Michael J. Raven

There is a long history of cryptographic hash functions, i.e. functions mapping variable-length strings to fixed-length strings, and such functions are also expected to enjoy certain security properties. Hash functions can be effected via modular arithmetic, permutation-based schemes, chaotic mixing, and so on. Herein we introduce the notion of an artificial-life (ALife) hash function (ALHF), whereby the requisite mixing action of a good hash function is accomplished via ALife rules that give rise to complex evolution of a given system. Various security tests have been run, and the results reported for examples of ALHFs.

Impostors are pseudo-problems masquerading as genuine problems. Impostors should be exposed. The problem of change appears genuine. But some, such as Hofweber ( 2009 ) and Rychter ( 2009 ), have recently denounced it as an impostor. They allege that it is mysterious how to answer the meta - problem of saying what problem it is: for even if any problem is genuinely about change per se, they argue, it is either empirical or trivially dissolved by conceptual analysis. There is indeed an impostor in our midst. But it is the meta-problem of change. I defend the appearance that the problem of change is a genuine metaphysical problem about change. This vindicates philosophers’ lasting interest in it. It also illuminates what makes a problem metaphysical, how metaphysics relates to other inquiries, and how best to respond to attempts to undermine metaphysical problems.