Caglan Cinar Dilek
Oxford University Press
2017
Hardback £30.00
288
Reviewed by: Çağlan Çınar Dilek (Central European University)
I, Me, Mine: Back to Kant, and Back Again by Beatrice Longuenesse presents a comprehensive study on different understandings of the notion of ’I’ through focusing particularly on how ‘I’ is used by Kant in ‘I think’ and comparing it with its usage by Descartes, Wittgenstein, and Sartre. This book presents the provocative claim that Freud is a good candidate for being a descendant of Kant by naturalizing his view of ‘I’. The book consists of three parts. Firstly, the author starts with a comparative analysis of ‘consciousness as a subject’ in Kant, ‘usage of I’ in Wittgenstein and ‘pre-reflective cogito’ in Sartre. Then she moves back to Kant’s understanding of ‘I’ in ‘I think’ and in ‘I ought to’ through his criticism of rationalist ideas on the nature of ‘I’ as a substance, as simple, and as a person. Lastly she presents how Freud’s notions of ‘ego’ and ‘superego’ have similarities to Kant’s ‘I think’ and ‘I ought’ and how Freud can naturalize Kant’s transcendental philosophy.
Longuenesse does not intend to give an historical study but rather aims to present a strong Kantian picture of ‘I’ that is most loyal to him and also strongest in today’s discussions, as the topic fits nicely into the contemporary discussions in philosophy of mind and language. The choice of historical figures in this sense works towards a better understanding of the intended strong Kantian position. In this direction, Descartes’ argument against skepticism for the existence of ‘self’ provides also a foundational starting point for the peculiarity of ‘I’ in ‘I think’ – that we necessarily experience ourselves as a simple substance and as a person with diachronical unity, but we cannot infer these qualities of the ‘I’ as an object as conceived by rationalists. While Wittgenstein’s distinction between ‘use of I as subject’ and ‘use of I as object’ has framed discussions in philosophy of language on self-ascription and the referent of ‘I’, phenomenological ideas like ‘pre-reflective consciousness’ have made a great influence in the philosophy of mind and consciousness in last decades, reviving a move towards One-Level Accounts of Consciousness in contrast to Higher-Order Representational Theories of Consciousness. And Freud’s notions help us to understand Kant’s ‘I’ in his theoretical and practical philosophy in an embedded and embodied context.
In the first part (Chapters 2 and 3), Longuenesse starts by treating self-consciousness as a first-person usage of ‘I’. In this direction, she introduces Wittgenstein’s distinction between two uses of ‘I’: ‘the use as an object’ and ‘the use as subject’. The author then compares this distinction by Wittgenstein with Kant’s distinction between ‘consciousness of oneself as subject’ and ‘consciousness of oneself as object.’ For Wittgenstein, the ‘use of I as object’ is exemplified in cases where you utter sentences like “my arm is broken,” “I have grown six inches,” while the ‘use of I as subject’ is exemplified as you say “I see so and so,” “I think it will rain,” and “I have toothache”. The distinguishing feature of the ‘use of I as a subject’ is that there is no possibility of error, while there is one in the ‘use of I as object’. Shoemaker describes this by saying ‘the use of I as subject’ is “immune to error through misidentification relative to first-person pronoun” and Longuenesse goes along with this description throughout the book while treating Wittgenstein’s notion. Accordingly, even when ‘I’ actually refers to ‘oneself as an object’ and that person later infers that the mentioned subject is identical to himself (as in John Perry’s example where he finds out that the person who is making a mess in the market turns out to be himself), the final criterion for finding out the truth about the statement (person x = ‘I’) is not objective. Rather, “there needs to be a point at which no more search for objective criteria is called for in order to establish the identity between the entity of which the predicate is true, and the believer and speaker of the current thought asserting the predicate to be true.” To establish this, the believer should have a special access to information about herself.
Longuenesse argues that even the ‘use of I as object’ depends on the kind of information that, expressed in a judgment, would ground a ‘use of I as a subject’. So, the question becomes what this ‘I as subject refers to’ (of course if it refers to anything at all; Anscombe argues that it does not, but Longuenesse argues against such a position). Evans thinks that the referent is the embodied entity. Accordingly, self-ascriptions, which are immune to error through misidentification (IEM), “are not limited to mental states but include bodily mental states.” For him, the referent as an embodied entity constitutes the conditions of the possibility for a referential use of ‘I’. He makes use of Kant’s ‘I’ as accompanying all our perceptions, and argues that without such an embodied and embedded referent we end up with at most a formal ‘I think”. It follows that ‘I’ in ‘I think’ represents only “a form of thought and it is not used to refer to any entity at all.” Longuenesse agrees with Evans on emphasizing the role of the embodied entity, while she disagrees that Evans’ claim about the referent of ‘I’ is true, both as a Kantian interpretation and as a claim in itself. According to Longuenesse, it is right only to say that in the lack of information about the properties of the referent of ‘I’, one cannot derive any property ‘I’ refers to. Nevertheless, this does not mean that ‘I’ in ‘I think’ does not refer to any entity at all. This is an important point on which Longuenesse builds the second part of the book where she treats Kant’s criticisms of rationalist claims about the nature of ‘I’. Accordingly, Kant denies that we can infer the properties of the ‘I’ – as being a substance, simple and a person, as claimed by rationalists, while he does not deny that ‘I’ refers to any such entity at all.
Longuenesse thinks that Kant`s distinction between ‘consciousness as a subject’ and ‘consciousness as an object’ does not match Wittgenstein’s distinction. The ‘use of I as a subject’ that grounds all the uses of I (as an object or subject) is better understood through the Kantian notion of ‘transcendental unity of self-consciousness’, which maps only a part of Wittgenstein`s ‘use of I as a subject’ – as in ‘I think’. So one needs to distinguish different uses of I as subject: 1) self-location, 2) self-ascription of bodily predicates, 3) self-ascription of P predicates and 4) the unity of `I’ that grounds `I think’. The fourth kind of self-consciousness on which ‘I think p` rests is presupposed in all other uses of I and is a necessary condition for any use of I and any judgment.
Chapter 3 is devoted to different uses of ‘I’ as a subject, this time from a phenomenological perspective, and continues to investigate its relation to ‘I’ as an embodied entity. Longuenesse makes use of Sartre`s distinction between ‘non-thetic/non-positional’ consciousness and ‘thetic/positional’ consciousness. ‘Non-thetic consciousness’ accompanies all consciousness that is directed to an object, and it is omnipresent, while it is not itself taken as an object (which is the case in thetic consciousness). Thetic consciousness is a reflective kind of consciousness where one`s attention is directed to the non-thetic consciousness. Sartre considers both the awareness of one`s own body (body-for-itself) and awareness of the unity of mental activity (pre-reflective cogito) as forms of non-positional consciousness. Longuenesse makes a comparative analysis between Sartre`s ‘pre-reflective cogito’, Wittgenstein`s ‘use of I as subject’ and Kant`s ‘consciousness of oneself as a subject’. She argues that Sartre`s and Wittgenstein`s notions share the weaknesses vis-a-vis Kant`s notion: Sartre and Wittgenstein defend stronger and broader claims than Kant by aiming to offer an account of the kinds of self-awareness that back all cases of the use of I as subject, but then they fall into a contradictory position. Kant`s position is stronger by presenting a less comprehensive position: it only tries to back the ‘use of I as subject’, which is then considered as a ground for other kinds of uses of I (like of our body).
It is interesting to see a comparison between Kant and Sartre that also includes Wittgenstein, if we consider recent discussions on consciousness in philosophy of mind. Phenomenology has been having an effect on theories of phenomenal consciousness in the last decades, through using ideas by Husserl, Merleau-Ponty, and Sartre. Dan Zahavi has been one of the pioneers to bring these ideas back to analytical philosophy to argue against representational theories – particularly Higher-Order Representational Theories. An important focus of attack of such phenomenological approaches is David Rosenthal with his classical Higher-Order Thought Theory. He argues that one can explain what-is-like-ness, a subject’s being phenomenally conscious of being in a mental state, through explaining state-consciousness. State-consciousness of a particular state that is directed to the worldly object is explained through a higher-order mental state, which is thought-like in form and makes the first-order mental state conscious by representing it in an immediate and non-inferential manner. Without the presence of such an occurrent Higher-Order Thought (HOT), our first-order mental state is not conscious and there is nothing-it-is-like to undergo that particular mental state. This state has still the property of ‘mentality’ as having a particular qualitative object as its content and this is explained though a theory of mentality, distinct from a theory of consciousness. Dan Zahavi argues against such an approach by using notions from the phenomenological tradition such as ‘mineness’, ‘subjectivity’, ‘first-person perspective’, and ‘pre-reflective consciousness’. The essential idea is that there is always a form of pre-reflective consciousness present in our experience, for which a higher-order representation is not necessary and even destructive to understand that particular phenomenological consciousness, because representation changes the nature of conscious experience by objectifying and thus modifying it. This pre-reflective consciousness makes an experience ‘for-me’, through which I experience the world and of which I am always aware. Thus, this is at the same time a form of self-consciousness: there would not be any form of self-consciousness possible without the minimal, pre-reflective consciousness, and we don’t need to give a different account for self-consciousness by explaining it through meta-representation or reflexivity.
It is important for such a discussion that Longuenesse points to the relation between a Kantian ‘I’ in ‘I think’ as the condition of possibility for any experience and ‘pre-reflective cogito’ as the condition for Cartesian ‘cogito’. But the similarities are not limited to this: both in Sartre and Kant ‘I’ is not an object, the representation of which falls under the concept ‘I think’/cogito, but rather ‘I think’ is “the very expression of the act of thinking.” This emphasis is again important to consider the activity and the subject of activity together. Only by understanding this interrelatedness is it possible to discuss the subject of experience in a proper way, for which phenomenology has had important effect against theories distinguishing between subject and its experience (and which then try to understand how an experience belongs to a self and how the unity of self is constituted through distinct theories), and against views which treat ‘I’ as representation as the outcome of a developed ability of concept usage.
The second part of the book (Chapters 4, 5 and 6) deals with the Cartesian ‘cogito, ergo sum’ and with the question of whether we can infer anything about the nature of ‘I’. Kant accuses “Descartes and his rationalist followers for having been under the illusion that they could derive not only ‘I exist’, but also an answer to the question ‘What am I?’ from the mere consideration of the proposition ‘I think’” (74). Chapter 5 deals with the different reasons Descartes and Kant choose to infer from ‘thinking’ to ‘I think’ rather than ‘it thinks’. Chapters 5 and 6 deal with Kant`s refutations of rationalist arguments that `I’ is i) a substance , ii) simple, and iii) a person (with personal identity across time).
It is illuminating to see in Chapter 4 how far Descartes and Kant agree on the role of ‘I’, while they have different motivations to use ‘I think’ in their arguments. Longuenesse explains how Descartes deals with skeptical doubt and presents ‘I think’ as a foundational solution to it, while Kant responds to a Humean skepticism that is “primarily directed at the objective validity of the idea of causal connection.” According to Kant, for a representation to be possible or to be something to me, it should always be accompanied by the ‘I think’. Kant does not progress from there to “I think cannot be true unless ‘I’ is true”, nor does he infer the nature of ‘I’, but he rather moves to the claim that “all representations I ascribe to myself are so ascribed in virtue of being taken up in one and the same act of bonding and comparing them, an act that is determined according to some universal concepts of the understanding,” and the concept of causal connection is one of these with which Kant primarily deals. The author does a great job comparing the notion of thought and consciousness between these two philosophers in depth that is helpful towards any contemporary theory of consciousness, as lots of theories lack clear distinctions between different kinds of consciousness and how these relate to ‘thought’ and ‘I’. Accordingly, Descartes’ notion of ‘thought’ is broader than Kant’s in terms of including any occurrent mental state, while Kant refers only to conceptual representations, particularly to judgments.
Longuenesse’s categorization of three kinds of consciousness in Kant is useful to compare him with Descartes and Sartre: 1) the mere consciousness of the act of thinking, 2) the indeterminate perception that I think, 3) the empirically determined consciousness of the sequence of one’s mental states. The first one is self-consciousness as consciousness of the pure act of thinking. We cannot represent it as an object and we cannot categorize it. We cannot infer anything about its essence, even if we cognize it as the subject and ground of thinking. This spontaneous consciousness is considered similar to Sartre’s ‘pre-reflective cogito’. The latter kind of consciousness is an empirical intuition, “a mere perception of an act of thinking I take to be mine.” It has ‘time’ as its form and ‘sensation’ as its matter that is constituted of affecting oneself with one’s own act of thinking. This propositional ‘I think’ is located in time in relation to other perceptions but it remains indeterminate in so far as it is not. The third one is a “consciousness of my own existence in time as a thinking being” and here ‘I think’ contains ‘I exist.’ Longuenesse compares this explicit reflection on the sequence of my thoughts with Sartre’s ‘reflective self-consciousness’. The first kind of consciousness provides an immediate consciousness of myself, while the third kind of consciousness plays an important role to refute Descartes’ idealism. Descartes establishes the epistemic certainty of ‘I think’ through the identity between ‘perceiving that one thinks’ and ‘thinking’, and then infers ‘I exist’ from ‘I think’. On the other hand, Kant does not need such a move by considering ‘I think’ as a Cartesian, simple inspection of mind, because his argument is that ‘I think’ just means ‘I exist thinking’. Kant secures our knowledge of ‘I think’ through ‘perceiving that I think’, but he characterizes that perception as an act of self-affection differently from Descartes. So Longuenesse argues that there are more similarities than supposed between Descartes and Kant, while she shows that Kant essentially differs from Descartes by arguing that the consciousness of my thinking that grounds the consciousness of my own existence does not show anything about the nature of ‘I’. From the premise that ‘I think’ includes ‘I exist’, it does not follow the conclusion that “I exist merely as a thinking being distinct from my body.” This entity only refers to the individual currently thinking the proposition in which ‘I’ is used.
Chapter 5 deals with Kant’s argumentation against the ‘Paralogism of Substantiality’ and ‘Paralogism of Simplicity’ – fallacious arguments used by the rationalists towards the nature of ‘I’, respectively, that it is a substance and that it is simple. For Kant, they make use of a middle term, which has a “different meaning in [the] major and minor premise[s].” This is the reason they make syllogistic inferences from the apparently same concept that has in fact two different meanings. Kant aims to analyze these different meanings to show how rationalist arguments are valid in appearance but in fact invalid.
According to Kant’s formulation, the rationalist arguments have a ‘major premise’, a ‘minor premise’ and a ‘conclusion’. In the Paralogism of Substantiality, rationalists refer from the major premise that a subject that cannot be thought of something other than a subject as it cannot be a predicate of something else, and the minor premise that ‘I’ as thinking can only be thought of as a subject and cannot be predicated of something else to the conclusion that ‘I’ as thinking is a substance. However, there is a difference between saying ”I can only think of myself under the concept of substance” and “I am a substance,” where Kant agrees with the former claim and rationalists infer the latter one. For Kant, the minor premise is wrongly constructed to lead to an invalid inference from major premise and minor premise to the conclusion: The “entity thought under the concept ‘I’ is represented as an absolute subject only in a logical sense.” While ‘subject’ in the major premise refers to an absolute subject, ‘subject’ in the minor premise refers to a ‘logical subject’ – the substantiality of the subject is only represented to the subject itself. Hence ‘subject’ (and thus substance) that is used as a middle term by rationalists is actually not a middle term at all. Similarly, in the Paralogism of Simplicity, from the major premise “that something whose action can never be regarded as the concurrence of many acting things, is simple”; and the minor premise that “‘I’, as thinking, am something whose action can never be regarded as the concurrence of many acting things”; the conclusion “So I, as thinking, am simple” is inferred. Again, the concept ‘I’ is only logically simple and the subject thought under the concept ‘I’ is necessarily thought to be simple because “its action is thought to be indivisibly one.” However, the simplicity of the subject of the action is represented only to that subject itself.
Longuenesse infers from these discussions a positive Kantian idea that has found its place in contemporary philosophy of mind in the distinction between the “first-person standpoint and third-person standpoint”. Accordingly, the entity that represents itself under ‘I’ necessarily represents itself as an existing thing (substance), as indivisibly present in all its thoughts (simple), but ‘this first-person standpoint’, however universally indispensable to the act of thinking, tells us nothing about the objective nature of the thing that thinks” (131). That Longuenesse considers this distinction as the positive Kantian idea is valuable when we consider the discussions in contemporary philosophy of mind, epistemology and science on the question whether one should apply a special first-person methodology for a research on consciousness, or whether one can give a scientific and/or reductive explanation of consciousness with a third-person methodology that is used by science and on other philosophical notions.
In Chapter 6, the focus is Kant’s argument against ‘Paralogism of Personality’ – the claim that ‘I’ is a person. For Kant, the rationalist argument has a similar structure, inferring from the major premise that someone conscious of the numerical identity of itself in different times is a person, and the minor premise that ‘I’ as thinking is conscious of the numerical identity of itself in different time, to the conclusion that ‘I’ am a person. Again, Kant accepts the major premise and he is in favor of an idea of person that is diachronically synchronous contrary to the Lockean idea of person whose memory is enough to establish psychological continuity. However, Kant rejects the idea that the consciousness of identity expressed by the use of ‘I’ in ‘I think’ is sufficient to infer that I am, as an existing entity, a person. Longuenesse sums up this issue nicely as follows:
So the paradox of ‘I’ is this: ‘I’, as used in ‘I think, refers to an existing thinking, known by the I-user (the thinker) to exist, in virtue of the fact that the I-user, in each instance of thinking knows herself to exist. ‘I’, as used in ‘I think’, is even the only purely intellectual concept that does give access to an existing thinking. But if, from the way we think of ourselves in using ‘I’ in ‘I’ think, we infer there is an object that we take to be, as a thinking thing, a substance, simple, and numerically identical through time, then we make a mistake: that object is a fiction. The error of the rationalist metaphysician (the error of Kant himself in his pre-critical incarnation) is to insist that on the basis of the thought ‘I’ think we have sufficient ground to assert that the fictitious object of that representation is transcendentally real: real in itself. The mere thought ‘I think’ in fact provides no such ground (164).
What is especially different in the discussion about personality is that Kant enriches the concept of personality by focusing on moral personality in addition to psychological personality. Moral personality is dependent on two components: i) “being an empirically determined, persisting entity, conscious of its own numerical identity through time, and ii) having the capacity to prescribe the moral to oneself, as the principle under which one’s maxims are determined.” Without an understanding of moral personality, it is not possible to comprehend Kant’s criticism of Syllogism of Personality and also his full picture of ‘I’ in general. This notion also relates previous discussions in the book to Longuenesse’s important final claim in the last part (Chapters 7 and 8) that Freud can be considered in a sense a descendant of Kant, if we consider the parallels between Kant’s ‘I’ in ‘I think’ with Freud’s ‘ego’, and Kant’s ‘I ought to’ with ‘superego’. Kant’s ‘I’ in ‘I’ think, as the concept of ‘unity of apperception’, is an organization of mental processes governed by logical rules. This is a formal condition and Kant is known to assign this capacity “to an unknown and unknowable transcendental subject” (175). Kant’s methodology is clearly not empirical and the discussion is part of his transcendental philosophy, which constitutes a clear polarity to Freud’s empirical investigation and causal-developmental account of the capacity to think in the first person. Despite the differences, Longuenesse argues that we can see important similarities between them, and Freud can naturalize Kant’s transcendental subject.
The author considers the similarities under four points: Firstly, Kant’s ‘I’ in ‘I think’ (‘I’ as discursive thinking) has its counterpart in Freud’s ego. Kant’s ‘logical use of the understanding’ is similar to Freud’s ‘reality principle’. Ego functions in line with the ‘law of secondary processes’ according to this principle and it can conflict with ‘id’ and the ‘laws of primary processes’. “Intuitions are brought under concepts and then combined in judgments and inferences according to logical rules.” So, the differentiations Freud makes between ‘id’ and ‘Ego’; ‘laws of primary processes’ and ‘secondary processes’; ‘consciousness as an immediate quality of mental states’ and ‘consciousness as the property of mental states’ (whose content obeys the rules of the ego) can be compared to the distinctions Kant makes between different kinds of consciousness (as discussed in Chapter 5). The nature and function of ‘ego’ is parallel to the second notion of consciousness in Kant, “according to which I am conscious of a representation if it is taken up in the unity of consciousness that makes objective representation and thinking possible.” Secondly, there are parallels between Kant’s ‘synthesis of imagination’ and Freud’s perceptual images that are organized according to the rules of ego. Just as in Kant the discursive expression of the unity of consciousness in concepts and judgments presupposes a “prediscursive activity of combination or synthesis performed by the imagination,” in Freud perceptual images and representations of imagination are subject to the rule of the ego, and if they are pre-conscious, these images can become conscious only if they are associated with words. Thirdly, Kant and Freud have parallel views on the mental activities of which we are generally not conscious. For Kant, there is no thought without language and intuitions are blind if they are not subsumed under concepts. In Freud, “access to words is the way a representation enters the realm of reason and level-headedness.” Kant emphasizes that qualitative or intentional consciousness of the working of our imagination is blind (not conscious), while Freud also argues that “the complex operations that go on in our minds are mostly unconscious.” Fourthly, it is necessary for Kant that ‘I’ is represented as an object in the world. The transcendental unity of apperception gets information of the body via the sensory information carried by a bodily state. Freud also argues that “the ego is first and foremost a bodily ego” and thus the emphasis on embodiment of ‘I’ in Kant and ‘ego’ in Freud is again parallel.
Freud’s naturalization of ego makes use of ‘second nature’ as the developmental account he presents on the occurrence of ego happens in a social context. This structure that includes the social aspects of this developmental process is understood through his notion of ’super-ego’ (ego-ideal). This is in accordance with the notion of ‘I’ in Kant’s ‘I ought to’ and his account of ‘personality’ that includes a moral self (as dealt in Chapter 6). The argument on this similarity between Kant and Freud has the same structure: just as we can give a causal-development account of Kant’s ‘I’ in ‘I think’ through Freud’s ‘Ego’, we can do the same of ‘I ought to’ through Freud’s ‘super-ego’, which “can be seen as providing a developmental story for the conflicted structure of mental life that grounds, according to Kant, the use of ‘I’ in the moral ‘I ought to’” (226). Freud considers Kant’s ‘categorical imperative’ as the direct heir of ‘Oedipus complex’ – as an unconditional normative constraint on the ego. Freud explains the practice of reason-giving and justification as characteristic of a developed ego, and gives a causal history of the idea of categorical imperative through the development of ideas from eigtheenth-century rationalistic philosophy. More than that, just as Kant considers the manifestation of moral attitude primarily through a feeling of respect, there is also a moral feeling at work in Freud’s picture on “curbing libido and aggression,” which he calls the “supra-personal side of human nature” (221). Another point is that in both pictures we have blindness to one’s real motives. Even if this blindness is to be treated in different ways, there is one thing in common: Freud’s ‘unconscious’ and Kant’s ‘motivated blindness’ both refer to our lack of knowledge of our real motives for performing an action, even in cases when we believe we acted upon a universal maxim. Lastly, the relation between ego and body is comparable to the way Kant indexes transcendental unity of apperception to a particular body.
After showing the similarities and differences, Longuenesse ends up with the claim that Freud gives us a naturalized account of Kant’s picture of ‘I’: firstly, in Freud we do not need to refer to an unknown and unknowable transcendental subject to explain ‘I’ in ‘I think’ and ‘I ought to’. Secondly, a developmental history is presented to our capacity to settle norms of cognition and practical agency. Thirdly, second nature is naturalized. The contents of our norms are constituted by the internalization of parental figures and (through language) by the social and symbolic tools, rather than by our relation to nature. All of these parallel points present us a path to understand a non-transcendental subject through relating bodily and transcendental self in an empirical way, while also doing justice to a Kantian, broad understanding of ‘I’ by including psychological and moral self under the study of self.
Longuenesse’s book does not only provide us with a deeper and enriched understanding of Kant’s understanding of ‘I’, but it is also packed with many insightful ideas about how we can relate different notions of various philosophers from different paradigms and disciplines. She fills in the gaps within the history of philosophy to get a better understanding of contrary positions both within a particular time-period and across time, and traces back many important distinctions and ideas in contemporary philosophy of mind to Kant. This is a special source for anyone working in Kant for sure, but other than that it will also be an invaluable source for philosophers of mind and language and epistemologists who work in any aspect of self and consciousness such as phenomenal consciousness, phenomenology of our experience, the nature of self, first-person perspective, unity of self, first-person usage of ‘I’, personal identity, agency and moral self, and ego. I believe it will lead to further analysis of Kant under the auspices of such contemporary discussions, and it will motivate further comparisons between Kant and other historical figures. Most importantly, her treatment of Kant through Freud’s ego and superego opens up a new dimension of discussion, and as her argumentation has a deep and solid structure, it is not easy for anyone working in philosophy of mind and ethics to stay unresponsive to this provocative and thought-provoking comparative analysis.