The commentaries collectively provide a thoughtful and constructive analysis of resource-rational contractualism (RRC), helping both to push the theory forward and clarifying its limitations. We use these as a springboard to revise and improve upon the ideas presented in the target article. Our replies are organized in three main themes: possible extensions, challenges, and wider applications.

We discuss the functions and evolution of conscious vision. Conscious vision, we argue, operates too slowly to be suited for immediate actions, but instead evolved for offline cognition. We trace the emergence of conscious vision to the water-to-land transition, where larger terrestrial sensory horizons allowed animals to benefit from model-based planning. This shift drove the evolution of “reality monitoring” – the capacity to determine whether internal signals reflect external reality or endogenous activity uncoupled from sensory input. Following higher-order theories of consciousness, we associate consciousness with this reality monitoring function and discuss novel empirical predictions.

Fleming and Michel argue that consciousness lags up to 450 ms behind the world. I argue that the “aquatic sensory volume” for objects ecologically relevant for fish lies outside this window. If “reality monitoring” is an important function of consciousness, it likely evolved well before the transition to land in the vertebrate lineage.

The postdictive experimental paradigm is not superior to the direct detection paradigm, according to which the best strategy to identify the neural correlate of visual consciousness is to treat postdiction as a confounding factor. We could at most establish an equal claim to legitimacy of the two paradigms; hence, there is no puzzle about the function of a “slow” consciousness.

We challenge Fleming and Michel’s claim that conscious vision is too slow for real-time action. Correlative and functional evidence suggest that conscious perception can emerge around 200 ms post-stimulus and guide behavior. Due to their reliance on rare postdiction effects and assumptions about unconscious vision, they underestimate the speed of conscious vision and overestimate the functional relevance of unconscious vision.

A strict lower limit of 400 ms is suggested for the formation of conscious vision. This processing delay could result from the need to create a unified percept over visual features processed with different time constants, and even longer intentional visual processes. Given the flexibility of these processing times, we question the need for a strict lower limit for conscious vision.

In a vision-first story, conscious vision evolved before other kinds of conscious experience. This can be contrasted with an olfaction-first story, in which conscious vision co-opted integrative mechanisms that first evolved for modeling the causes of olfactory stimuli. An olfaction-first story makes good sense of the connection between consciousness and holistic integration across temporal windows in the ∼400ms range.

The authors make common assumptions that I reject: that consciousness has functions distinct from those of the brain processes on which it depends, that there is a moment at which consciousness happens, and that consciousness itself can be measured. This leads to Cartesian materialism and asking such unanswerable questions as when and why consciousness evolved. An alternative view is proposed.

The target article maintains that consciousness emerged only when slow perceptual processing would be useful. But the formation of a conscious percept could be fast even if the vulcanization of that percept is slow. And fast formation may be too fast for a higher-order pointer to form.

Fleming and Michel propose that conscious vision evolved as a result of the water-to-land transition of animal life, enabling what they call “reality monitoring.” Here, we challenge their account by drawing on evolutionary arguments and the sensory capacities of aquatic life. Consciousness, we suggest, may have deeper evolutionary roots with significant roles for “slow” decision-making.

This comment critiques the concept of “sensory horizon” for focussing narrowly on vision, overlooking aquatic animals’ rich multisensory integration. Aquatic vertebrates possess sophisticated auditory, mechanosensory, olfactory, and tactile systems that support essential behaviours. Evidence indicates that multisensory integration evolved in water, challenging visual-centric views. We thus urge replacing “sensory horizon” with “multisensory horizon” to more accurately reflect ecological and evolutionary realities.

Fleming and Michel’s hypothesis about the origins of consciousness not only faces multiple challenges but also overlooks phenomenal experience—the very phenomenon that needs explaining. Although we are in broad agreement with the authors’ overall perspective, we highlight challenges and suggest that consciousness evolved to attribute subjective value, enabling organisms to care about and act upon what they sense.

Fleming and Michel propose that conscious vision supports model-based planning, which they link to the water-to-land transition. However, the water-to-land transition may have impacted vision more than other sensory modalities. I argue that for human olfaction, which is tuned to implicit processing and high emotional salience, consciousness might often be considered as an add-on more than a necessity.

Fleming and Michel convincingly argue that the water-to-land transition put evolutionary pressure on the temporal structure of conscious vision. But their interpretation of postdictive effects, which leads them to conclude that conscious vision is slow, suffers from conceptual issues and inadvertently leads them to an overly discrete and serial model of temporal consciousness.

We argue that evolutionarily conserved processing of visual information via subcortical routes persists in humans despite the emergence of cortical networks for conscious visual perception and the rapid visual control of planned actions. These cortical circuits did not replace subcortical circuits but instead evolved the capacity to preset the nested subcortical circuits to enable (or suppress) fast-as-possible actions, when required.

Fleming and Michel associate consciousness with sensory horizons, model-based computations, reality monitoring, and decision termination. However, these functions can be implemented without consciousness and may make consciousness epiphenomenal. As with other current theories of consciousness, too much explanatory weight rests on a small number of explanatory factors.

We challenge Fleming and Michel’s arguments that aquatic animals do not have conscious vision. Focusing on fish, we suggest – on the basis of what we know about their cognition and evolution – that most fish are likely to have conscious vision, which evolved well before the transition to a largely terrestrial habitat. We end by clarifying the difference between our model-based, learning-driven view of the evolution of animal consciousness and Fleming and Michel’s view.

Arthropods, such as jumping spiders, depend on vision over a distance when hunting. Their tactics suggest planning. Experimental evidence indicates that they use representations acquired from one location when acting in another. These tiny creatures should, therefore, depend upon reality-monitoring and be conscious. Is this necessarily the case? Could we know what sort of consciousness they might possess?

The sensory horizons hypothesis as an explanation of consciousness depends on visual experience directly affecting neural activity underlying conscious model-based planning. Given that there is no known mechanism for subjective experience to generate action potentials, the sensory horizons hypothesis lacks explanatory insight into the function of consciousness. We contend that a better strategy is to investigate non-causal functions of consciousness.

Fleming & Michel (F&M) argue that the function of perceptual consciousness is to aid unconscious model-based planning. Unfortunately, unconscious model-based planning probably does not exist. F&M therefore face a dilemma: either perceptual consciousness is for conscious model-based planning or it is for something else. We argue that it is for something else.