What am I? Virtual Machines and the Mind/Body Problem

When your word processor or email program is running on your computer, this creates a "virtual machine” that manipulates windows, files, text, etc. What is this virtual machine, and what are the virtual objects it manipulates? Many standard arguments in the philosophy of mind have exact analogues for virtual machines and virtual objects, but we do not want to draw the wild metaphysical conclusions that have sometimes tempted philosophers in the philosophy of mind. A computer file is not made of epiphenomenal ectoplasm. I argue instead that virtual objects are "supervenient objects". The stereotypical example of supervenient objects is the statue and the lump of clay. To this end I propose a theory of supervenient objects. Then I turn to persons and mental states. I argue that my mental states are virtual states of a cognitive virtual machine implemented on my body, and a person is a supervenient object supervening on his cognitive virtual machine

Is Google the next Microsoft? Competition, Welfare and Regulation in Internet Search

Internet search (or perhaps more accurately `web-search') has grown exponentially over the last decade at an even more rapid rate than the Internet itself. Starting from nothing in the 1990s, today search is a multi-billion dollar business. Search engine providers such as Google and Yahoo! have become household names, and the use of a search engine, like use of the Web, is now a part of everyday life. The rapid growth of online search and its growing centrality to the ecology of the Internet raise a variety of questions for economists to answer. Why is the search engine market so concentrated and will it evolve towards monopoly? What are the implications of this concentration for different `participants' (consumers, search engines, advertisers)? Does the fact that search engines act as `information gatekeepers', determining, in effect, what can be found on the web, mean that search deserves particularly close attention from policy-makers? This paper supplies empirical and theoretical material with which to examine many of these questions. In particular, we (a) show that the already large levels of concentration are likely to continue (b) identify the consequences, negative and positive, of this outcome (c) discuss the possible regulatory interventions that policy-makers could utilize to address these

The Control of Porting in Two-Sided Markets

A sizable literature has grown up in recent years focusing on two-sided markets in which economies of scale combined with complementarities between a platform and its associated ‘software’ or ‘services’ can generate indirect network effects (that is positive feedback between the number of consumers using that platform and the utility of an individual consumer). In this paper we introduce a model of ‘porting’ in such markets where porting denotes the conversion of ‘software’ or ‘services’ developed for one platform to run on another. Focusing on the case where a dominant platform exists we investigate the impact on equilibrium and the consequences for welfare of the ability to control porting. Specifically, we show that the welfare costs associated with the ‘control of porting’ may be more significant than those arising from pricing alone. This model and its associated results are of particular relevance because of the light they shed on debates about the motivations and effects of actions by a dominant platform owner. Recent examples of such debates include those about Microsoft’s behaviour both in relation to its operating system and its media player, Apple’s behaviour in relation to its DRM and iTunes platform, and Ebay’s use of the cyber-trespass doctrine to prevent access to its site

Innovation and Imitation with and without Intellectual Property Rights

An extensive empirical literature indicates that returns from innovation are appropriated primarily via mechanisms other than formal intellectual property rights -- and that `imitation' is itself a costly activity. However most theory assumes the pure nonrivalry of `ideas' with its implication that, in the absence of intellectual property, innovation (and welfare) is zero. This paper introduces a formal model of innovation based on imperfect competition in which imitation is costly and an innovator has a first-mover advantage. Without intellectual property, a significant amount of innovation still occurs and welfare may actually be higher than with intellectual property.Innovation; Imperfect Competition; Intellectual Property; Imitation

Realisations of Finite-Sample Frequency-Selective Filters

A filtered data sequence can be obtained by multiplying the Fourier ordinates of the data by the ordinates of the frequency response of the filter and by applying the inverse Fourier transform to carry the product back to the time domain. Using this technique, it is possible, within the constraints of a finite sample, to design an ideal frequency-selective filter that will preserve all elements within a specified range of frequencies and that will remove all elements outside it. Approximations to ideal filters that are implemented in the time domain are commonly based on truncated versions of the infinite sequences of coefficients derived from the Fourier transforms of rectangular frequency response functions. An alternative to truncating an infinite sequence of coefficients is to wrap it around a circle of a circumference equal in length to the data sequence and to add the overlying coefficients. The coefficients of the wrapped filter can also be obtained by applying a discrete Fourier transform to a set of ordinates sampled from the frequency response function. Applying the coefficients to the data via circular convolution produces results that are identical to those obtained by a multiplication in the frequency domain, which constitutes a more efficient approach.Signal extraction; Linear filtering; Frequency-domain analysis

Cumulative Innovation, Sampling and the Hold-Up Problem

With cumulative innovation and imperfect information about the value of innovations, intellectual property rights can result in hold-up and therefore it may be better not to have them. Extending the basic cumulative innovation model to include `sampling' by second-stage firms, we find that the lower the cost of sampling, or the larger the differential between high and low value second-stage innovations, the more likely it is that a regime without intellectual property rights will be preferable. Thus, technological change which reduces the cost of encountering and trialling new `ideas' implies a reduction in the socially optimal level of rights such as patent and copyright.Cumulative Innovation; Hold-Up; Sampling; Intellectual Property

The Classical Econometric Model

A compendium is presented of the various approaches that may be taken in deriving the estimators of the simultaneous-equations econometric model according to the principle of maximum likelihood. The structural equations of the model have the character both of a regression equation and of an errors-in-variables equation. This partly accounts for way in which the various approaches that have been followed appear to differ widely. In the process of achieving a synthesis of the methods of estimation, some elements that have been missing from the theory are supplied.

Investigating Economic Trends And Cycles

Methods are described for extracting the trend from an economic data sequence and for isolating the cycles that surround it. The latter often consist of a business cycle of variable duration and a perennial seasonal cycle. There is no evident point in the frequency spectrum where the trend ends and the business cycle begins. Therefore, unless it can be represented by a simple analytic function, such as an exponential growth path, there is bound to be a degree of arbitrariness in the definition of the trend. The business cycle, however defined, is liable to have an upper limit to its frequency range that falls short of the Nyquist frequency, which is the maximum observable frequency in sampled data. This must be taken into account in fitting an ARMA model to the detrended data.