treat one classification as providing areason for or against another.  If they can use conditionals, they can distinguish inferences that depend on thecontent of the concept they are applying from those that depend on what they aredoing in classifying something as falling under that concept.  But the capacity to use conditionals gives them more than just that ability.  For conditionals let themsay what is a reason for what, saythat an inference is a good one.  And for anyone who can do that, the capacity not just todeny that a classification is appropriate, but to use anegation operator to form new classificatory contents means brings with it the capacity to say that two classifications (classifiers, concepts) are incompatible: that one provides a reason to withhold the other.  Creatures that can use this sort of sentential compounding operator are not justrational , butlogical creatures.  They are capable of a distinctive kind ofconceptual self-consciousness .  For they can describe the rational relations that make their classifications into descriptions in the first place, hence be conscious or aware of them in the sense in which descriptive concepts allow them to be aware of empirical features of their world.