Introduction to Recent Developments in Living Technology

摘要

When the scientific and technological fruits of artificial life are embodied in technology with real practical use, sometimes the result can properly be called living technology [6]. Technology today is becoming increasingly lifelike, and there has recently been increasing foundational discussion of the broader scientific, socioeconomic, cultural, and ethical implications of living technology (e.g., [5, 7]). This special issue of Artificial Life describes recent developments in living technology, and samples current progress and applications in the works. The scientific core of the volume consists of seven articles describing new advances toward living technology. The volume also contains four articles about living technology's broader social, ethical, and political implications.Living technology is most simply defined as technology that is alive, but it is convenient to require that such technology furthermore be useful because of being lifelike [6] and not be a simple variant of existing life. We will call something lifelike if it has one or more of life's characteristic properties. Although there is controversy about the nature of life [4], there is a rough consensus about the characteristic properties exhibited by all typical living beings. Many also agree that a subset of life's characteristic properties form a small explanatorycore that can explain the rest of life's characteristic properties, although there is some disagreement about exactly which properties constitute that core. It is common to identify three core properties: Every life form (i) autonomously creates a boundary distinguishing itself from its environment, (ii) autonomously sustains itself through the synthesis of building blocks by harvesting energy and raw materials from the environment, and (iii) autonomously reproduces itself and evolves, through inheritance with variation of reproducible internally stored information that can activate and control the life form's crucial functions [14]. In addition to properties (i)–(iii), authors in this volume focus on other characteristic properties of life, including autonomy, homeostasis, robustness, adaptability, and the ability to learn from the environment (cf. Ikegami [11], Armstrong and Hanczyc [3], Gershenson [8], Montebelli et al. [12], Ackley [1], and Whitacre and Bender [18]). Different opinions about the core properties of life can generate different opinions about which technologies are living or lifelike.We assume that something is alive only if it has all of life's core properties. Once we have identified life's core properties, we can distinguish between living and merely lifelike technology (Table 1). Technologies with some but not all of life's core properties are merely lifelike, and technologies with more core properties are more lifelike, although this is only a partial ordering. Although lifelikeness cannot be measured precisely, one can still notice a general trend of more technologies becoming more lifelike; see Table 1.It should be noted that many discussions apply the term “living technology” to technologies that are merely lifelike, even though they lack some of life's core properties. These technologies can be called broadly living (i.e., either living or lifelike). To keep our terminology consistent and clear, we will distinguish between living and lifelike technology as indicated in Table 1.For example, one can distinguish between primary living technology, which is alive but contains no natural biological parts and did not come from a natural life form, and secondary living technology, whichdoes contain some living biological parts or came from a natural life form [6]. Table 2 combines the primary-secondary distinction with the living-lifelike distinction to define four categories of technologies: primary living technology, secondary living technology, primary lifelike technology, andsecondary lifelike technology. The table applies these categories to the technological achievements re