One most common problem in reinforcement learning systems (e.g. Q-learning) is to reduce the number of trials to converge to an optimal policy. As one of the solution to the problem, k-certainty exploration method was proposed. Miyazaki reported that this method could determine an optimal policy faster than Q-learning in Markov decision processes (MDPs). This method is very efficient learning method. But, we propose an improvement plan that makes this method more efficient. In k-certainty exploration method, in case there is (...) no k-uncertainty rule (rules which aren’t selected more than k times) in current state, an agent sometimes walks randomly until it finds a state where it can select a k-uncertainty rule. We think that this behavior is not efficient. To reduce this useless behavior, we propose combining k-certainty exploration method with Dynamic programming (DP). Miyazaki’s system uses DP after all rules are executed at least k times. But, our method uses k-certainty exploration method along with DP during learning. Our method, takes two pattern actions. In case an agent can select k-uncertainty rules, one of these rules is selected at random as k-certainty exploration method. In another case there is no k-uncertainty rule, behavior of agent is different from the behavior of k-certainty exploration method. In that case, our method uses DP to compute an optimal policy for moving from a current state to a state in which some k-uncertainty rules remain. The model for DP is constructed by using only known states. The outline will be described below. First, an agent makes a map constructed by using only known states. In the map, goals are states in which there are k-uncertainty rules and arbitrary state values are set in these states. Point to which attention should be paid is that the map is not given from outside. It is made from only experience. Next, each state values of states in which there are only k-certainty rules in the map are computed by DP (we used Policy Iteration). Finally, an agent continues to select greedy action until it arrives at a state in which it can select a k-uncertainty rule. By this improvement, we expect it can determine an optimal policy faster than k-certainty exploration method. And we have verified that our exploration method can determine an optimal policy faster than k-certainty exploration method by computer simulation. (shrink)

Descartes uses the term experience (experientia; expérience) many time not only in the subject of physics but also in the one of metaphysics, especially in the arguments about the cogito and the free will: “he learns [‘I am thinking, therefore I am’] from experiencing in his own case that it is impossible that he should think without existing” (2ae Resp., AT-VII, 140; CSM-II, 100); “I cannot complain that the will or freedom of choice which I received from God is not (...) sufficiently extensive or perfect, since I know by experience that it is not restricted in any way” (Med., AT-VII, 56; CSM-II, 39), and so on. However, it is not clear what Descartes means by the term experientia; he never defines it. Then what is experience in Descartes’ metaphysics? In this paper, I intend to explore what Descartes meant by the term “experience” in the context of metaphysics. To be concrete, I first compare Descartes with earlier philosophers and clarify that Descartes’ use of the term “experience” has characteristics that were not recognized earlier (Section 1). I then clarify what the role of experience in Descartes is, while examining the validity of previous studies that equate Descartes’ experience with intuition and understanding (sections 2 and 3). (shrink)

It is sometimes argued that there is an analogy between time and modality: What is true of time, mutatis mutandis, should be true of modality, and vice versa. However, I think that the importance of this analogy has not been truly appreciated in the literature. In this paper, I try to offer a plausible account of the relationship between time and modality based on what is known as presentist ersatzism. If the attempt succeeds, it will be shown that ersatzists about (...) time are better able to explain what possible worlds are. (shrink)

The purpose of this study is to investigate the relationship between a firm’s strategy and consumers’ decisions in the presence of the paradox of choice and sharing personal information. The paradox of choice implies that having too many choices does not necessarily ensure happiness and sometimes having less is more. A new model is constructed introducing a factor of information sharing into the model of a previous study that embedded the paradox of choice only (Kinjo and Ebina in AI Soc (...) 30(2):291–297, 2015). A key feature of the model is its disutility function. It is demonstrated that if the sign of the cross derivative of the function is positive (negative) at the optimum, there is a positive (negative) correlation between the degree of sharing personal information chosen by the consumers and the number of products offered by the firm in its recommendation systems. It is also numerically indicated that the profit function of the firm becomes convex or concave depending on the shape of the disutility function. These results suggest that firms should carefully investigate the shape of the disutility function, under the paradox of choice and sharing personal information. (shrink)

The purpose of our study is to investigate the effects of the number of products, product attributes, and prices on consumer confusion, conduct a numerical analysis to check the robustness of the results, and present an example of the cell phone market in Japan. Following an ideal point model and embedding the number of products and product attributes, we clarify how these factors affect consumer confusion and purchase probability. We show that as the number of product attributes increases, the choice (...) probability of each product becomes equal, implying that consumer confusion occurs. This result is robust to the introduction of prices as strategic variables. (shrink)

In this paper, we generalize a result of Brown and Simpson [1] to prove that RCA0+Π0∞-BCT is conservative over RCA0 with respect to the set of formulae in the form ∃!Xφ, where φ is arithmetical. We also consider the conservation of Π00∞-BCT over Σb1-NIA+∇b1-CA.

Reading “The Tale of Genji”: Sources from the First Millennium. Edited by Thomas Harper and Haruo Shirane. New York: Columbia University Press, 2015. Pp. xx + 610. $65.

According to alethic pluralism, sentences belonging to different domains of discourse can be true by having different alethic (i.e., truth-constituting) properties. Against this pluralistic view, Jamin Asay has recently argued that pluralists' appeal to multiple alethic properties is ill-motivated because the main advantages of pluralism can already be obtained within the framework of standard truthmaker theory. In response to this objection, this paper argues that Asay's claim does not hold with respect to one of the central advantages of pluralism, namely, (...) the ability to offer a proper understanding of the realism/anti-realism debate. This is because, first, when simply construed, truthmaker theory can only provide an inadequate understanding of the debate, and second, when construed in certain ways that allow it to avoid inadequacy, it becomes committed to multiple alethic properties. (shrink)

The origins and consequences of warfare or largescale intergroup violence have been subject of long debate. Based on exhaustive surveys of skeletal remains for prehistoric hunter-gatherers and agriculturists in Japan, the present study examines levels of inferred violence and their implications for two different evolutionary models, i.e., parochial altruism model and subsistence model. The former assumes that frequent warfare played an important role in the evolution of altruism and the latter sees warfare as promoted by social changes induced by agriculture. (...) Our results are inconsistent with the parochial altruism model but consistent with the subsistence model, although the mortality values attributable to violence between hunter-gatherers and agriculturists were comparable. (shrink)

To investigate the cognitive processes underlying creative inspiration, we tested the extent to which viewing or copying prior examples impacted creative output in art. In Experiment 1, undergraduates made drawings under three conditions: copying an artist's drawing, then producing an original drawing; producing an original drawing without having seen another's work; and copying another artist's work, then reproducing that artist's style independently. We discovered that through copying unfamiliar abstract drawings, participants were able to produce creative drawings qualitatively different from the (...) model drawings. Process analyses suggested that participants' cognitive constraints became relaxed, and new perspectives were formed from copying another's artwork. Experiment 2 showed that exposure to styles of artwork considered unfamiliar facilitated creativity in drawing, while styles considered familiar did not do so. Experiment 3 showed that both copying and thoroughly viewing artwork executed using an unfamiliar style facilitated creativity in drawing, whereas merely thinking about alternative styles of artistic representation did not do so. These experiments revealed that deep encounters with unfamiliar artworks—whether through copying or prolonged observation—change people's cognitive representations of the act of drawing to produce novel artwork. (shrink)

This is a review essay on Daisuke Kachi’s recent book, Agents: Contemporary Substance Ontology (sic. Shunjusha, 2018). The book develops and partially defends an ontology that takes the category of substance as the most fundamental one. The author provides in it a new perspective on substance, which consists in characterizing substances as bearers of what he calls “substance modalities” (of which there are four kinds, that stem from the factors of essence, power, past persistence, and future persistence respectively). The first (...) part of this review essay gives an extended overview of Kachi’s book while the second discusses some problems it may face. (shrink)

A number of philosophers today endorse the view that material substances (e.g., cats, stones, atoms) can be analyzed as bundles of “particular properties” or “tropes”. Among several developments, the theory that Peter Simons proposed is seen as the most successful one. Simons’ theory seems to owe its high reputation to mainly two advantages which he claims for his theory: the capacity for avoiding infinite regress, and the explanatory adequacy for the phenomenon of change. In this paper, however, I try to (...) object to this high appraisal, by showing that the two alleged advantages in fact cannot be simultaneously secured by Simons’ position. To this aim, I proceed as follows: First, I present Simons’ theory and explain its alleged two advantages. Next, I take up Arda Denkel’s criticism and show that the explanatory adequacy will be lost unless Simons accepts a certain revision of his theory. Finally, I show that as a result of the revision needed, Simons’ position comes to lose the capacity for avoiding infinite regress in turn. (shrink)

Presentism is usually understood as the thesis that only the present exists whereas the rival theory of eternalism is usually understood as the thesis that past, present, and future things are all equally real. The significance of this debate has been threatened by the so-called triviality objection, which allegedly shows that the presentist thesis is either trivially true or obviously false: Presentism is trivially true if it is read as saying that everything that exists now is present, and it is (...) obviously false if read as saying that everything that has existed, exits or will exist is present. If eternalism is taken as the negation of presentism, it is also either trivially false or obviously true. In this paper, I try to respond to the triviality objection on behalf of presentism. In second section, I will examine how the argument proceeds. In third section, I will reflect on three possible ways to respond but will argue that none of them succeeds in giving a satisfactory solution. I will then try to clarify the core idea of presentism and to suggest that if we characterise presentism accurately, the problem will disappear. In fourth section, I will offer a plausible definition of presentism and will show how it can avoid the triviality objection and demonstrate why it is advantageous to accept the version of presentism I offer. (shrink)

This paper investigates the effects of group interaction in a storytelling situation for children using two robots: a reader robot and a listener robot as a side-participant. We developed a storytelling system that consists of a reader robot, a listener robot, a display, a gaze model, a depth sensor, and a human operator who responds and provides easily understandable answers to the children’s questions. We experimentally investigated the effects of using a listener robot and either one or two children during (...) a storytelling situation on the children’s preferences and their speech activities. Our experimental results showed that the children preferred storytelling with the listener robot. Although two children obviously produced more speech than one child, the listener robot discouraged the children’s speech regardless of whether one or two were listening. (shrink)

According to the subset view of realization, a property realizes another if the causal powers of the latter are a subset of those of the former. Against this view, some authors (in particular, Kevin Morris and Paul Audi) have argued that it has an untenable consequence that realizing properties are less fundamental than the properties they realize, because the subset view characterizes realized properties as parts (subsets) of their realizers whereas it is generally true that a part is prior to (...) its whole. This paper defends the subset view from this “part-whole” objection, by arguing that if we compare individual powers of realizer and realizee with particular attention to their manifestation conditions, it turns out that each power of a realizee is grounded in some power of its realizer. This grounding relation between powers, I shall argue, allows subset theorists to explain why a realizer is more fundamental than its realizee, even while having the latter as a part. (shrink)

According to the “truthmaker maximalism”, every true contingent proposition is made true by something in the world, called its truthmaker. Although at first sight the maximalism seems to be a natural position, it has serious difficulties, especially concerning negative truths. In view of this, many truthmaker theorists adopt some non-maximalist position. It is not clear, however, whether these non-maximalists are justified, since existing reasons to justify the non-maximalism are not good enough. In this paper, then, I shall propose a new (...) reason for the non-maximalism, which consists in the observation that the maximalism cannot acknowledge the widely accepted view that certain inferences involving logical constants are valid in the properly logical sense. (shrink)

One short passage on what is called the Receptacle in Plato’s Timaeus has been the subject of much controversy since Cherniss presented an alternative reading of it in 1954. In this paper, I criticize an influential argument presented by Zeyl for a traditional reading, and propose a new interpretation which adopts the alternative reading on important sentences of the passage, but is not accompanied by the defects of Cherniss’ interpretation.

Shōwashi e no renketsu -- Higashi Ajia kara no me -- Tennō to iu jiba -- Watashi no kaikōki -- Jikokuhyō katate ni ekisoba o.

本書は、2013年4月1日から2015年3月31日までの2年間、『みすず』誌に連載された「日記」を一書にしたものである。大学人としての仕事や作家として執筆に追われながら、政治学者として世の動向を分析し 、皇室の動きを観察し、鉄道旅行をする。日常から時代を解読する試み。.

The strong immanent realism (i.e., the view that there exist universals as entities capable of being wholly present wherever their instances are located) has been traditionally criticized for having certain absurd consequences. Although Gilmore (2003) replied to these criticisms by taking spatial relations involving universals as relativized to their locations, his reply has been rebutted by Keskinen et al. (2015). This paper aims to defend the strong immanent realism by proposing a new version of the relativization strategy, according to which (...) a spatial relation is to be relativized just to the extent that it contains universals or concrete particulars among its terms. This version, it will be argued, can satisfactorily address the objections hitherto posed to the strong immanent realism. (shrink)

There is a familiar tension between the two main components of non-reductive physicalism, which are physicalism, on the one hand, and the non-reducibility or autonomy of so-called special sciences (i.e., sciences other than physics), on the other. While it is often claimed that this tension can be satisfactorily resolved by adopting the subset account of realization (defended by e.g., Shoemaker (2001) and Wilson (2011)), this paper challenges that popular view, by elaborating some critical comments by Funkhouser (2014). Then, after examining (...) Funkhouser’s own position, this paper proposes a new way of resolving the aforementioned tension, which consists in refining the subset account’s analysis of realization on the basis of various dependence relations between causal powers. (shrink)