In the natural world, individual organisms can adapt as their environment changes. In most in silico evolution, however, individual organisms tend to consist of rigid solutions, with all adaptation occurring at the population level. If we are to use artificial evolving systems as a tool in understanding biology or in engineering robust and intelligent systems, however, they should be able to generate solutions with fitness-enhancing phenotypic plasticity. Here we use Avida, an established digital evolution system, to investigate the selective pressures (...) that produce phenotypic plasticity. We witness two different types of fitness-enhancing plasticity evolve: static- execution-flow plasticity, in which the same sequence of actions produces different results depending on the environment, and dynamic-execution-flow plasticity, where organisms choose their actions based on their environment. We demonstrate that the type of plasticity that evolves depends on the environmental challenge the population faces. Finally, we compare our results to similar ones found in vastly different systems, which suggest that this phenomenon is a general feature of evolution. (shrink)
Journal of Experimental and Theoretical Artificial Intelligence (Vol. 19, No. 1, 2007) What is the difference between a simulation of X and simply another instance of X? Is there a point at which the ‘‘virtual reality’’ of a model becomes the real thing? This paper examines these questions using cases taken from recent developments in evolutionary engineering and artificial life research. By implementing the Darwinian mechanism and setting it to work on a design problem, scientists and engineers find that evolution (...) not only can improve prior designs, but also produce novel technological solutions. Artificial life systems Tierra and Avida which operate at a higher level of abstraction than evolutionary engineering applications. I analyze simulation as a rational concept ‘‘S simulates R’’ and argue that it always includes some relevant property P, of R, that is captured but that there is always also some other that it omits, and that pragmatic factors fix what counts as relevant. The border between a simulation and an instance can change depending upon the context. I show that in one sense, evo-technology and artificial life simulate organic evolution, but in another relevant sense they are instances of evolution itself. Biologists can use such systems to experimentally test evolutionary hypotheses such as those involving the evolution of complex features and altruism. This analysis suggests lines for future research on broader questions about models classification and confirmation. (shrink)
With its metaphors of war and calls to martyrdom, the Intelligent Design (ID) Creationist movement is reigniting old animosities between religion and science. This article discusses several of the key religious controversies involving ID Creationism, especially the flaws in William Dembski’s defense of ID. It also rebuts his charge that science’s naturalistic method is a “pre-modern sin” and shows how this is a problem not for science but for ID, which aims to resurrect occult explanations. Contrary to Demski’s claim, methodological (...) naturalism is not a constraint upon the world but a constraint upon science. The difference between science and creationism is like the difference between seeing hurricanes and thunderstorms as natural disasters rather than as acts of God. (shrink)
Teach the Controversy? Kansas just can't get a break. In 1999, the state became an international laughingstock when creationists on the State Board of Education, led by Steve Abrams, gutted what would have been a model science curriculum, removing the theme of evolution as well as mentions of the Big Bang and the geological timescale (Pennock, 1999b, 2000). These board members and the creationist groups that assisted them seemed to confirm every stereotype of Kansas as an ignorant backwater. The creationists (...) lost their majority on the Board in the next election when sensible I~sans made their voices heard, and the standat'ds were righted. But freedom Ã¢â¬â in this case, freedom from the tyranny of ignoranceÃ¢â¬â demands eternal vigilance, and science defenders were too quick to test on theit laurels. Another election passed and in 2005 Steve Abrams and his allies. were at.. (shrink)
In his keynote address at a recent Intelligent Design (ID) conference at Biola University, ID leader William Dembski began by quoting "a well-known ID sympathizer" whom he had asked to assess the current state of the ID movement. Dembski explained that he had asked because, "after some initial enthusiasm on his part three years ago, his interest seemed to have flagged" (Dembski 2002). The sympathizer replied that..
I am Associate Professor of Science & Technology Studies at Michigan State University’s Lyman Briggs School of Science and Associate Professor of Philosophy in the Department of Philosophy. I’m also a faculty member in MSU’s Ecology & Evolutionary Biology and Behavior Program and in the Department of Computer Science.
One new development in the ongoing creationism/ evolution controversy has been the proposal to institute optout policies that would allow creationist parents to exempt their children from any instruction involving evolution. By way of an explanation of some of the philosophical issues at play in the debate over evolution and the nature of science, this article shows the educational folly of such policies. If evolution is taught properly, it should not be possible to opt out of it without opting out (...) of biology. Moreover, if Intelligent Design creationist criticisms of evolution and scientific naturalism were taken as the basis for opting out, then the effect would be even more radical and would require opting out of science entirely. (shrink)
��This paper investigates how an evolutionary al- gorithm with an indirect encoding exploits the property of phenotypic regularity, an important design principle found in natural organisms and engineered designs. We present the ﬁrst comprehensive study showing that such phenotypic regularity enables an indirect encoding to outperform direct encoding con- trols as problem regularity increases. Such an ability to produce regular solutions that can exploit the regularity of problems is an important prerequisite if evolutionary algorithms are to scale to high-dimensional real-world (...) problems, which typically contain many regularities, both known and unrecognized. The indirect encoding in this case study is HyperNEAT, which evolves artiﬁcial neural networks (ANNs) in a manner inspired by concepts from biological development. We demonstrate that, in contrast to two direct encoding controls, HyperNEAT produces both regular behaviors and regular ANNs, which enables HyperNEAT to signiﬁcantly outperform the direct encodings as regularity increases in three problem domains. We also show that the types of regularities HyperNEAT produces can be biased, allowing domain knowledge and preferences to be injected into the search. Finally, we examine the downside of a bias toward regularity. Even when a solution is mainly regular, some irregularity may be needed to perfect its functionality. This insight is illustrated by a new algorithm called HybrID that hybridizes indirect and direct encodings, which matched HyperNEAT’s performance on regular problems yet outperformed it on problems with some irregularity. HybrID’s ability to improve upon the performance of HyperNEAT raises the question of whether indirect encodings may ultimately excel not as stand-alone algorithms, but by being hybridized with a further process of reﬁnement, wherein the indirect encoding produces patterns that exploit problem regu-. (shrink)
Resistance to paying war taxes that stems from a principled pacifism is not the same as tax-dodging and should be accommodated in the law by broadening the scope of Conscientious Objector (CO) status and by legislating a nonmilitary alternative fund so COs may redirect their tax money to peaceful uses. Using the religious example of the Society of Friends (Quakers) and various secular examples of pacifism I show that resisters’ conscientious opposition to paying for war is of a kind with (...) their conscientious refusal to carry arms. Their refusal to cooperate with military taxation is not disdain of the rule of law, but is a respectful form of civil disobedience. It is in the interest of justice for a liberal democracy to provide an option for conscientious objectors so they may satisfy their moral scruples without having to break the law. (shrink)
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Because evolution in natural systems happens so slowly, it is dif- ficult to design inquiry-based labs where students can experiment and observe evolution in the way they can when studying other phenomena. New research in evolutionary computation and artificial life provides a solution to this problem. This paper describes a new A-Life software environment – Avida-ED – in which undergraduate students can test evolutionary hypotheses directly using digital organisms that evolve on their own through the very mechanisms that Darwin discovered.
1 I would like to thank the Association for Philosophy of Education for inviting me to address this question at their meeting in December 1998, at the American Philosophical Association Eastern Division Meeting. This paper is a slightly revised version of that address. Besides including some additional references, it incorporates my response to Alvin Plantinga, who gave the commentary address on my original paper.
In his review of my book Tower of Babel: The Evidence against the New Creationism that he recently published in The Weekly Standard under the title “The God of Science: The Case for Intelligent Design” (Behe 1999), Michael Behe takes me to task for criticizing the “intelligent design” group, of which he is a member, in the same pages that I criticize Genesis literalists and other religious anti-evolutionists. He writes.
We investigate the evolution of memory usage in environments where information about past experience is required for optimal decision making. For this study, we use digital organisms, which are self-replicating computer programs that are subject to mutations and natural selection. We place the digital organisms in a range of experimental environments: simple ones where environmental cues indicate that a specific action should be taken (e.g., turn left to find food) as well as slightly more complex ones where cues refer to (...) prior experience (e.g., repeat the action indicated by the previous cue). We demonstrate that flexible behaviors evolve in each of these environments, often leading to clever survival strategies. Additionally, memory usage evolves only when it provides a significant advantage and organisms will often employ surprisingly successful strategies that do not use memory. However, the most powerful strategies we found all made effective use of memory. (shrink)
That Intelligent Design Creationism rejects the methodological naturalism of modern science in favor of a premodern supernaturalist worldview is well documented and by now well known. An irony that has not been sufficiently appreciated, however, is the way that ID Creationists try to advance their premodern view by adopting (if only tactically) a radical postmodern perspective. This paper will reveal the deep threads of postmodernism that run through the ID Creationist movement’s arguments, as evidenced in the writings and interviews of (...) its key leaders. Seeing their arguments and activities from this perspective highlights the danger to science posed by both ID Creationism and radical postmodernism. (shrink)
Evolutionary algorithms typically use direct encodings, where each element of the phenotype is specified independently in the genotype. Because direct encodings have difficulty evolving modular and symmetric phenotypes, some researchers use indirect encodings, wherein one genomic element can influence multiple parts of a phenotype. We have previously shown that Hyper- NEAT, an indirect encoding, outperforms FT-NEAT, a direct-encoding control, on many problems, especially as the regularity of the problem increases. However, HyperNEAT is no panacea; it had difficulty accounting for irregularities (...) in problems. In this paper, we propose a new algorithm, a Hybridized Indirect and Direct encoding (HybrID), which discovers the regularity of a problem with an indirect encoding and accounts for irregularities via a direct encoding. In three different problem domains, HybrID outperforms HyperNEAT in most situations, with performance improvements as large as 40%. Our work suggests that hybridizing indirect and direct encodings can be an effective way to improve the performance of evolutionary algorithms. (shrink)
What is the definition of life? Artificial life environments provide an interesting test case for this classical question. Understanding what such systems can tell us about biological life requires negotiating the tricky conceptual boundary between virtual and real life forms. Drawing from Wittgenstein’s analysis of the concept of a game and a Darwinian insight about classification, I argue that classifying life involves both causal and pragmatic elements. Rather than searching for a single, sharp definition, these considerations suggest that life is (...) a cluster concept with fuzzy boundaries and that there are multiple legitimate ways to make the notion precise for different scientific purposes. This pluralist, realist account avoids unnecessary border disputes by emphasizing how science negotiates such questions in relation to theory and evidence. I also discuss several objections to this approach, including a “moral hesitation” some have to allowing broader application of the concept of life to include artificial life. (shrink)
In the 2005 Kitzmiller v Dover Area School Board case, a federal district court ruled that Intelligent Design creationism was not science, but a disguised religious view and that teaching it in public schools is unconstitutional. But creationists contend that it is illegitimate to distinguish science and religion, citing philosophers Quinn and especially Laudan, who had criticized a similar ruling in the 1981 McLean v. Arkansas creation-science case on the grounds that no necessary and sufficient demarcation criterion was possible and (...) that demarcation was a dead pseudo-problem. This article discusses problems with those conclusions and their application to the quite different reasoning between these two cases. Laudan focused too narrowly on the problem of demarcation as Popper defined it. Distinguishing science from religion was and remains an important conceptual issue with significant practical import, and philosophers who say there is no difference have lost touch with reality in a profound and perverse way. The Kitzmiller case did not rely on a strict demarcation criterion, but appealed only to a “ballpark” demarcation that identifies methodological naturalism (MN) as a “ground rule” of science. MN is shown to be a distinguishing feature of science both in explicit statements from scientific organizations and in actual practice. There is good reason to think that MN is shared as a tacit assumption among philosophers who emphasize other demarcation criteria and even by Laudan himself. (shrink)
Key Words creation science, evolution education s Abstract Creationism, the rejection of evolution in favor of supernatural design, comes in many varieties besides the common young-earth Genesis version. Creationist attacks on science education have been evolving in the last few years through the alliance of different varieties. Instead of calls to teach “creation science,” one now ﬁnds lobbying for “intelligent design” (ID). Guided by the Discovery Institute’s “Wedge strategy,” the ID movement aims to overturn evolution and what it sees as (...) a pernicious materialist worldview and to renew a theistic foundation to Western culture, in which human beings are recognized as being created in the image of God. Common ID arguments involving scientiﬁc naturalism, “irreducible complexity,” “complex speciﬁed information,” and “icons of evolution,” have been thoroughly examined and refuted. Nevertheless, from Kansas to Ohio to the U.S. Congress, ID continues lobbying to teach the controversy, and scientists need to be ready to defend good evolution education. (shrink)
Some philosophers suggest that the development of scientificknowledge is a kind of Darwinian process. The process of discovery,however, is one problematic element of this analogy. I compare HerbertSimon's attempt to simulate scientific discovery in a computer programto recent connectionist models that were not designed for that purpose,but which provide useful cases to help evaluate this aspect of theanalogy. In contrast to the classic A.I. approach Simon used, ``neuralnetworks'' contain no explicit protocols, but are generic learningsystems built on the model of (...) the interconnections of neurons in thebrain. I describe two cases that take the connectionist approach a stepfurther by using genetic algorithms, a form of evolutionary computationthat explicitly models Darwinian mechanisms. These cases show thatDarwinian mechanisms can make novel discoveries of complex, previouslyunknown patterns. With some caveats, they lend support to evolutionaryepistemology. (shrink)
use of the Hempelian instance confirmation relation, there are asymmetries than can be exploited if we adopt an "ontic" confirmation theory that uses a causal notion of evidential relevance. I sort out a variety of interpretive confusions about the intended content of the definition of grue and show how the causal approach resolves each in a way that is not paradoxical.
Phillip Johnson claims that Creationism is a better explanation of the existence and characteristics of biological species than is evolutionary theory. He argues that the only reason biologists do not recognize that Creationist's negative arguments against Darwinism have proven this is that they are wedded to a biased ideological philosophy —Naturalism — which dogmatically denies the possibility of an intervening creative god. However,Johnson fails to distinguish Ontological Naturalism from Methodological Naturalism. Science makes use of the latter and I show how (...) it is not dogmatic but follows from sound requirements for empirical evidential testing. Furthermore, Johnson has no serious alternative type of positive evidence to offer for Creationism, and purely negative argumentation, despite his attempt to legitimate it, will not suffice. (shrink)
Could an ethical theory ever play a substantial evidential role in a scientific argument for an empirical hypothesis? InThe Descent of Man, Darwin includes an extended discussion of the nature of human morality, and the ethical theory which he sketches is not simply developed as an interesting ramification of his theory of evolution, but is used as a key part of his evidence for human descent from animal ancestors. Darwin must rebut the argument that, because of our moral nature, humans (...) are essentially different in kind from other animals and so had to have had a different origin. I trace his causal story of how the moral sense could develop out of social instincts by evolutionary mechanisms of group selection, and show that the form of Utilitarianism he proposes involves a radical reduction of the standard of value to the concept of biological fitness. I argue that this causal analysis, although a weakness from a normative standpoint, is a strength when judged for its intended purpose as part of an evidential argument to confirm the hypothesis of human descent. (shrink)