When perception is stronger than physics: Perceptual similarities rather than laws of physics govern the perception of interacting objects

When several multistable displays are viewed simultaneously, their perception is synchronized, as they tend to be in the same perceptual state. Here, we investigated the possibility that perception may reflect embedded statistical knowledge of physical interaction between objects for specific combinations of displays and layouts. We used a novel display with two ambiguously rotating gears and an ambiguous walker-on-a-ball display. Both stimuli produce a physically congruent perception when an interaction is possible (i.e., gears counterrotate, and the ball rolls under the walker’s feet). Next, we gradually manipulated the stimuli to either introduce abrupt changes to the potential physical interaction between objects or keep it constant despite changes in the visual stimulus. We characterized the data using four different models that assumed (1) independence of perception of the stimulus, (2) dependence on the stimulus’s properties, (3) dependence on physical configuration alone, and (4) an interaction between stimulus properties and a physical configuration. We observed that for the ambiguous gears, the perception was correlated with the stimulus changes rather than with the possibility of physical interaction. The perception of walker-on-a-ball was independent of the stimulus but depended instead on whether participants responded about a relative motion of two objects (perception was biased towards physically congruent motion) or the absolute motion of the walker alone (perception was independent of the rotation of the ball). None of the two experiments supported the idea of embedded knowledge of physical interaction.

Mental imagery: pulling the plug on perceptualism

What is the relationship between perception and mental imagery? I aim to eliminate an answer that I call perceptualism about mental imagery. Strong perceptualism, defended by Bence Nanay, predictive processing theorists, and several others, claims that imagery is a kind of perceptual state. Weak perceptualism, defended by M. G. F. Martin and Matthew Soteriou, claims that mental imagery is a representation of a perceptual state, a view sometimes called The Dependency Thesis. Strong perceptualism is to be rejected since it misclassifies imagery disorders and abnormalities as perceptual disorders and abnormalities. Weak Perceptualism is to be rejected since it gets wrong the aim and accuracy conditions of a whole class of mental imagery–projected mental imagery–and relies on an impoverished concept of perceptual states, ignoring certain of their structural features. Whatever the relationship between perception and imagery, the perceptualist has it wrong.

What’s so naïve about naïve realism?

Naïve Realism claims that veridical perceptual experiences essentially consist in genuine relations between perceivers and mind-independent objects and their features. The contemporary debate in the philosophy of perception has devoted little attention to assessing one of the main motivations to endorse Naïve Realism–namely, that it is the only view which articulates our ‘intuitive’ conception of perception. In this paper, I first clarify in which sense Naïve Realism is supposed to be ‘naïve’. In this respect, I argue that it is put forward as the only view which can take our introspective knowledge of perception at face value, and I identify the two (alleged) key features of such introspective knowledge. Second, I challenge the claim that one of these features-namely, that it seems as one could not be in the same perceptual state unless the putative objects of perception existed and were perceived–is introspectively evident. Consequently, I argue that a view of perceptual experience–such as Intentionalism–which denies that this feature is true of perception can still take introspection at face value. This undermines the claim that Naïve Realism is the only account which accommodates our intuitions on the nature of perception.

Multimodal Mental Imagery and Perceptual Justification

There has been a lot of discussion about how the cognitive penetrability of perception may or may not have important implications for understanding perceptual justification. The aim of this chapter is to argue that a different set of findings in perceptual psychology poses an even more serious challenge to the very idea of perceptual justification. These findings are about the importance of perceptual processing that is not driven by corresponding sensory stimulation in the relevant sense modality (such as amodal completion and multimodal completion). These findings show that everyday perception is in fact a mixture of sensory-stimulation-driven perceptual processing and perceptual processing that is not driven by corresponding sensory stimulation in the relevant sense modality and that we have strong reasons to doubt the epistemic pedigree of the latter process. The implication of this is not that we should become skeptics or deny the possibility of perceptual justification. It is, rather, that the only way in which we can understand when and whether a perceptual state justifies beliefs is by paying close attention to empirical facts about the reliability of perceptual processing that is not driven by corresponding sensory stimulation in the relevant sense modality. In this sense (a very narrow sense) epistemology needs to be naturalized.

A Comparative Study of Bio-Inspired Odour Source Localisation Strategies from the State-Action Perspective

Locating odour sources with robots is an interesting problem with many important real-world applications. In the past years, the robotics community has adapted several bio-inspired strategies to search for odour sources in a variety of environments. This work studies and compares some of the most common strategies from a behavioural perspective with the aim of knowing: (1) how different are the behaviours exhibited by the strategies for the same perceptual state; and (2) which are the most consensual actions for each perceptual state in each environment. The first step of this analysis consists of clustering the perceptual states, and building histograms of the actions taken for each cluster. In case of (1), a histogram is made for each strategy separately, whereas for (2), a single histogram containing the actions of all strategies is produced for each cluster of states. Finally, statistical hypotheses tests are used to find the statistically significant differences between the behaviours of the strategies in each state. The data used for performing this study was gathered from a purpose-built simulator which accurately simulates the real-world phenomena of odour dispersion and air flow, whilst being sufficiently fast to be employed in learning and evolutionary robotics experiments. This paper also proposes an xml-inspired structure for the generated datasets that are used to store the perceptual information of the robots over the course of the simulations. These datasets may be used in learning experiments to estimate the quality of a candidate solution or for measuring its novelty.

Content Particularism

Chapter 3 distinguishes four ways one might account for perceptual particular. We can take an epistemic approach and understand perceptual particularity in terms of a special epistemic relation to the particulars perceived. We can take an ontological approach and understand perceptual particularity in terms of the ontological dependence of the perceptual state on the particulars perceived. We can take a psychologistic approach and understand perceptual particularity in terms of the phenomenal character of perceptual states by arguing that phenomenal character is constituted by the particulars perceived. Finally, we can take a representational approach and understand perceptual particularity in terms of features of perceptual content. The chapter argues that perceptual particularity is best accounted for in terms of perceptual content rather than in terms of epistemic, psychologistic, or ontological dependency properties.

Perceptual Particularity

Perception grounds demonstrative reference, yields singular thoughts, and fixes the reference of singular terms. Moreover, perception provides us with knowledge of particulars in our environment and justifies singular thoughts about particulars. How does perception play these cognitive and epistemic roles in our lives? I address this question by exploring the fundamental nature of perceptual experience. Chapter 1 argues that perception is constitutively a matter of employing perceptual capacities that function to discriminate and single out particulars. Due to the central role of capacities, we can call a view that endorses this thesis capacitism. Harnessing this thesis, the chapter argues that a subject’s perceptual state is brought about by being perceptually related to an external, mind-independent particular that is constituted by that particular. Thereby, the chapter provides an account of the particular elements of perception.

Intentionalism, Cognition, and Representation

This chapter continues consideration of reductive intentionalism without embracing the doctrine, framing it in the context of cognitive science. Cognition, including perception, is representation. An agent’s cognitive, perhaps perceptual, state is a relation binding the agent to a proposition by means of her mental representation. Intentionalism would explicate the phenomenal character of a perceiver's experience in terms of the content of her prevailing perceptual representation. While minimal intentionalism maintains that the phenomenal character of the perceiver's experience merely supervenes on her representation's content, maximal intentionalism would reduce character to content. For maximal intentionalism maintains that phenomenal character is simply what introspection finds. Yet, according to maximal intentionalism, introspection, when tuned to conscious perception, detects only the content of experience. Hence, the maximalist identifies phenomenal character with the content carried by perceptual representation.

What It Is Like To Perceive

Conscious perception is a distinctive mode of cognition marked by its manifestly sensuous phenomenal character. Why? An intentionalist may reply that perception is a kind of psychological state realized by an oddly contentful mental representation. A higher order theorist might alternatively answer that a perceptual state is sensuous since it is the content of a higher order cognitive state. Neither of these representationalists is right. It is not the content of any mental state that ensures perception's phenomenal character. Rather, the unique structure of a perceptual representation determines perception's sensuous side. For a perceptual representation is an extended mental representation of a peculiar sort. It is a representation in which the vehicle of reference is itself the very object to which that vehicle refers. Perceptual representation thus differs from all other forms of cognitive representation in a way that directly acquaints a perceiver with whatever real object she perceives. Perception is sensuous because it is unbrokered cognitive contact with something present. This confrontational mode of cognition owes its phenomenal character not to what it represents but rather to how it represents. What it is like to perceive is bluntly - but exactly - to represent something real that is really at hand. Conscious perception is just direct acquaintance with what's there.

In the Eye of the Beholder

According to a core tenet of contemporary philosophy, aesthetic properties are primarily represented in experiences. Obviously, however, the tenet does not apply in any straightforward manner to many items that nevertheless seem to have aesthetic properties. Examples include literary works, mathematical objects, scientific ideas, and works of conceptual art. Aesthetic properties need not be represented in perceptual experiences, but what is an experience if not a perceptual state? This paper adapts Fred Dretske’s distinction between analogue and digital representation to develop a broad conception of a kind of state that is an experience but need not be perceptual. Aesthetic properties are primarily represented in states so conceived.