Semantic Criterion

I explained in section 2.1.3, and following Engel (1988a, 1996, 2012b), how cognition can be understood. Now, following Pylyshyn’s and Engel’s explanation (1994, 143-149), I will describe what Pylyshyn understands by

‘cognitive penetration’.

The classic conception of ‘cognition’ rests on two main hypotheses. First, something is considered as a cognitive phenomenon when it can be explained by a series of generalisations of the subject’s behaviour expressible in cogni-tive vocabulary, that is, by reference to mental states (states that function as reasons to explain the behaviour). According to Fodor (1983, 1987), Pylyshyn (1980, 1984), and Fodor and Pylyshyn (1981, 1988), the expla-nation of agents’ action in psychology has to suppose that subjects act in virtue of intentional states with certain content. It is because there are certain cognitive generalisations of the form if S believes that p and de-sires that q, thenS does A, that the subject’s action can be explained (see section 2.1.3). Those are what Pylyshyn (1984, 32) calls “semantic-level generalizations”. If someone drinks water from a glass, that behaviour can be explained by appeal to the subject’s internal mental states (she was thirsty, believed that there was water in the glass, desired to drink water, etc.). Cognitive explanations are predictive and can be generalised to sim-ilar situations: if someone else is in the same circumstances with the same beliefs and desires, cognitive generalisations predict that the person would accomplish the same actions. (See Engel (1994, 144-145) for the previous explanation.)

Second, these cognitive generalisations are autonomously defined, that is, they are independent from a neurophysiological or behavioural vocab-ulary. Intentionality and rational behaviour cannot be explained by using the vocabulary of biology, neurophysiology, or even in terms of stimulus-response behaviour. Cognitive generalisations need to be elucidated in terms of intentional or semantic contents of the subject’s representational states.

For instance, it is the specific content of the subject’s mental states that

causes her to drink water. (Engel 1994, 145)

Notice that Marr (1982); Fodor (1983, 2000); Fodor and Pylyshyn (1988); Pylyshyn (1984) defend a representational theory of the mind (RTM). They hold that mental representations are symbolic structures, which are semantically evaluated. Intentional states are functional or com-putational relations between symbolic representations of the content of these states and the organism.²⁷ For example, to believe that there is a table in the room is to be in a particular functional relation to a symbol (a mental representation) whose semantic value is ‘there is a table in the room’. (See Engel 1994, 30-34, 51-54, 145; Horst 2011.)

Pylyshyn distinguishes between three levels of description in visual pro-cessing — physical or biological, symbolic or syntactic (or “functional”

(Pylyshyn 1984, 32)), and semantic or representational (Pylyshyn 1984, 131) — and appears to claim that early visual processes can be explained by these three levels of description. In his view, if a phenomenon can be ex-plained at a semantic level, it is a candidate for cognitive penetrability. But, being susceptible of a semantic explanation is not sufficient to be cognitively penetrable. Pylyshyn defines cognitive penetrability as follows:

[I]f a system is cognitively penetrable then the function it computes is sensitive, in a semantically coherent way, to the organism’s goals and beliefs, that is, it can be altered in a way that bears some logical relation to what the person knows. (Pylyshyn 1999a, 343)

[T]he term cognitive penetrability refers not merely to any influence of semantic or cognitive factors on behavior but to a specific, se-mantically explicable (that is, rational or logically coherent) effect.

(Pylyshyn 1984, 134)

According to Pylyshyn, visual perception is cognitively penetrable at the late visual level. Certain regularities in perceptual experiences will not

27This thesis combines folk psychology and physicalism and contrasts, e.g., with the thesis byChurchland(1981) andChurchland(1986), an eliminativist materialism (Engel 1988a, 16-17;1994, 55-59).

be understood if we do not take into account the subject’s cognitive back-ground. Visual representational content can be semantically explained by means of the subject’s goal, thought, decision, belief, inferences, and other rational principles (Pylyshyn 1984, 132-3, 165). Changing our cognitive background affects how the objects will be represented. Pylyshyn claims:

Without doubt, the perceptual process is cognitively penetrable [...]

in the sense required by our criterion. What one sees — or, more accurately, what one sees something to be — depends on one’s beliefs in a rationally explicable way. In particular, it depends in a quite rational way on what one knows about the object one is viewing and on what one expects. (Pylyshyn(1984, 134), see alsoPylyshyn 1984, 135, 174.)

The other sort of cognitive influence that might be observed in vision refers to cognitive penetration of early vision. But, Pylyshyn claims that the early visual system is cognitively encapsulated: its functioning cannot be explained by appeal to the subject’s cognitive background.

Pylyshyn also acknowledges that the cognitive impenetrability of a sys-tem and the application of the semantic criterion is not always straightfor-ward. He presents some possible counterexamples to his definition in which the physical regularities seem to be semantically explained by means of be-liefs, intentions, and the like. But he argues that they are not genuine cases of cognitive penetration. For instance, our beliefs involuntarily influence our organism (Pylyshyn 1984, 138-145): the heart rate can be modified if someone believes an imminent threat is nearby, or the belief that someone is going to lose her job may cause certain acids to be secreted in her stomach and alter the digestive process (Pylyshyn 1984, 138, 142). Other influences over the system may be voluntary: holding our breath for a few seconds increases the heart rate (Pylyshyn 1984, 138, 142; also Fodor 1988, 190-2) or deciding to take a sip of coffee may make the motor system extend the arm to reach a cup of coffee.

Pylyshyn claims that the influence on the visual system by higher states is not enough to account for cognitive penetration. In these examples,

al-though beliefs, fears, emotions, and so on, influence the function of the di-gestive system or endocrine system, they do not instantiate the right causal connection. The heart rate alteration does not count as a case of cognitive penetration because its behaviour can be perfectly explained in terms of biological or physical factors (Pylyshyn 1984, 140-145). If the increment of heart rate by holding one’s breath required cognitive elements to be ex-plained, the heart’s function would be cognitively penetrated. About the previous examples Pylyshyn states:

[...] My point here is that to provide an explanation of the way in which what appears to be cognitive penetration occurs in such cases as this, where the function in question is given under physical-level description, we must identify a system which contains a compo-nent that responds in a principled way to events under cognitive- (or semantic-level) description, together with a cognitively impenetrable function, such as digestion itself, whose variations can be explained by biological and physical laws. (Pylyshyn 1984, 143-144)

To summarize, a system is cognitively penetrable when its behaviour can be explained in terms of cognitive generalisations and regularities. Late vision is cognitively penetrable because the content of perceptual experi-ence is explained in a rational way according to the subject’s beliefs, desires and knowledge. However, although early vision might have a semantic level of explanation, it does not require cognitive generalisations to explain its behaviour. In the following I scrutinize two objections of Pylyshyn’s defini-tion.

4.4.1.1 Objections to the Semantic Criterion

Two objections can be addressed to this criterion. The main objection is given by Pylyshyn himself: the rationality principle is difficult to apply because it only represents an idealisation. The second problem refers to Pylyshyn’s understanding of cognitive penetration in relation to perceptual content.

1. Identification of cognitive states. When a visual process is cognitively penetrated, the explanatory or semantic criterion determines that the process must be explicated by appeal to some rationality principle.

The penetrated process of the visual system must be “semantically coherent” or bear some “logical or rational relation” to the content of subject’s cognitive states (Pylyshyn 1984, 133;Pylyshyn 1999a, 343).

However, the application of a rational principle based on the subject’s mental life presents a serious problem (Pylyshyn 1984, 135-137): How do we identify the penetrating states to apply a principle of ratio-nality? Not all cognitive and emotional states are accessible to the subject: some of them are always accessible, others are not always or not accessible at all. This represents a problem for the semantic criterion because, in order to show that cognitive penetration has oc-curred in a particular case we need to specify, first, the individual’s goals, beliefs, and emotions. If they are not accessible or evident, the rationality principle cannot be clearly applied. This is the reason why Pylyshyn(1984, 136) claims that the principle of rationality only rep-resents an “idealization”. Although a rational principle is very difficult to determine, an intelligibility and minimal sense of rationality need to be considered to account for cognitive penetration (Macpherson 2012, 28).

2. Interpretation of the concept of cognitive penetration. Another prob-lem of this definition is the meaning of ‘cognitive penetration’.

Pylyshyn considers cognitive penetration as any cognitive influence on perceptual content (see section3.2.2). Cognitive influences on pro-cesses in control of perceptual content have consequences: (a) on the content of the perceptual experience (this includes cognitive penetra-tion of perceptual experience as explained in secpenetra-tion 3.2.1), and (b) on perceptual content or content-related mechanisms that affect the subject’s actions or object recognition (even though not necessarily changes in perceptual experience). Pylyshyn’s interpretation excludes

top-down influences on non-content-related mechanisms (see section 3.2.3). The cognitive effects that can affect speed, performance, relia-bility, within the early (and late) visual systems and influence periph-eral visual mechanisms such as visuo-motor processes.

To sum up, the semantic criterion faces the problem of identifying which mental states (conscious and unconscious) might be responsible for the cog-nitive penetration of the system; it represents an idealisation. The second objection involves the loci of the penetration; it only takes into account architectural and content cognitive penetration of perceptual content.

In what follows, I scrutinize another characterisation of cognitive pene-tration given by Fiona Macpherson and Susanna Siegel.