Many want to know what bitcoin is and how it works. But bitcoin is as complex as it is controversial, and relatively few have the technical background to understand it. In this paper, I offer an accessible on-ramp for understanding bitcoin in the form of a model. My model reveals both what bitcoin is and how it works. More specifically, it reveals that bitcoin is a fictional substance in a massively coauthored story on a network that automates and distributes jobs (...) normally entrusted to centralized publishing institutions. My model therefore falsifies a popular view according to which each bitcoin is a chunk of code. (shrink)

In the bitcoin whitepaper, Satoshi Nakamoto (2008: 2) defines an electronic coin as a chain of digital signatures. Many have since defined a bitcoin as a chain of digital signatures. This latter definition continues to appear in reports from central banks, advocacy centers, and governments, as well as in academic papers across the disciplines of law, economics, computer science, cryptography, management, and philosophy. Some have even used it to argue that what we now call bitcoin is not the real bitcoin. (...) The definition fails, however. This is important because the Chain Definition obscures Satoshi’s solution to a dilemma in the design of electronic cash, as well as the truth about bitcoin’s privacy and fungibility. In this article, I explain why the Chain Definition fails and what Satoshi likely endorsed instead. Along the way, I untangle some issues around bitcoin fungibility and clarify some others around the ontology of digital assets. (shrink)

Various strands of religious thought distinguish veneration from worship. According to these traditions, believers ought to worship God alone. To worship anything else, they say, is idolatry. And yet many of these same believers also claim to venerate—but not worship—saints, angels, images, relics, tombs, and even each other. But what's the difference? Tim Bayne and Yujin Nagasawa (2006: 302) are correct that “it seems to be extremely difficult to distinguish veneration from worship.” Many have argued throughout history that veneration collapses (...) into worship and that those who venerate saints or icons are guilty of idolatry. In this essay, we distinguish worship from veneration in two stages. First, we give a formal account of their difference. Drawing from St. John of Damascus (c. 675-749 AD), we argue that worship is a determinate of the determinable veneration. Second, we give more substantive accounts of both that explain their differences and similarities. Drawing again from St John, we argue that acts of veneration and worship signify subordination. Their difference, however, lies in the fact that worship alone requires absolute subordination. (shrink)

In this article, we describe what cryptocurrency is, how it works, and how it relates to familiar conceptions of and questions about money. We then show how normative questions about monetary policy find new expression in Bitcoin and other cryptocurrencies. These questions can play a role in addressing not just what money is, but what it should be. A guiding theme in our discussion is that progress here requires a mixed approach that integrates philosophical tools with the purely technical results (...) of disciplines like computer science and economics. Note: this article is the first entry within a two-part sequence on the Philosophy, Politics, and Economics of Cryptocurrency. (shrink)

In this article, we identify three key design dimensions along which cryptocurrencies differ -- privacy, censorship-resistance, and consensus procedure. Each raises important normative issues. Our discussion uncovers new ways to approach the question of whether Bitcoin or other cryptocurrencies should be used as money, and new avenues for developing a positive answer to that question. A guiding theme is that progress here requires a mixed approach that integrates philosophical tools with the purely technical results of disciplines like computer science and (...) economics. Note: this article is the second entry within a two-part sequence on the Philosophy, Politics, and Economics of Cryptocurrency. (shrink)

Paul Krugman and others deny that bitcoin has legitimate uses. Critics like Krugman also fail to distinguish bitcoin from other cryptocurrencies. But once we isolate bitcoin from the rest of the field, we see how special, and how useful, it is. In this chapter, we explain why bitcoin is unique among cryptocurrencies as a credibly neutral monetary asset and why this is important. Its uniqueness doesn’t owe entirely to its age (as the oldest) or market ranking (as the most valuable). (...) As a credibly neutral monetary asset, bitcoin solves problems for those in less than ideal circumstances. And beyond bitcoin’s functionality, its origin and surrounding culture also help to explain why people trust bitcoin more than any other cryptocurrency to solve these problems. Nothing else comes close. This gap between bitcoin and everything else has implications for policy-making, journalism, and academic research. (shrink)

Over the last half century, possible worlds have bled into almost every area of philosophy. In the metaphysics of modality, for example, philosophers have used possible worlds almost exclusively to illuminate discourse about metaphysical necessity and possibility. But recently, some have grown dissatisfied with possible worlds. Why are horses necessarily mammals? Because the property of being a horse bears a special relationship to the property of being a mammal, they say. Not because every horse is a mammal in every possible (...) world. Some have recently begun to use properties to develop rivals to possible worlds semantics which may someday compare in formal power and capture the different systems of modal logic. In this paper, I do two things. I first offer a quick primer on possible worlds semantics. Then I discuss three rivals and the work they have left to do. (shrink)

We sometimes say things like this: “being an animal is part of being a dog.” We associate the part with a precondition for exemplifying the whole. A new semantics for modal logic results when we take this way of speaking seriously. We need not treat necessary truths as truths in all possible worlds. Instead, we may treat them as preconditions for the existence of any world at all. I present this semantics for modal propositional logic and argue that it operates (...) on a more basic level of modal reality than possible world semantics. (shrink)

In common treatments of deontic logic, the obligatory is what is true in all deontically ideal possible worlds. In this article, I offer a new semantics for Standard Deontic Logic with Leibnizian intensions rather than possible worlds. Even though the new semantics furnishes models that resemble Venn diagrams, the semantics captures the strong soundness and completeness of Standard Deontic Logic. Since, unlike possible worlds, many Leibnizian intensions are not maximally consistent entities, we can amend the semantics to invalidate the inference (...) rule which ensures that all tautologies are obligatory. I sketch this amended semantics to show how it invalidates the rule in a new way. (shrink)

Leibniz's conceptual containment theory says that singular propositions of the form a is F are true when the complete concept of being a contains the concept of being F. In this paper, I provide a new semantics for first-order logic built around this idea. The semantics resolves longstanding problems for Leibniz's theory and can represent, without possible worlds, both hyperintensional distinctions among properties and a certain kind of presumably impossible situation that standard approaches cannot represent. The semantics also captures the (...) strong soundness and completeness of classical first-order logic. (shrink)

This chapter offers an interpretation of Gottfried Wilhelm Leibniz’s idealism. Despite Leibniz’s frequent claim that the universe ultimately boils down to monads, he also sometimes appears to say that the world’s fundamental furniture includes extended, corporeal substances. Here, I examine Leibniz’s views about the relationship between monads and the material world, especially in connection with material bodies and corporeal substances.

In On What Matters, Derek Parfit enters the debate between actualists and possibilists. This debate concerns mere possibilia, possible but non-actual things such as golden mountains and talking donkeys. Roughly, possibilism says that there are such things, and actualism says that there are not. Parfit not only argues for possibilism but also argues that some self-proclaimed actualists are, in fact, unwitting possibilists. -/- I argue that although Parfit’s arguments do not fully succeed, they do highlight a tension within the frameworks (...) of many actualists. Many actualists conscript abstract objects into the role of "possible worlds" to avoid quantifying over mere possibilia. But, in doing so, actualists must quantify over mere possibilia anyway. When we alleviate this tension, a Parfit-friendly form of actualism arguably remains. This form of actualism says that while everything that exists is actual, it is also true in some sense that there are mere possibilia. (shrink)