Open peer commentary on the article “Constructing Constructivism” by Hugh Gash. Upshot: Gash’s retrospective analysis suggests a number of different roles for RC over the past thirty years. We outline three of these roles and then conduct a thought experiment to argue that while RC itself could be seen as a living theory that accommodates new ideas, its strongest contributions remain when it stays true to its roots and serves as a milestone along the path of educational paradigm shifts.

This paper presents a critical analysis of Tamar Szabó Gendler’s view of thought experiments, with the aim of developing further a constructivist epistemology of thought experiments in science. While the execution of a thought experiment cannot be reduced to standard forms of inductive and deductive inference, in the process of working though a thought experiment, a logical argument does emerge and take shape. Taking Gendler’s work as a point of departure, I argue that performing a thought experiment involves a process of self-interrogation, in which we are compelled to reflect on our pre-existing knowledge of the world. In doing so, we are forced to make judgments about what assumptions we see as relevant and how they apply to an imaginary scenario. This brings to light the extent to which certain forms of skill, beyond the ability to make valid logical inferences, are necessary to execute a thought experiment well.

Key words: thought experiments, gendler, cognitive skill, constructivism, science, imaginary scenarios.

The ‘Mind-Upload’ hypothesis (MU), a radical version of the Brainin-a-Vat thought experiment, asserts that a whole mind can safely be transferred from a brain to a digital device, after being exactly encoded into substrate independent informational patterns. Prima facie, MU seems the philosophical archenemy of the Embodied Mind theory (EM), which understands embodiment as a necessary and constitutive condition for the existence of a mind and its functions. In truth, whether and why MU and EM are ultimately incompatible is unobvious. This paper, which aims to answer both questions, will not simply confirm that MU and EM actually are incompatible. It will also show the true reason of their incompatibility: while EM implies that a mind’s individual identity is contingent upon the details of its physical constituents, MU presupposes that minds can be relocated from one material vessel to another. A systematic comparison between these conflicting assumptions reveals that the real shortcoming of MU is not the one usually discussed by the philosophical literature: it has nothing to do with MU’s functionalist or computationalist prerequisites, and is only secondarily related to the artificial implementability of consciousness; the real problem is that MU presupposes that minds could still be individuated and numerically identified while being reduced to immaterial formal patterns. EM seems committed to refute this assumption, but does it have sufficient resources to succeed?

Key words: mind upload, embodied cognition, embodied mind theory, enactivism, extended mind theory, brain-in-a-vat hypothesis, multiple realizability principle, singularity, functionalism, computational theory of mind, consciousness, identity, individuality, autopoi

This chapter discusses the brain-in-a-vat thought experiment and attempts to determine what needs to be specified so that one can properly imagine a brain in a vat. Daniel Dennett notes that philosophers often fail to set up their intuition pumps properly by failing to think carefully about the requirements and implications of their imagined scenarios. His suggestion is considered here and a careful look at the brain-in-a-vat thought experiment is proposed. The chapter puts the thought experiment to new use, namely, to address the biology of consciousness and to develop some new considerations in support of the enactive approach in cognitive science. Its main argument is that the brain-in-vat thought experiment, when spelled out with the requisite detail, suggests precisely that the body is not merely causally enabling for consciousness, but also constitutive.

Key words: thought experiment, Daniel Dennett, intuition pumps, biology of consciousness, enactive approach

Open peer commentary on the article “Homeostats for the 21st Century? Simulating Ashby Simulating the Brain” by Stefano Franchi. Upshot: Franchi argues that Ashby’s homeostat can be usefully understood as a thought experiment to explore the theory that life is fundamentally heteronomous. While I share Franchi’s interpretation, I disagree that this theory of life is a promising alternative that is at odds with most of the Western philosophical tradition. On the contrary, heteronomy lies at the very core of computationalism, and this is precisely what explains its persistent failure to construct life-like agents.

There exist theories of cognition that assume the importance of self-referentiality and/or self-modification. We argue for the necessity of such considerations. We discuss basic concepts of self-reference and self-amendment, as well as their relationship to each other. Self-modification will be suggested to involve non-algorithmic mechanisms, and it will be developed as a primary concept from which self-reference derives. A biologically motivated mechanism for achieving both phenomena is outlined. Problems of computability are briefly discussed in connection with the definability and describability of self-modifying systems. Finally, the relevance of these problems to applications in semantic problems of cognition is shown. We proceed in the following way. The paper starts with an outline of the evolutionary approach to cognition, as that context where the problems of circularity and recursiveness can be raised. Next, complete and incomplete forms of self-references are discussed. The “causal” theory of self-referentiality is reviewed, and a thought experiment is presented, which points out that no computable model for complete self-reference can exist. On the other hand, constructive definitions are shown to offer a framework where “selfdefining” and self-modifying systems, if such exist in reality, can be formulated. Studying the realization problem, a general abstract model is given, and a “biological computation” mechanism that corresponds to it is outlined. The underlying phenomenon, called “shifting reading frame,” is discussed in relation to how self-referentiality can be achieved through self-modification. The applicability of the approach to the autonomous definition of semantic relations in symbol systems, that may allow for a kind of autonomous “symbol grounding,” is discussed.

Context: Non-dualism suggests a new way of utilizing language without the assumption of categorically extralinguistic objects denoted by language. Problem: What is the innovative potential, what is the special value of non-dualism for science? Is non-dualism a fruitful conceptual revision or just a philosophical thought experiment with no or little significance for science? Method: We provide a concise introduction to non-dualism’s central new proposals and an overview of the papers. Results: Fourteen contributors show how this way of thinking and speaking can be operationalized creatively, but also address some of its boundaries. Implications: Since not all of the aspects and problems highlighted for discussion in the original Call for Papers were answered satisfactorily, further research is necessary. For example, research is needed on the relationship between dualism’s distinction between object language and metalanguage on the one hand and non-dualism’s distinction between descriptions so far and descriptions from now on on the other; or on the infinite regress allegations by non-dualism against dualism. Constructivist content: Some authors show that non-dualist thinking is anti-essentialist, in a similar way as constructivist thinking. Some also show that comparable questions arise; for example, the question of whether non-dualism denies the material world (containing extralinguistic objects).

Key words: Dualism, non-dualism, constructivism, descriptions, Josef Mitterer

We argue that the minimal biological requirements for consciousness include a living body, not just neuronal processes in the skull. Our argument proceeds by reconsidering the brain-in-a-vat thought experiment. Careful examination of this thought experiment indicates that the null hypothesis is that any adequately functional “vat” would be a surrogate body, that is, that the so-called vat would be no vat at all, but rather an embodied agent in the world. Thus, what the thought experiment actually shows is that the brain and body are so deeply entangled, structurally and dynamically, that they are explanatorily inseparable. Such entanglement implies that we cannot understand consciousness by considering only the activity of neurons apart from the body, and hence we have good explanatory grounds for supposing that the minimal realizing system for consciousness includes the body and not just the brain. In this way, we put the brain-in-a-vat thought experiment to a new use, one that supports the “enactive” view that consciousness is a life-regulation process of the whole organism interacting with its environment.

In this paper, we engage in a thought experiment about how students might notate their reasoning for taking a fraction of a fraction and determining its size in relation to the whole. We situate this discussion within a radical constructivist framework for learning in order to articulate how developing systems of notation with students can contribute to their learning. In particular, we posit that developing systems of notation with students is likely to contribute to what Piaget called reflected abstractions – a retroactive thematization of one’s reasoning.