Why There Can be No Reliable Relativistic Hypercomputers

mh hypercomputation

Figure 1: Simple model of computation in an M-H space-time.

A hypercomputer is able to finish infinitely many computations in finite time. Any user could hence get all the answers to any computable question rather quickly, including for instance the greatest prime number. Given our laws of physics, such devices cannot be built. However, there are theories of hypercompuation that makes use of relativistic space-time curvature. These would have to operate though for an infinite amount of time in their little pocket of the universe. This requires a rather reliable machine. Here I argue against such reliability. I start by examining the physical Church-Turing (PhCT) thesis and its interplay with supertasks and hypercomputation. I will introduce Piccinini’s usability constraint for testing the viability of possible counterexamples to PhCT and will examine relativistic hypercomputation to that end. I propose that ontic pancomputationalism is a possible solution of an infinitely persisting computation, but note that instead of the machine, the observer now perishes and also the computing function becomes unusable. Quintessentially, I conclude that on the reliability constraint alone, all hypercomputation will fail in nomologically accessible worlds.

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Review of Chapter 5 “Physics for Philosophers” from Craig Bourne’s “A Future for Presentism”

In his book chapter, Bourne introduces the layman reader to the basic non-mathematical postulates of special relativity. He begins by presenting our common-sense intuitions about the additivity of speeds between objects, which turns out to be violated, since no speed can be added to exceed the speed of light c. This has some counterintuitive consequences for concepts like simultaneity and the uniform passage of time.

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David Lewis Established the Logical Possibility of Time Travel

kdlsj442After just a single episode of Doctor Who, you’ll know that time travel does not come without its share of headaches. There are a great many paradoxes, most famously those that ask how changing the past in a way that eliminates you from existence could allow you to change the past in the first place. Intuitively for many, time travel is consequently an inconsistent notion. Here I defend David Lewis’ claim that backwards time travel (BTT) need not entail logical contradictions. I start by outlining his exposition of BTT, the resulting grandfather paradox and his compossibility solution. I then move to a critique of this answer from unexplained constraints on the traveller. I argue that it misconstructs Lewis’ argument and although puzzling fails to show that BTT entails contradiction. I conclude that prima facie Lewis did establish the logical possibility of BTT.

Picture: A police box on the Grassmarket in Edinburgh

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No More Humean Supervenience about Laws of Nature

1_gammaIf you are a Humean, you may believe that laws of nature do not govern, but rather neatly fit the overall pattern of everything that happens in the universe. A law then would not have much governing to do beyond offer an explanation. Unfortunately, there are empirical reasons to believe that this may not be so. Here I try to make the case for some of these. After constructing Humean Supervenience as conjunction of Modal Combinatorialism, Supervenience and Nomological Reduction, I consider quantum-entanglement to show how Modal Combinatorialism is violated leading to a downfall of HS in general. I will consider a response to this by Loewer and conclude that on empirical grounds HS under Lewis’ formulation fails, although its basic intuition of non-governing laws persists.

 

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The Case for Boyd’s Homeostatic Property Clusters

clustet342What makes a bird a bird? Well, our taxonomy of course. What if this changes though over time and evolution? What if the properties we associate with birds one day no longer exist or only some? Boyd offers an account of classifying natural kinds, such as birds or psychiatric disorders based on properties which usually cluster together because of causal relations between them. I try to defend that view here. After thoroughly setting up the HPC theory in contrast to essentialism, with particular emphasis on its homeostatic causal mechanism, I shall then try to defend this mechanism against essentialist attack. I will examine how clustering is contingent on the causal structure of the world with examples from biological taxa and psychiatry.

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Against Money as Measure between Prudential Values

Money is not a good common measure for prudential values in one-person cases. When considering opportunity costs in daily decisions, watching Dr Who vs watching Inspector Lynley, it fails quickly to meet the standard we would need in a viable theory of value. I begin the rationale for this by introducing the informed-desire account, move on to the resulting problem of incommensurable values and their measurement. I then propose money as solution to those problems. Afterwards I will discuss three counterexamples from investment, consumer rationality and money as social relation which will lead this post to conclude that although money has merits in explaining how to measure prudential values, it ultimately cannot overcome the counterexamples.

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Overdetermination and the Autonomy of the Mental

The problem of mental causation from the overdetermination argument could possibly be solved by rejecting the premise of physical completeness. I begin by elaborating the problem, give a priori reasons to reject the completeness of physics and examine the resulting problems associated with emergentism. I shall then move on to a posteriori reasons for rejecting the afore mentioned premise from the fields of quantum-electrodynamics (QED) and quantum chemistry (QC). I will conclude that although these reasons are justified, a rejection of the completeness of physics is but the first step to a satisfying account of mental causation.

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