Manifest Activity presents and critically examines the model of human power, the will, our capacities for purposeful conduct, and the place of our agency in the natural world of one of the most important and traditionally under-appreciated philosophers of the 18th century: Thomas Reid. For Reid, contrary to the view of many of his predecessors, it is simply manifest that we are active with respect to our behaviours; it is manifest, he thinks, that our actions are not merely remote (...) products of forces that lie outside of our control. Reid holds, instead, that actions are all and only those events that spring from active power and he produces insightful and imaginative arguments for the claim that only a creature with a mind is capable of having active power. He believes that only human beings, and creatures 'above us', are capable of directing events towards ends, of endowing them with purpose or direction, the distinctive feature of action. However, he also holds that all events, and not merely human actions, are products of active power, power possessed either by human beings or by God. This collection of theses leads Reid to the view that human behaviour and the progress of nature are both essentially teleological. Patterns in nature are the products of laws of which God is the author; patterns in human conduct are the products of character and the laws that individuals set for themselves. Manifest Activity examines Reid's arguments for this view and the view's implications for the nature of character, motivation and the special kind of causation involved in the production of human behavior. (shrink)

This paper propounds a new reading of Berkeley's account of the activity of finite spirits. Against existing interpretations, the paper argues that Berkeley does not hold that we causally contribute to the movement of our bodies. In contrast, our volitions to move our bodies are but occasions for God to cause their movement. In answer to the question of wherein then consists our activity, the paper proposes that our activity consists in the dual powers to produce (1) (...) our volitions ? the acts of willing ? and (2) our ideas of imagination. (shrink)

How chromatin bridges are detected by the abscission checkpoint during mammalian cell division is unknown. Here, we discuss recent findings from our lab showing that the DNA topoisomerase IIα (Top2α) enzyme binds to catenated (“knotted”) DNA next to the midbody and forms abortive Top2‐DNA cleavage complexes (Top2ccs) on chromatin bridges. Top2ccs are then processed by the proteasome to promote localization of the DNA damage sensor protein Rad17 to Top2‐generated double‐strand DNA ends on DNA knots. In turn, Rad17 promotes local recruitment (...) of the MRN protein complex and downstream ATM‐Chk2‐INCENP signaling to delay abscission and prevent chromatin bridge breakage in cytokinesis. (shrink)

Recently research on imitation and its role in social cognition has been flourishing across various disciplines. After briefly reviewing these developments under the headings of behavior, subpersonal mechanisms, and functions of imitation, I advance the _shared circuits_.

These lectures are the first extensive application of Husserl's newly developed genetic phenomenology to perceptual experience & to the way in which it is connected to judgments & cognition. Students of phenomenology will find this work indispensable.

This collection of essays discusses a central feature of European philosophy: the idea of a universal active power as the ultimate world-explanation.

An important Christian philosopher contends that if human energy is channeled in the right direction, "upward and outward," spiritual energy as a motor force in the universe will outdistance technological advance. Index. Translated by Rene Hague. A Helen and Kurt Wolff Book.

When the stored representation of the meaning of a stimulus is accessed through the processing of a sensory input it is maintained in an activated state for a certain amount of time that allows for further processing. This semantic activation is generally accompanied by conscious identification, which can be demonstrated by the ability of a person to perform discriminations on the basis of the meaning of the stimulus. The idea that a sensory input can give rise to semantic activation without (...) concomitant conscious identification was the central thesis of the controversial research in subliminal perception. Recently, new claims for the existence of such phenomena have arisen from studies in dichotic listening, parafoveal vision, and visual pattern masking. Because of the fundamental role played by these types of experiments in cognitive psychology, the new assertions have raised widespread interest. (shrink)

Cognitive niche construction is the process whereby organisms create and maintain cause–effect models of their niche as guides for fitness influencing behavior. Extended mind theory claims that cognitive processes extend beyond the brain to include predictable states of the world. Active inference and predictive processing in cognitive science assume that organisms embody predictive (i.e., generative) models of the world optimized by standard cognitive functions (e.g., perception, action, learning). This paper presents an active inference formulation that views cognitive niche construction as (...) a cognitive function aimed at optimizing organisms' generative models. We call that process of optimization extended active inference. (shrink)

Do plants represent according to Kant? This is closely connected to the question of whether he held plants are alive, because he explains life in terms of the faculty to act on one’s own representations. He also explains life as having an immaterial principle of self-motion, and as a body’s interaction with a supersensible soul. I argue that because of the way plants move themselves, Kant is committed to their being alive, to their having a supersensible ground of their self- (...) class='Hi'>activity, and to their having desires (although these are not conscious). This has important ramifications for Kant’s teleology and philosophy of mind. (shrink)

Combining active externalism in the form of the extended and distributed cognition hypotheses with virtue reliabilism can provide the long sought after link between mainstream epistemology and philosophy of science. Specifically, by reading virtue reliabilism along the lines suggested by the hypothesis of extended cognition, we can account for scientific knowledge produced on the basis of both hardware and software scientific artifacts. Additionally, by bringing the distributed cognition hypothesis within the picture, we can introduce the notion of epistemic group agents, (...) in order to further account for collective knowledge produced on the basis of scientific research teams. (shrink)

Internalist approaches to epistemic justification are, though controversial, considered a live option in contemporary epistemology. Accordingly, if ‘active’ externalist approaches in the philosophy of mind—e.g. the extended cognition and extended mind theses—are _in principle_ incompatible with internalist approaches to justification in epistemology, then this will be an epistemological strike against, at least the _prima facie_ appeal of, active externalism. It is shown here however that, contrary to pretheoretical intuitions, neither the extended cognition _nor_ the extended mind theses are in principle (...) incompatible with two prominent versions of epistemic internalism—viz., accessibilism and mentalism. In fact, one possible diagnosis is that pretheoretical intuitions regarding the incompatibility of active externalism with epistemic internalism are symptomatic of a tacit yet incorrect identification of epistemic internalism with epistemic individualism. Thus, active externalism is not in principle incompatible with epistemic internalism per se and does not significantly restrict one’s options in epistemology. (shrink)

본 논문의 목적은 삶의 공유에 대한 아리스토텔레스 이론의 도움을 받아 온라인에서의 친구들이 삶을 공유하는 것은 불가능함을 밝히는 것이다. 우선 아리스토텔레스가 왜 삶의 공유가 친구의 존재 목적에 가장 잘 부합하는 친구 사랑의 토대라고 말하고 있는지에 대해서 살펴본다. 이때 필자는 아리스토텔레스가 말하는 삶의 공유에는 바람직한 목적과 도덕적 책무의 공유가 함의되어 있음을 주목한다. 다음으로 소셜미디어를 통한 활동의 공유도 아리스토텔레스가 말하는 삶의 공유로 볼 수 있다고 생각하는 엘더의 논증들을 비판적으로 검토한다. 엘더는 소셜미디어를 통해서 말과 생각을 공유하거나 가치 있는 활동을 공유하는 것, 그리고 비언어적 수단을 (...) 통해 경험을 공유하거나 온라인에서 게임을 하는 것이 모두 삶을 공유하는 방식일 수 있다고 주장하고 있다. 마지막으로 온라인에서의 사악한 활동의 문제를 아리스토텔레스의 시각에서 윤리학적으로 진단한다. 소셜미디어가 인간의 고유한 활동에 미치는 긍정적인 요소를 부인하기란 어려운 일이다. 하지만 온라인에서의 활동 공유가 친구의 존재 목적에 가장 잘 부합하는 친구 사랑의 토대로서 기능하기를 기대하기란 더욱 어렵다는 것이 필자의 결론이다. (shrink)

According to Leontiev’s “activity approach,” the external world is not something available to be “worked over” according to a subject’s inner or “ideal” representations; at stake instead is the emergence of an “idealized” objective world that relates to a subject’s activity both internally and externally construed. In keeping with a Marxian account of anthropogenesis, Leontiev links the emergence of “ideality” with social activity itself, incorporating it within the general movement between the poles of ‘inner’ cognition and ‘external’ (...) action. In this manner, Leontiev both parallels and goes beyond Hutto and Myin’s recent “enactivist” account of “content-involving” cognition, where representational thought depends on socio-cultural scaffolding and, as such, is uniquely human. What traditionally comes to be called representational content is for Leontiev the result of the transition from a primitive cognitive apparatus of “image-consciousness” to a one which is mediated by social activity. For the being endowed with “activity-consciousness,” mental content is something apprehended by assimilating “the objective world in its ideal form” [Leontiev, 1977, p. 189]. And the precondition for such assimilation is the apprehension of meanings from their origin in the social-material system of activity. The genesis of content-involving cognition is thus coeval with the development of socializing activity systems, replete with the external representations of values and norms as described in enactivist literature as publicly scaffolded symbol systems. Leontiev thus offers an anti-internalist account of cognition commensurate with Hutto and Myin but with the added dimension of a developmental scale of analysis with which to explain the origin of human-specific cognition. (shrink)

Active, constructive, and interactive are terms that are commonly used in the cognitive and learning sciences. They describe activities that can be undertaken by learners. However, the literature is actually not explicit about how these terms can be defined; whether they are distinct; and whether they refer to overt manifestations, learning processes, or learning outcomes. Thus, a framework is provided here that offers a way to differentiate active, constructive, and interactive in terms of observable overt activities and underlying learning processes. (...) The framework generates a testable hypothesis for learning: that interactive activities are most likely to be better than constructive activities, which in turn might be better than active activities, which are better than being passive. Studies from the literature are cited to provide evidence in support of this hypothesis. Moreover, postulating underlying learning processes allows us to interpret evidence in the literature more accurately. Specifying distinct overt activities for active, constructive, and interactive also offers suggestions for how learning activities can be coded and how each kind of activity might be elicited. (shrink)

I present a view of activity, taking it that an agent is engaged in activity so long as an action of hers is occurring. I suggest that this view (a) helps in understanding what goes wrong in an argument in Thompson (2008) known sometimes as the ‘initial segment argument’, and (b) enables us to see that there could be an intelligible conception of what is basic when agents' knowledge is allowed into an account of that.

Understanding “what something is” has long occupied philosophers, and no Western thinker has had more influence on the nature of being than Aristotle. Focusing on a reinterpretation of the concept of energeia as “activity,” Aryeh Kosman reexamines Aristotle’s ontology and some of our most basic assumptions about the great philosopher’s thought.

There are 4 main arguments for euthanasia: (1) arguments appealing to consistency (e.g., from passive to active euthanasia); (2) the argument from respect for autonomy; (3) appeals to justice; and (4) the argument from interests (mercy or relief of suffering). I will argue that only the last is directly relevant to active euthanasia as a medical intervention, though arguments together from autonomy and justice can in practice (through the backdoor) provide a ground for voluntary active medical euthanasia (AME).

Beginning in earnest in the late 1990s, educational researchers devoted increasing attention to the study of “active learning,” leading to a robust literature on the topic in the scholarship of teaching and learning. Meanwhile, during largely the same period, political theorists discovered the radical philosophy of Giorgio Agamben, which soon after began to ripple through more radical forms of philosophy of education. While both the SoTL works on active learning and writings of “Agambenian” philosophers of education have offered new insights (...) into their respective fields, active learning has not yet received a systematic philosophical reflection and the community of Agambenian philosophy of education has not yet been systematized. This article addresses both gaps, first through an outline of existing Agambenian approaches to the philosophy of education and second by theorizing active learning as a form of “destituent potential.” The systematic reflection on the three threads of Agambenian philosophy of education—whatever, potentiality, and study—offers an introduction to less familiar readers, and the second section offers a model for how philosophical concepts can become theoretical tools for SoTL analysis. (shrink)

We distinguish between three philosophical views on the neuroscience of predictive models: predictive coding, predictive processing and predictive engagement. We examine the concept of active inference under each model and then ask how this concept informs discussions of social cognition. In this context we consider Frith and Friston’s proposal for a neural hermeneutics, and we explore the alternative model of enactivist hermeneutics.

In a seminal 1977 article, Rumelhart argued that perception required the simultaneous use of multiple sources of information, allowing perceivers to optimally interpret sensory information at many levels of representation in real time as information arrives. Building on Rumelhart's arguments, we present the Interactive Activation hypothesis—the idea that the mechanism used in perception and comprehension to achieve these feats exploits an interactive activation process implemented through the bidirectional propagation of activation among simple processing units. We then examine the interactive activation (...) model of letter and word perception and the TRACE model of speech perception, as early attempts to explore this hypothesis, and review the experimental evidence relevant to their assumptions and predictions. We consider how well these models address the computational challenge posed by the problem of perception, and we consider how consistent they are with evidence from behavioral experiments. We examine empirical and theoretical controversies surrounding the idea of interactive processing, including a controversy that swirls around the relationship between interactive computation and optimal Bayesian inference. Some of the implementation details of early versions of interactive activation models caused deviation from optimality and from aspects of human performance data. More recent versions of these models, however, overcome these deficiencies. Among these is a model called the multinomial interactive activation model, which explicitly links interactive activation and Bayesian computations. We also review evidence from neurophysiological and neuroimaging studies supporting the view that interactive processing is a characteristic of the perceptual processing machinery in the brain. In sum, we argue that a computational analysis, as well as behavioral and neuroscience evidence, all support the Interactive Activation hypothesis. The evidence suggests that contemporary versions of models based on the idea of interactive activation continue to provide a basis for efforts to achieve a fuller understanding of the process of perception. (shrink)

Discussions over whether these natural kinds exist, what is the nature of their existence, and whether natural kinds are themselves natural kinds aim to not only characterize the kinds of things that exist in the world, but also what can knowledge of these categories provide. Although philosophically critical, much of the past discussions of natural kinds have often answered these questions in a way that is unresponsive to, or has actively avoided, discussions of the empirical use of natural kinds and (...) what I dub “activities of natural kinding” and “natural kinding practices”. The natural kinds of a particular discipline are those entities, events, mechanisms, processes, relationships, and concepts that delimit investigation within it—but we might reasonably ask: How are these natural kinds discovered?, How are they made?, Are they revisable?, and Where do they come from? A turn to natural kinding practices reveals a new set of questions open for investigation: How do natural kinds explain through practice?, What are natural kinding practices and classifications and why should we care?, What is the nature of natural kinds viewed as a set of activities?, and How do practice approaches to natural kinds shape and reconfigure scientific disciplines? Natural kinds have traditionally been discussed in terms of how they classify the contents of the world. The metaphysical project has been one which identifies essences, laws, sameness relations, fundamental properties, and clusters of family resemblances and how these map out the ontological space of the world. But actually how this is done has been less important in the discussion than the resultant categories that are produced. I aim to rectify these omissions and suggest a new metaphysical project investigating kinds in practice. (shrink)

Using an explicit task cuing paradigm, we tested whether masked cues can trigger task-set activation, which would suggest that unconsciously presented stimuli can impact cognitive control processes. Based on a critical assessment of previous findings on the priming of task-set activation, we present two experiments with a new method to approach this subject. Instead of using a prime, we varied the visibility of the cue. These cues either directly signaled particular tasks in Experiment 1, or certain task transitions in Experiment (...) 2. While both masked task and transition cues affected task choice, only task cues affected the speed of task performance. This observation suggests that task-specific stimulus–response rules can be activated only by masked cues that are uniquely associated with a particular task. Taken together, these results demonstrate that unconsciously presented stimuli have the power to activate corresponding task sets. (shrink)

Spontaneous activity levels prior to stimulus presentation can determine how that stimulus will be perceived. It has also been proposed that such spontaneous activity, particularly in the default-mode network (DMN), is involved in self-related processing. We therefore hypothesised that pre-stimulus activity levels in the DMN predict whether a stimulus is judged as self-related or not. Method: Participants were presented in the MRI scanner with a white noise stimulus that they were instructed contained their name or another. They (...) then had to respond with which name they thought they heard. Regions where there was an activity level difference between self and other response trials two seconds prior to the stimulus being presented were identified. Results: Pre-stimulus activity levels were higher in the right temporoparietal junction (RTPJ), the right temporal pole (RTP), and the left superior temporal gyrus in trials where the participant responded that they heard their own name than trials where they responded that they heard another. Conclusion: Pre-stimulus spontaneous activity levels in particular brain regions, largely overlapping with the DMN, predict the subsequent judgement of stimuli as self-related. This extends our current knowledge of self-related processing and its apparent relationship with intrinsic brain activity in what can be termed a rest-self overlap. (shrink)

Newton published his deduction of universal gravity in Principia (first ed., 1687). To establish the universality (the particle-to-particle nature) of gravity, Newton must establish the additivity of mass. I call ‘additivity’ the property a body's quantity of matter has just in case, if gravitational force is proportional to that quantity, the force can be taken to be the sum of forces proportional to each particle's quantity of matter. Newton's argument for additivity is obscure. I analyze and assess manuscript versions of (...) Newton's initial argument within his initial deduction, dating from early 1685. Newton's strategy depends on distinguishing two quantities of matter, which I call ‘active’ and ‘passive’, by how they are measured. These measurement procedures frame conditions on the additivity of each quantity so measured. While Newton has direct evidence for the additivity of passive quantity of matter, he does not for that of the active quantity. Instead, he tries to infer the latter from the former via conceptual analyses of the third law of motion grounded largely on analogies to magnetic attractions. The conditions needed to establish passive additivity frustrate Newton's attempted inference to active additivity. (shrink)

Actively open-minded thinking is often used as a proxy for reflective thinking in research on reasoning and related fields. It is associated with less biased reasoning in many types of tasks. However, few studies have examined its psychometric properties and criterion validity. We developed a shortened, 17-item version of the AOT for quicker administration. AOT17 is highly correlated with the original 41-item scale and has highly similar relationships to other thinking dispositions, social competence and supernatural beliefs. Our analyses revealed that (...) the AOT is not a unitary construct, but comprises four distinct dimensions, some of which concern attitudes towards knowledge, and others concern attitudes towards people. This factor structure was replicated in another data-set, and correlations with other measures in four data-sets support the criterion validity of these dimensions. Different dimensions were responsible for the AOT's relationships with other thinking dispositions. (shrink)

In this volume, Engeström's work is used as a springboard to reflect on the question of the use, appropriation, and further development of the classic heritage within activity theory.

Watching, looking at, and listening to, are all things that perceiving agents actively do. Though the occurrence of these activities appears to entail perception of elements of the agent's environment, perception is not something that can be actively done by agents. This raises the question how perceptual activity and perception are related to one another. This chapter, through reflecting on a discussion of listening offered by Brian O'Shaughnessy, argues that listening to material particulars ought to be understood as the (...) agential maintenance of aural awareness of those particulars, with the aim of knowing what sounds they are making. He goes on to explore some of the consequences of these claims about listening for exercises of perceptual agency involving the other sensory modalities. (shrink)

We present and contrast two accounts of cooperative communication, both based on Active Inference, a framework that unifies biological and cognitive processes. The mental alignment account, defended in Vasil et al., takes the function of cooperative communication to be the alignment of the interlocutor's mental states, and cooperative communicative behavior to be driven by an evolutionarily selected adaptive prior belief favoring the selection of action policies that promote such an alignment. We argue that the mental alignment account should be rejected (...) because it neglects the action-oriented nature of cooperative communication, which skews its view of the dynamics of communicative interaction. We introduce our own conception of cooperative communication, inspired by a more radical ecological interpretation of the active inference framework. Cooperative communication, on our ecological conception, serves to guide and constrain the dynamics of the cooperative interaction via the construction and restructuring of shared fields of affordances, in order to reach the local goals of the joint actions in which episodes of cooperative communication are embedded. We argue that our ecological conception provides a better theoretical standpoint to account for the action-oriented nature of cooperative communication in the active inference framework. (shrink)

Kant argued that the perceptual representations of space and time were templates for the perceived spatiotemporal ordering of objects, and common to all modalities. His idea is that these perceptual representations were specific to no modality, but prior to all—they are pre-modal, so to speak. In this paper, it is argued that active perception—purposeful interactive exploration of the environment by the senses—demands premodal representations of time and space.

The influence of Kurt Goldstein on the thinking of Georges Canguilhem extended throughout his entire work. This paper seeks to examine this relationship in order to conduct a study of the norm as a nexus or connection between the concept and life. Consequently, this work will be a reflection on the approach to life as a normative activity and self-realization. For this, it will be necessary to redefine the concepts of health and disease, and make a crossover between the (...) two. At the end of this trajectory, it will be found that these concepts can explain the identity between the concept and life, which leads to the unexpected conclusion that the cure is ultimately self-healing. (shrink)

This article deals with mechanisms conceived as composed of entities and activities. In response to many perplexities about the nature of activities, a number of arguments are developed concerning their epistemic and ontological status. Some questions concerning the relations between cause and causal explanation and mechanisms are also addressed.

This paper deals with the question of agency and intentionality in the context of the free-energy principle. The free-energy principle is a system-theoretic framework for understanding living self-organizing systems and how they relate to their environments. I will first sketch the main philosophical positions in the literature: a rationalist Helmholtzian interpretation (Hohwy 2013; Clark 2013), a cybernetic interpretation (Seth 2015b) and the enactive affordance-based interpretation (Bruineberg and Rietveld 2014; Bruineberg et al. 2016) and will then show how agency and intentionality (...) are construed differently on these different philosophical interpretations. I will then argue that a purely Helmholtzian is limited, in that it can account only account for agency in the context of perceptual inference. The cybernetic account cannot give a full account of action, since purposiveness is accounted for only to the extent that it pertains to the control of homeostatic essential variables. I will then argue that the enactive affordance-based account attempts to provide broader account of purposive action without presupposing goals and intentions coming from outside of the theory. In the second part of the paper, I will discuss how each of these three interpretations conceives of the sense agency and intentionality in different ways. (shrink)

Active inference offers a unified theory of perception, learning, and decision-making at computational and neural levels of description. In this article, we address the worry that active inference may be in tension with the belief–desire–intention model within folk psychology because it does not include terms for desires at the mathematical level of description. To resolve this concern, we first provide a brief review of the historical progression from predictive coding to active inference, enabling us to distinguish between active inference formulations (...) of motor control and active inference formulations of decision processes. We then show that, despite a superficial tension when viewed at the mathematical level of description, the active inference formalism contains terms that are readily identifiable as encoding both the objects of desire and the strength of desire at the psychological level of description. We demonstrate this with simple simulations of an active inference agent motivated to leave a dark room for different reasons. Despite their consistency, we further show how active inference may increase the granularity of folk-psychological descriptions by highlighting distinctions between drives to seek information versus reward—and how it may also offer more precise, quantitative folk-psychological predictions. Finally, we consider how the implicitly conative components of active inference may have partial analogues in other systems describable by the broader free energy principle to which it conforms. (shrink)

Skilled activity, such as shaving or dancing, differs in important ways from many of the stock examples that are employed by action theorists. Some critics of the causal theory of action contend that such a view founders on the problem of skilled activity. This paper examines how a causal theory can be extended to the case of skilled activity and defends the account from its critics.

Many philosophers maintain that there is a distinction between acts that the agent plays an active role in producing, and acts that issue from the agent in a more passive fashion. According to the standard account, we can make sense of this distinction by maintaining that reflective or deliberative acts are paradigmatic cases of an agent’s playing an active role in the production of action. This chapter argues that this standard account is mistaken. Reflective or deliberative actions will seem to (...) be active only if we conflate three claims: that choice causes action, that motives do not determine choice, and that reflection suspends the effects of motives. The chapter argues that while and are true, is false. Further, is needed to support the claim that reflective acts are active. Given the falsity of, the chapter shows that reflective acts are not necessarily more active than unreflective ones. The chapter closes by suggesting a new model of agential activity. (shrink)

While action selection strategies in well‐defined domains have received considerable attention, little is yet known about how people choose what to do next in ill‐defined tasks. In this contribution, we shed light on this issue by considering everyday tasks, which in many cases have a multitude of possible solutions (e.g., it does not matter in which order the items are brought to the table when setting a table) and are thus categorized as ill‐defined problems. Even if there are no hard (...) constraints on the ordering of subtasks in everyday activities, our research shows that people exhibit specific preferences. We propose that these preferences arise from bounded rationality, that is, people only have limited knowledge and processing power available, which results in a preference to minimize the overall physical and cognitive effort. In the context of everyday activities, this can be achieved by (a) taking properties of the spatial environment into account to use them to one's advantage, and (b) employing a stepwise‐optimal action selection strategy. We present the Opportunistic Planning Model as an explanatory cognitive model, which instantiates these assumptions, and show that the model is able to generalize to new everyday tasks, outperforming machine learning models such as neural networks during generalization. (shrink)

Accounts of ontic explanation have often been devised so as to provide an understanding of mechanism and of causation. Ontic accounts differ quite radically in their ontologies, and one of the latest additions to this tradition proposed by Peter Machamer, Lindley Darden and Carl Craver reintroduces the concept of activity. In this paper I ask whether this influential and activity-based account of mechanisms is viable as an ontic account. I focus on polygenic scenarios—scenarios in which the causal truths (...) depend on more than one cause. The importance of polygenic causation was noticed early on by Mill (1893). It has since been shown to be a problem for both causal-law approaches to causation (Cartwright 1983) and accounts of causation cast in terms of capacities (Dupré 1993; Glennan 1997, pp. 605-626). However, whereas mechanistic accounts seem to be attractive precisely because they promise to handle complicated causal scenarios, polygenic causation needs to be examined more thoroughly in the emerging literature on activity-based mechanisms. The activity-based account proposed in Machamer et al. (2000, pp. 1-25) is problematic as an ontic account, I will argue. It seems necessary to ask, of any ontic account, how well it performs in causal situations where—at the explanandum level of mechanism—no activity occurs. In addition, it should be asked how well the activity-based account performs in situations where there are too few activities around to match the polygenic causal origin of the explanandum. The first situation presents an explanandum-problem and the second situation presents an explanans-problem—I will argue—both of which threaten activity-based frameworks. (shrink)