Sellars Wilfrid (1912–89), American philosopher, son of Roy Wood Sellars, and one of the great systematic philosophers of the century. His most influential and representative works are ‘Empiricism and the Philosophy of Mind’ (1956) and ‘Philosophy and the Scientific Image of Man’ (1960). The Sellarsian system may be outlined as follows.
The myth of the given. Thesis (1): Classical empiricism (foundationalism) maintains that our belief in the commonsense, objective world of physical objects is ultimately justified only by the way that world presents itself in sense experience. Thesis (2): It also typically maintains that sense experience (a) is not part of that world and (b) is not a form of conceptual cognition like thinking or believing. Thesis (3): From (1) and (2a) classical empiricism concludes that our knowledge of the physical world is inferred from sense experience. Thesis (4): Since inferences derive knowledge from knowledge, sense experience itself must be a form of knowledge. Theses (1)–(4) collectively are the doctrine of the given. Each thesis taken individually is plausible. However, Sellars argues that (2b) and (4) are incompatible if, as he thinks, knowledge is a kind of conceptual cognition. Concluding that the doctrine of the given is false, he maintains that classical empiricism is a myth. The positive system. From an analysis of theoretical explanation in the physical sciences, Sellars concludes that postulating theoretical entities is justified only if theoretical laws – nomological generalizations referring to theoretical entities – are needed to explain particular observable phenomena for which explanation in terms of exceptionless observation laws is unavailable. While rejecting any classical empiricist interpretation of observation, Sellars agrees that some account of non-inferential knowledge is required to make sense of theoretical explanation thus conceived. He thinks that utterances made in direct response to sensory stimuli (observational reports) count as non-inferential knowledge when (a) they possess authority, i.e., occur in conditions ensuring that they reliably indicate some physical property (say, shape) in the environment and are accepted by the linguistic community as possessing this quality; and (b) the utterer has justified belief that they possess this authority. Sellars claims that some perceptual conditions induce ordinary people to make observation reports inconsistent with established explanatory principles of the commonsense framework. We thus might tend to report spontaneously that an object is green seen in daylight and blue seen indoors, and yet think it has not undergone any process that could change its color. Sellars sees in such conflicting tendencies vestiges of a primitive conceptual framework whose tensions have been partially resolved by introducing the concept of sense experiences. These experiences count as theoretical entities, since they are postulated to account for observational phenomena for which no exceptionless observation laws exist. This example may serve as a paradigm for a process of theoretical explanation occurring in the framework of commonsense beliefs that Sellars calls the manifest image, a process that itself is a model for his theory of the rational dynamics of conceptual change in both the manifest image and in science – the scientific image. Because the actual process of conceptual evolution in Homo sapiens may not fit this pattern of rational dynamics, Sellars treats these dynamics as occurring within certain hypothetical ideal histories (myths) of the way in which, from certain conceptually primitive beginnings, one might have come to postulate the requisite theoretical explanations.
The manifest image, like the proto-theories from which it arose, is itself subject to various tensions ultimately resolved in the scientific image. Because this latter image contains a metaphysical theory of material objects and persons that is inconsistent with that of its predecessor framework, Sellars regards the manifest image as replaced by its successor. In terms of the Peircean conception of truth that Sellars endorses, the scientific image is the only true image. In this sense Sellars is a scientific realist.
There is, however, also an important sense in which Sellars is not a scientific realist: despite discrediting classical empiricism, he thinks that the intrinsic nature of sense experience gives to conceptualization more than simply sensory stimulus yet less than the content of knowledge claims. Inspired by Kant, Sellars treats the manifest image as a Kantian phenomenal world, a world that exists as a cognitive construction which, though lacking ideal factual truth, is guided in part by intrinsic features of sense experience. This is not (analytic) phenomenalism, which Sellars rejects. Moreover, the special methodological role for sense experience has effects even within the scientific image itself.
Theories of mind, perception, and semantics. Mind: In the manifest image thoughts are private episodes endowed with intentionality. Called inner speech, they are theoretical entities whose causal and intentional properties are modeled, respectively, on inferential and semantic properties of overt speech. They are introduced within a behaviorist proto-theory, the Rylean framework, to provide a theoretical explanation for behavior normally accompanied by linguistically overt reasons.
Perception: In the manifest image sense experiences are sense impressions – states of persons modeled on two-dimensional, colored physical replicas and introduced in the theoretical language of the adverbial theory of perception to explain why it can look as if some perceptible quality is present when it is not.
Semantics: The meaning of a simple predicate p in a language L is the role played in L by p defined in terms of three sets of linguistic rules: language entry rules, intralinguistic rules, and language departure rules. This account also supports a nominalist treatment of abstract entities. Identification of a role for a token of p in L can be effected demonstratively in the speaker’s language by saying that p in L is a member of the class of predicates playing the same role as a demonstrated predicate. Thus a speaker of English might say that ‘rot’ in German plays the semantic role ‘red’ has in English. Sellars sees science and metaphysics as autonomous strands in a single web of philosophical inquiry. Sellarsianism thus presents an important alternative to the view that what is fundamentally real is determined by the logical structure of scientific language alone. Sellars also sees ordinary language as expressing a commonsense framework of beliefs constituting a kind of proto-theory with its own methods, metaphysics, and theoretical entities. Thus, he also presents an important alternative to the view that philosophy concerns not what is ultimately real, but what words like ‘real’ ultimately mean in ordinary language. See also EPISTEMOLOGY , METAPHYSICAL REALISM , ORDINARY LANGUAGE PHILOSOPH. T.V.