When discussing the theory of photography, great merit is accorded to the "index according to Peirce." Or, inversely, photography is illuminated to such an extent by the semiotics of the American philosopher that it must be the instance revealing certain shortcomings of the theory. As the six volumes of Peirce's 1930 Collected Papers are not readily available, we will cite from the excellent selection of texts by Justus Buchler in the Philosophical Writings, published by Dover in 1940. Emphasis is mine.

First and foremost, photographs as signs are ICONS, that is to say images or resemblances, which, to the scientist Charles Sanders Peirce, seem "very instructive" and "highly informative" ; "in certain respects they are exactly like the objects they represent". However, even faithful iconicity does not at all imply existence in the Peircean sense. It is a quality captured as a pure possible, as Tone, a monadic relation, Firstness, the field belonging to artists, according to potential mood.

But photographs as signs are also INDEXES, understood in terms of what we have been calling INDICES, which are linked through physical and causal relations between their objects: "they are physically forced to corresponds point by point to nature", and "the fact that it is known to be the effect of the radiations of the object renders it an index". Peircean indexicality pertains to Secondness, the domain of the pure event, the Token (mark), to the action-reaction in a dyadic relation, to "struggle", existence; it is the field belonging to businessmen, power and education, in accordance with the imperative or exclamatory mood.

In addition, Peirce also distinguishes a third category of signs, i.e. SYMBOLS, which suggest a "law" and which lead to the "argument", to inference, and to the triadic relation, of which Peirce the logician remarks that they can only be obtained from monads and dyads, as well as engendering all other types of relations (tetradic, pentadic and so on). This is the field of Thirdness, of Type, the field of the scholar. It is therefore Peirce's field, where Reality stretches out, where objects reticulate into a World thanks to a "fallible" Inquiry, in accordance with the declarative mood, while meeting the "pragmaticist" criterion: "I do not reason for the sake of my delight in reasoning, but solely to avoid disappointment and surprise". Thus, Peirce's God is real without existing, visible to the eye and heart: "as to God, open your eyes - and your heart, which is also a perceptive organ - and you see him". Do photographs partake of Peircean reality? He notes that he privileges "Dicent Sinsigns", which comprise "weathercocks" but also photographs which, as he tells us in passing, are a "mode of combination, or Syntax" of iconicity and indexicality, which "must be also significant".

In any case, with Peirce it is never the case that this or that sign is wholly an icon, an index, or a symbol. In the majority of his examples, the same sign can be an icon from one perspective and an index from another, while being a symbol from yet another angle, while all of these aspects are in themselves still "of a peculiar kind," depending on whether other "respects" interact. In brief, Peircean classifications are directed towards formal objects rather than material objects in the scholastic sense. This stems from his "Synechism," or the continuous coherence of all things. Expressing his fondness for John Duns Scotus, he writes: "I am myself a scholastic realist of a somewhat extreme stripe".

Peirce agrees that his semiotics is complicated, and sometimes inextricably so: "It is a nice problem to say to what class a given sign belongs". But his statistical fallibilism reassures him: "But it is seldom requisite to be very accurate; for if one does not locate the sign precisely, one will easily come near enough to its character for any ordinary purpose of logic".

Let us return to photographs. They have already been ranked as ICONS. However, this qualification is really too broad since it not only applies to traditional paintings, ideographs, diagrams, but also to algebraic equations: "an algebraic formula is an icon" ; and even to sentences: "the arranÐgement of words in the sentence must serve as Icons, in order that the sentence may be understood".

In addition, more serious problems arise when Peirce categorizes photographs among INDEXES. It is necessary to point out, in order to fully realize the stakes, that French, and Romance languages in general, differentiate between indices and indexes ö a distinction which we have tried to preserve in the English version of our text. According to this differentiation, INDICES are the effects signaling causes, thereby revealing these causes. As they are non-intentional, INDICES predominantly travel from the subject towards the object. On the other hand, INDEXES are caps which, because of their intentionality, start out from the subject towards the object. In our Philosophy of Photography, photographs can therefore be defined quite rigorously as possibly indexed indices. Indicial then refers to the natural and technical aspects of photonic imprints, while indexical refers to the side of the subject (the photographer) who chooses his frame, film, lens, developers and prints. In Logiques de dix langues europénnes, we have offered some explanations as to why English does not normally differentiate between indices and indexes, and usually only uses index (and its plural indices).

However, what is most disturbing is not the fact that, as an English speaker and a logician who should not have succumbed to this confusion, Peirce covers two divergent meanings (indices/index) with one word. Rather, what is most striking is that in the end, Peirce only acknowledges indices (in the sense we have just explained), which he then groups under the name of index wherever he finds them. As such, Peircean INDEXES, which are synonymous with our INDICES, simultaneously cover: 1) indices, such as thunder or imprints, thus also including photographs; 2) linguistic indexes such as possessive pronouns ("a possessive pronoun is in two ways an index"), as well as relative and demonstrative pronouns and quantifiers ("quilibet, quisquam, quidam"); 3) propositions: "a Dicisign necessarily represents itself to be a genuine Index, and to be nothing more", given that "every kind of proposition is either meaningless or has a real Secondness as its object" ; 4) the names of existent things once they are uttered or written: "A Replica of the word 'camel' is likewise a Rhematic Indexical Sinsing, being really affected, through the knowledge of camels, common to the speaker and auditor, by the real camel it denotes" ; 5) the uttered or written names of imaginary things: "The same thing is true of the word 'phþnix'. For although no phþnix really exists, real descriptions of the phþnix are well known to the speaker and his auditor; and thus the word is really affected by the Object denoted.".

Accordingly, two serious flaws arise when dealing with photography: 1) the notion of the Peircean INDEX (as the INDICIAL) is really too broad as it encompasses virtually every sign as seen from differing perspectives. 2) Peircean indiciality ("to be affected by") is often tenuous because it is reduced to a cerebral action, which is inadequate when considering the physicality of the photograph. This also instills a gap, because a full consideration of the tension between indices and indexes would have led Peirce to realize that the inherent logical operations in the "reading" of photographs illustrates his third inference remarkably well, i.e. the inference which he calls abduction or retroduction, in addition to deduction and induction. Finally, allowing a momentary venture outside the domain of photography, an adequate differentiation between indexes and indices would undoubtedly have prompted him to characterize Mathematics, which is one of his major concerns, as the general coordination of indexes rather than a "method of drawing necessary conclusions" or the "study of hypothetical states of things," as formulated by the doctrine of father, the mathematician Benjamin Peirce. In addition, he would also have realized that Physics is the general coordination of indices within this general coordination of indexes. However, Peircean Synechism leads one to reduce indexes to indices. Peirce himself pointed out on numerous occasions that philosophers invariable prefer coherence over the truth.

One can only wonder why so many of our contemporaries are so infatuated with the "index according to Peirce." Even here Peirce the semio-sociologist comes to our aid by underlining at length that, for reasons of academic conviviality, a vague idea and a white lie are more lucrative than clear and distinct ideas. It is the same fuzziness which, in the wake of Roland Barthes's texts, has undoubtedly been enhanced through things like the "message without code," which is a contradictio in terminis; through the ça-a-été, the having-been-there, whose "ça" or present perfect one can hardly locate precisely; through the "punctum/studium," which the majority of eminent photographers had already dismissed; through the bombast of "it is Reference, which is the founding order of Photography," even though indices 'bring' or 'bear,' from the Latin verb ferre, but do precisely not re-fer, they carry but do not point, they signal but do not designate unless they have been forged by murderers or thieves and therefore have become indexes; through the constant mixing of real and reality, which is the most convenient tool of any photographic aesthetics, while ignoring the differentiation between Reality and the Real, as well as that between World and Universe; through the phrase "the thing has been there," whereas a photograph so eloquently testifies to the fact that there are so very few "things," and only instances-states within the general flow of the Universe; through "unutterable singularities," whereas every singularity is but a possible or an illusion (of memory) as Peirce illustrated perfectly in 1868 in his seminal profession of anti-Cartesian faith entitled Some consequences of four incapacities (later, Peirce would describe the interpretant-interpreter as "a quasi-mind," "a person" and "a sop to Cerberus, because I despair of making my own broader conception understood" ).

One must understand that our reservations regarding Peirce on the specific theme of photography are amicable exigencies, since I share, implicitly but always expressly since L'Animal signé (1980), the fundamental tenet of Peirce as well as Aristotle, that, in epistemology, one should always start out with the Object in order to reach the Sign, and not inversely. Even an index, which goes from Sign to Object in a very near future, travels from Object to Sign in a distant future, as Peirce already, and rather too strongly, maintained. However, for Saussure, the contemporary of Emst Mach and the hardliner of the "arbitrariness of the sign" (following William Dwight Whitney, 1875), the Object slips into the status of a simple Referent, which one will deal with later, even if it means one can never recapture it in a truly upside-down epistemology.

Thus, if "indices" are opposed to "signs" in my Philosophy of Photography, it is only because of a nominal definition that is capable of emphasizing the sharp contrast between non-intentional photonic imprints, pictorial intentional touches and their own equally intentional indexes. This is important when keeping in mind the differentiation between 'signaling' and 'designating', as indices signal and all other signs designate. However, it goes without saying that, as my publication Fundamental Anthropology demonstrates, indices form part of the order of Signs (fever is the "sign" of an infection, and it has initiated "semiology"). Signs are even the first movements of the basic anthropogenic suite of Indices-Indexes-Paintings-Figures. However, even in this theory of photography, it would perhaps have been better had we continuously employed the language of my Fundamental Anthropology, no matter how laborious it may be and regardless of whether it would cause discomfort to some readers, as with the nominal definitions we advocated forcefully in the second chapter of this book. The well-trained scientist that he was, Peirce was too confident to be capable of believing that nominal definitions are always legitimate, and also occasionally economical.