A number of distinct definitions ofsustainable agriculture have been proposed. In this paper we criticize two such definitions, primarily for conflating sustainability with other objectives such as economic viability and ecological integrity. Finally, we propose and defend a definition which avoids our objections to the other definitions.

This article sets out to describe how churches have responded and continue to respond to fast-changing urban environments in Pretoria Central and Mamelodi East, animating Henri Lefebvre’s sociological perspective of citadins or urban inhabitants. We make tentative interpretations and offer critical appreciation. Churches, which were historically separated from the city centre, now directly participate in claiming a right to the city. With necessary fluidity, churches express lived African urbanisms through informality, place-making, spatial innovation and everyday rituals. Though not exhaustive, the (...) article focuses on rituals shared among historic urban Christians and contemporary African urban Christians, namely prayer, listening to the Bible and worship. These rituals, when combined with the churches’ spatial innovation, to a certain degree contribute to place-making. (shrink)

Rice's Theorem says that every nontrivia semantic property of programs is undecidable. In this spirit we show the following: Every nontrivia absolute counting property of circuits is UP-hard with respect to polynomial-time Turing reductions. For generators [31] we show a perfect analogue of Rice's Theorem.

My aim in this article is to explore ways in which American thought influenced and transformed European understandings of nature. The framework of such an attempt is a transatlantic history of ideas. I focus on two examples, in which I turn to texts by Friedrich Nietzsche and Rudolf Otto. My argument consists of four parts.From as early as the end of the nineteenth century, Nietzsche has been read as a critic of naturalism and his philosophy of art as a defense (...) of radical subjectivity.1 While the diagnosis of a philosophy of radical subjectivity is appropriate, the purported opposition to naturalism is a fallacy. Because Nietzsche only expresses himself in aphoristic or essayistic forms, however, it is not an easy .. (shrink)

In the past decade, significant social movements emerged in South Africa, in response to specific urban challenges of injustice or exclusion. This article will interrogate the meaning of such urban social movements for theological education and the church. Departing from a firm conviction that such movements are irruptions of the poor, in the way described by Gustavo Gutierrez and others, and that movements of liberation residing with, or in a commitment to, the poor, should be the locus of our theological (...) reflection, this article suggests that there is much to be gained from the praxis of urban social movements, in disrupting, informing and shaping the praxis of both theological education and the church. I will give special consideration to Ndifuna Ukwazi and the Reclaim the City campaign in Cape Town, the Social Justice Coalition in Cape Town, and Abahlali baseMjondolo based in Durban, considering these as some of the most important and exciting examples of liberatory praxes in South Africa today. I argue that theological education and educators, and a church committed to the Jesus who came ‘to liberate the oppressed’, ignore these irruptions of the Spirit at our own peril. (shrink)

Grounded in a postcolonial, liberationist urban vision, this article lamented the theological and political paralysis of urban denialism that fails African cities and African urban populations. Considering different possible urban trajectories towards 2063 – ranging from floundering to flourishing, implosion to explosion, and apocalyptic disaster to complete rebirth – it then proposed theologies of African urban citizenship, as response. It sought to articulate a vision of citizen-driven African cities, remaking cities ‘from below’, through interconnected and intersectional urban movements. It considered (...) urban citizenship not as the decent and orderly conduct of subjects of the nation-state but as the disruptive and transformative presence and participation of citizens of God’s new city, breaking into cities across the African continent. While it bemoaned the absence of ‘Africa’s urban revolution’ from mainstream theologies and politics practised in the African context, and the insufficient attention paid to it even by the Africa 2063 manifesto, it dared to evoke hope, in spite of evidence to the contrary. This should be viewed as a conceptual contribution, fusing literature study with deep urban immersion. Contribution: Grounded in a postcolonial, liberationist urban vision, this article lamented the theological and political paralysis of urban denialism that fails African cities and African urban populations, contemplating theologies of African urban citizenship instead. (shrink)

Ivan Petrella argues that the goals of liberation theology can sometimes be better served by doing it undercover. This article reflects on responses to homelessness during Covid-19 in the City of Tshwane, describing and reflecting upon it from the perspective of a researcher-theologian as well as activist-urbanist. It employed two lenses in its reflection: Petrella’s notion of the ‘undercover liberation theologian’, as well as what is known as deliberative public administration theory, as possibly complementary approaches. It traces ways in which (...) people of faith/theologians participated in the City of Tshwane through means other than explicit theological discourse. It implies that such engagement was not less theological but perhaps more strategic, describing that task of the undercover liberation theologian as that of making space, making plans, making known and making change. Ultimately, it calls for a subversion of suspect models of theological education, suggesting that it is in losing ourselves in the messiness of public processes and multiple solidarities with the poor, that the unfree might experience freedom, and liberation theological goals might find concrete expression.Contribution: This article reflects on responses in the City of Tshwane to street homelessness during Covid-19. It unpacks the notion and role of the ‘undercover’ liberation theologian in local political processes, and how losing ourselves in public processes and multiple solidarities with the urban poor, might help gain freedom for the unfree. (shrink)

After describing the challenges, myths, exclusions and opportunities of urban regeneration, this article explores the potential interface between faith-based action and different forms of urban regeneration. Focusing on different South African cities, it considers how faith-based action could participate in regenerative urban work. Faith-based action will refer to the varied responses of churches and faith-based organisations to urban challenges and transitions. It interrogates whether faith-based action only represents many similar approaches that address urban problems superficially without mediating long-term, systemic change, (...) or whether it indeed contributes to urban transformation in the sense of radical inclusivity and socio-structural spatial justice. Finally, it considers socio-theological sources that could potentially ground urban faith-based action theologically – such as an urban spirituality, an understanding of regeneration as integral liberation and mobilising socio-spiritual capital – whilst making a distinctive contribution to the processes of socially inclusive urban regeneration. (shrink)

In this article, we are exploring a methodological approach to research on faith and religious expressions in urban Africa. We are committed to trans-disciplinary work that pursues research methods mutually liberating for researchers, co-researchers and community participants and that results in long-term benefits and strengthened agency on the part of the host communities. Our reflections in this article are based on a collaborative research project1 in two regions of Pretoria, Tshwane2 – Pretoria Central and Mamelodi East – in which we (...) explore how religious innovation and competition in and amongst churches contribute to the healing or perpetuation of urban fractures. (shrink)

In this paper we answer the following well-known open question in computable model theory. Does there exist a computable not ‮א‬₀-categorical saturated structure with a unique computable isomorphism type? Our answer is affirmative and uses a construction based on Kolmogorov complexity. With a variation of this construction, we also provide an example of an ‮א‬₁-categorical but not ‮א‬₀-categorical saturated $\Sigma _{1}^{0}$ -structure with a unique computable isomorphism type. In addition, using the construction we give an example of an ‮א‬₁-categorical but (...) not ‮א‬₁-categorical theory whose only non-computable model is the prime one. (shrink)

We answer a question of Ambos-Spies and Kuˇcera in the affirmative. They asked whether, when a real is low for Schnorr randomness, it is already low for Schnorr tests.

We will show that there is a strong form of emergence in cell biology. Beginning with C.D. Broad's classic discussion of emergence, we distinguish two conditions sufficient for emergence. Emergence in biology must be compatible with the thought that all explanations of systemic properties are mechanistic explanations and with their sufficiency. Explanations of systemic properties are always in terms of the properties of the parts within the system. Nonetheless, systemic properties can still be emergent. If the properties of the components (...) within the system cannot be predicted, even in principle, from the behavior of the system's parts within simpler wholes then there also will be systemic properties which cannot be predicted, even in principle, on basis of the behavior of these parts. We show in an explicit case study drawn from molecular cell physiology that biochemical networks display this kind of emergence, even though they deploy only mechanistic explanations. This illustrates emergence and its place in nature. (shrink)

What are we? What is the nature of the human person? Animalism has a straightforward answer to these long-standing philosophical questions: we are animals. After being ignored for a long time in philosophical discussions of our nature, this idea has recently gained considerable support in metaphysics and philosophy of mind. Containing mainly new papers as well as two highly important articles that were recently published elsewhere, this volume's contributors include both emerging voices in the debate and many of those who (...) have been instrumental in shaping it. Some of their contributions defend animalism, others criticize it, still others explore its more general implications. The book also contains a substantial introduction by the editors explaining what animalism is, identifying leading issues that merit attention, and highlighting many of the issues that the contributors have raised. (shrink)

This paper examines the theoretical background and actual behavior in a gaming tournament with endogenous timing where a person has more incentive, structure, and time to form a strategy. The baseline treatment suggests that subgame perfection is a reasonable predictor of behavior –- subjects made 170 of 208 theoretically predicted choices of best actions, with the majority of mistakes made in timing choices by the players who did not survive the cut to the second round. Four sensitivity treatments established that (...) the design feature that lead to more predictable behavior was time to think –- 745 of 960 correctly predicted decisions with more time versus 595 of 960 with less time. A random effects Probit model suggests that the key design feature that closed the gap between predicted and observed behavior was not necessarily the non-linear payoffs created by the tournament design, but rather that the key was providing people with more time to think about their strategy. (shrink)

Biological evolution provides a creative fount of complex and subtle adaptations, often surprising the scientists who discover them. However, because evolution is an algorithmic process that transcends the substrate in which it occurs, evolution’s creativity is not limited to nature. Indeed, many researchers in the field of digital evolution have observed their evolving algorithms and organisms subverting their intentions, exposing unrecognized bugs in their code, producing unexpected adaptations, or exhibiting outcomes uncannily convergent with ones in nature. Such stories routinely reveal (...) creativity by evolution in these digital worlds, but they rarely fit into the standard scientific narrative. Instead they are often treated as mere obstacles to be overcome, rather than results that warrant study in their own right. The stories themselves are traded among researchers through oral tradition, but that mode of information transmission is inefficient and prone to error and outright loss. Moreover, the fact that these stories tend to be shared only among practitioners means that many natural scientists do not realize how interesting and lifelike digital organisms are and how natural their evolution can be. To our knowledge, no collection of such anecdotes has been published before. This paper is the crowd-sourced product of researchers in the fields of artificial life and evolutionary computation who have provided first-hand accounts of such cases. It thus serves as a written, fact-checked collection of scientifically important and even entertaining stories. In doing so we also present here substantial evidence that the existence and importance of evolutionary surprises extends beyond the natural world, and may indeed be a universal property of all complex evolving systems. (shrink)

In this paper I examine an argument that has been made by Patrick Grim for the claim that de se knowledge is incompatible with the existence of an omniscient being. I claim that the success of the argument depends upon whether it is possible for someone else to know what I know in knowing (F), where (F) is a claim involving de se knowledge. I discuss one reply to this argument, proposed by Edward Wierenga, that appeals to first-person propositions and (...) argue that this response is unsuccessful. I then consider David Lewis’s theory of de se attitudes involving the self-ascription of properties. I claim that, according to this theory, there are two senses in which someone else can know what I know in knowing (F). I then argue that the second sense allows for the compatibility of de se knowledge with the existence of an omniscient being. (shrink)

To date the problem of finding a general characterization of injective enumerability of recursively enumerable (r.e) classes of r.e. sets has proved intractable. This paper investigates the problem for r.e. classes of cofinite sets. We state a suitable criterion for r.e. classesC such that there is a boundn∈ω with |ω-A|≤n for allA∈C. On the other hand an example is constructed which shows that Lachlan's condition (F) does not imply injective enumerability for r.e. classes of cofinite sets. We also look at (...) a certain embeddability property and show that it is equivalent with injective enumerability for certain classes of cofinite sets. At the end we present a reformulation of property (F). (shrink)

We present a version of system Fω, called image, in which the layer of type constructors is essentially the traditional one of Fω, whereas provability of types is classical. The proof-term calculus accounting for the classical reasoning is a variant of Barbanera and Berardi’s symmetric λ-calculus.We prove that the whole calculus is strongly normalising. For the layer of type constructors, we use Tait and Girard’s reducibility method combined with orthogonality techniques. For the layer of terms, we use Barbanera and Berardi’s (...) method based on a symmetric notion of reducibility candidate. We prove that orthogonality does not capture the fixpoint construction of symmetric candidates.We establish the consistency of image, and relate the calculus to the traditional system Fω, also when the latter is extended with axioms for classical logic. (shrink)

Two features are often assumed about emotions: they are intentional states and they are experiences. However, there are important reasons to consider some affective responses that are not experienced or only partly experienced as emotions. But the existence of these affective responses does not sit well with the intentionality of conscious emotions which are somehow geared towards their object. We therefore face a trilemma: either these latter affective responses do not have intentional objects and we should renounce intentionality as a (...) defining feature of emotions; or we have to explain how they actually have intentional, though unconscious, objects; or after all we must deny that they are really emotions. I suggest that the second option is the correct one: we can provide an account of the intentionality of unconscious emotions and its relation to the intentionality of conscious emotions. To do this, I rely on neuropsychological studies that distinguish two kinds of attention: salience as enriched treatment, and focus as a way of turning our attention. Then, given that only salience is always present in unconscious emotional phenomena, I suggest that emotions are intentional because they involve an object being made salient. I further argue that this feature of emotions explains why unconscious and conscious emotions can be taken as organized around their object. Finally, I defend this account against several objections, showing that the account can be applied whatever the cognitive base of the emotions may be and is not falsified by the fact that attentional aspects of emotions may vary in other dimensions. (shrink)

Am 14. Juli 1995 berichteten die angesehene Wissenschaftszeitschrift Science sowie die berühmte amerikanische Tageszeitung New York Times – auf dem Titelblatt – gleichzeitig über die erstmalige experimentelle Erzeugung eines Bose-Einstein-Kondensates aus einem Gas schwach wechselwirkender Alkaliatome am Joint Institute for Laboratory Astrophy- sics (JILA) in Boulder/Colorado (USA). Was war an dieser Leistung so bedeutsam, dass man sich entschloss, sie auf jene Weise bekannt zu geben?

M. Merleau-Ponty and F. H. Jacobi’s Revelation against Kantian IntellectualismThe goal of this article is to shed light on the neglected connection between Friedrich Heinrich Jacobi (1743-1819) and Maurice Merleau-Ponty (1908-1961). It will be shown through certain themes –I) being in the world, II) description, III) reflexion, IV) revelation and the V) primacy of perception – how Merleau-Ponty echoes Jacobi’s criticism of German Idealism during the Pantheist Quarrel, particularly towards Immanuel Kant’s intellectualist stance, two centuries prior to the Phénoménologie de (...) la perception. Through a historical and philological lens, this article aims to specifically demonstrate how Merleau-Ponty and Jacobi share a common ontology against Kantian intellectualism.La rivelazione di M. Merleau-Ponty e F. H. Jacobi contro l’intellettualismo kantianoL’obiettivo di questo articolo è chiarire la trascurata relazione tra Friedrich Heinrich Jacobi (1743-1819) e Maurice Merlau-Ponty (1908-1961). Attraverso l’analisi di alcune tematiche – l’essere nel mondo, la descrizione, la riflessione, la rivelazione –, mostreremo come nella filosofia di Merleau-Ponty riecheggi la critica all’idealismo tedesco formulata da Jacobi all’epoca della disputa sul panteismo e diretta, in particolar modo e con due secoli di anticipo rispetto alla Fenomenologia della Percezione, alle posizioni intellettualiste di Kant. Grazie ad una lettura storica e filologica, questo articolo tenta di dimostrare come Merleau-Ponty e Jacobi condividano un’ontologia comune in opposizione all’intellettualismo kantiano. (shrink)

M. Merleau-Ponty and F. H. Jacobi’s Revelation against Kantian IntellectualismThe goal of this article is to shed light on the neglected connection between Friedrich Heinrich Jacobi (1743-1819) and Maurice Merleau-Ponty (1908-1961). It will be shown through certain themes –I) being in the world, II) description, III) reflexion, IV) revelation and the V) primacy of perception – how Merleau-Ponty echoes Jacobi’s criticism of German Idealism during the Pantheist Quarrel, particularly towards Immanuel Kant’s intellectualist stance, two centuries prior to the Phénoménologie de (...) la perception. Through a historical and philological lens, this article aims to specifically demonstrate how Merleau-Ponty and Jacobi share a common ontology against Kantian intellectualism.La rivelazione di M. Merleau-Ponty e F. H. Jacobi contro l’intellettualismo kantianoL’obiettivo di questo articolo è chiarire la trascurata relazione tra Friedrich Heinrich Jacobi (1743-1819) e Maurice Merlau-Ponty (1908-1961). Attraverso l’analisi di alcune tematiche – l’essere nel mondo, la descrizione, la riflessione, la rivelazione –, mostreremo come nella filosofia di Merleau-Ponty riecheggi la critica all’idealismo tedesco formulata da Jacobi all’epoca della disputa sul panteismo e diretta, in particolar modo e con due secoli di anticipo rispetto alla Fenomenologia della Percezione, alle posizioni intellettualiste di Kant. Grazie ad una lettura storica e filologica, questo articolo tenta di dimostrare come Merleau-Ponty e Jacobi condividano un’ontologia comune in opposizione all’intellettualismo kantiano. (shrink)

Die im ersten Band der „Werke” Bubers unter dem Titel „Schriften zur Philosophie” herausgegebenen Publikationen behandeln vielfach Probleme der Theologie, der Mystik, der Erziehungswissenschaften, Psychologie, Psychotherapie, Soziologie und Politik. Der Verfasser fragt sich, ob dieser heterogenen Vielfalt eine gedankliche Einheit innewohnt. Wenn man grundsätzlich zwischen Religionsphilosophie und Theologie unterscheidet, wenn man ferner annimmt, dasz die Philosophie sich auf ein Feld nichtphilosophischer Erfahrungen besinnen kann, ohne darum ihren philosophischen Charakter einzubüszen, dann kann diese Frage bejaht werden. Allerdings trägt Bubers philosophische Besinnung (...) dem empirischen Charakter von Soziologie, Psychologie, Erziehungswissenschaft in keiner Weise Rechnung. - Der Verfasser trachtet an der Hand der wichtigsten „Schriften” nachzuweisen, dasz ihre Einheit aus existentiellen Eindrücken des jungen Buber erwächst : in negativer Hinsicht aus seiner Ablehnung der liberalen Gesellschaftsordnung, in positiver aus seiner begeisterten Hinwendung zu einer - im weitesten Sinne - „religiös” inspirierten Gemeinschaft. (shrink)

Dondeyne, A. Pluriformiteit en eenheid van de filosofie.--Peperzak, A. Wegwijzers naar een dialogiek?--Boer, T. de. De eindigheid van de mens en de oneindigheid van de waarheid.--Hollak, J. Wijsgerige reflecties over de scheppingsidee : St. Thomas, Hegel en de Grieken.--Plat, J. Kants kritiek op de rationele psychologie.--Melsen, A. van. Wijsgerige antropologie en de ontwikkeling van natuurwetenschap en techniek.--Buytendijk, F. Het pathisch aspect van de eindigheid.--Struyker Boudier, H. 's Bergbeklimmers einder.

Menschen können heute in der für sie gewohnten Weise leben, weil Hunderte und Tausende von Generationen Erfahrungen über die Natur gesammelt und weitergegeben haben. Wir wissen, was wir essen und trinken können und was nicht, wie wir uns kleiden, wie wir wohnen und wie wir uns verhalten. Wir haben dieses Wissen übernommen und weiter gestaltet. Menschen können in einer bedrohlichen bis feindlichen, aber wiederum auch sie ernährenden und schützenden Welt überleben, weil sie die überkommenen Erfahrungen und das Wissen weiter (...) kultiviert haben. Die kulturelle Existenzform ist eine Besonderheit und unterscheidet Menschen von anderen Lebewesen, welche sich in ihre Umwelt problemlos einfügen. (shrink)

The task of computing a function F with the help of an oracle X can be viewed as a search problem where the cost measure is the number of queries to X. We ask for the minimal number that can be achieved by a suitable choice of X and call this quantity the query complexity of F. This concept is suggested by earlier work of Beigel, Gasarch, Gill, and Owings on “Bounded query classes”. We introduce a fault tolerant version and (...) relate it with Ulam's game. For many natural classes of functions F we obtain tight upper and lower bounds on the query complexity of F. Previous results like the Nonspeedup Theorem and the Cardinality Theorem appear in a wider perspective. (shrink)

Darstellung des Noema in 12 Thesen.\nverwendete Textstellen: Ideen 1: S. 203, 22-23; S. 204, 20-21; S. 357, 19-20: Handlungen sind zielgerichtet. Dabei bedarf eines keines physischen Objekts. Husserl setzt and diese Stelle das Noema. Somit wird auch zielgerichtetes Handeln aufgrund einer Halluzination m{ö}glich, Zielgerichtet zu sein bedeutet ein Noema zu haben.\n1. Follesdal´sche These: Noema ist eine intensionale Entit{ä}t, eine Generalisierung des Begriffs Sinn/Bedeutung.\n2. These: Das Noema hat zwei Bestandteile, a) der noematische Sinn, der allen thetischen Handlungen (erinnern, sich vorstellen usw.) (...) gem{ä}{ß} desselben Objekts mit denselben Eigenschaften in derselben Gerichtetheit gemeinsam ist und b) die Gegebenheitsweise (hat auch Sinncharakter), die sich unterscheidet in Handlungen mit verschiedenem thetischen Charakter.\n3. These: Der noematische Sinn ergibt sich aus der Art und Weise, wie Bewu{ß}tsein zum Objekt in Relation steht.\n!! 4. These: Das Noema einer Handlung ist nicht das Objekt dieser Handlung\n5. These: Das Objekt einer Handlung ist eine Funktion des noematischen Sinns, d.h. mit einem bestimmten Noema kann nur ein Objekt korrespondieren.\n6. These: Jedoch k{ö}nnen mit einem bestimmten Objekt verschiedene Noemata korrespondieren. (z.B. kann ein Objekt das Ziel verschiedener thetischer Handlunge sein, etwa erinnern, wahrnehmen, daher:)\n6. These a): Mit einem bestimmten Objekt korrespondieren verschiedene noematische Sinne.\n7. These: Jede Handlung besteht aus nur einem Noema. Sie wird durch dieses Noema charakterisiert. (Umgekehrt trifft dies nicht zu.)\n8. These: Noemata sind abstrakte Entit{ä}ten. (Sinne sind nicht real. Sie sind bezogen auf Handlungen in tempor{ä}ren Intervallen.)\n9. These: Noemata werden nicht durch unsere Sinnesorgane wahrgenommen.\n10. These: Noemata gelangen durch ph{ä}nomenologische Reflektion ins Bewu{ß}tsein.\n11. These: Eine ph{ä}nomenologische Reflektion kann iterativ geschehen (ann{ä}herungsweise; in Schritte gegliedert). Dies ist so, weil schon die Korrespondenz zwischen Sinn und Objekt wieder ein Objekt ergibt. Es folgt ein unendlicher Regress.\nPhysische Objekte sind transzendent in dem Sinne, dass sie unendlich viele Noemata haben. Sinn kann sie nie ersch{ö}pfend erfassen.\nNoemata k{ö}nnen andererseits ein physisches Objekt repr{ä}sentieren in der Form, dass mehr intendiert wird als gesehen wird. So denkt man sich etwa bei einem Stuhl, von dem man nur zwei Beine sieht, die beiden {ü}brigen hinzu.\n12. These: Diese Muster der Vorherbestimmung bilden zusammen mit den Gegebenheitsweisen das Noema (s. These 2). (shrink)

In this paper, the notions of Fα-categorical and Gα-categorical structures are introduced by choosing the isomorphism such that the function itself or its graph sits on the α-th level of the Ershov hierarchy, respectively. Separations obtained by natural graphs which are the disjoint unions of countably many finite graphs. Furthermore, for size-bounded graphs, an easy criterion is given to say when it is computable-categorical and when it is only G2-categorical; in the latter case it is not Fα-categorical for any recursive (...) ordinal α. (shrink)