Online research in philosophy

I conduct an empirical analysis of the temporally asymmetric character of our epistemic access to the world by providing an experimental scheme whose results represent the core empirical content of the epistemic asymmetry. I augment this empirical content by formulating a gedanken experiment inspired by a proposal from David Albert. This second experiment cannot be conducted using any technology that is likely to be developed in the foreseeable future, but the expected results help us to state an important constraint on (...) our ability to know the future. Finally, I show that a third experiment concerning precognition, described by Michael Scriven and John Mackie, does not characterize any additional empirical content but does help to illustrate why it is unlikely that any precognition exists. (shrink)

I provide a comprehensive metaphysics of causation based on the idea that fundamentally things are governed by the laws of physics, and that derivatively difference-making can be assessed in terms of what fundamental laws of physics imply for hypothesized events. Highlights include a general philosophical methodology, the fundamental/derivative distinction, and my mature account of causal asymmetry.

Thinking about time travel is an entertaining way to explore how to understand time and its location in the broad conceptual landscape that includes causation, fate, action, possibility, experience, and reality. It is uncontroversial that time travel towards the future exists, and time travel to the past is generally recognized as permitted by Einstein’s general theory of relativity, though no one knows yet whether nature truly allows it. Coherent time travel stories have added flair to traditional debates over the metaphysical (...) status of the past, the reality of temporal passage, and the existence of free will. Moreover, plausible models of time travel and time machines can be used to investigate the subtle relation between space-time structure and causality. -/- It surveys some philosophical issues concerning time travel and should serves as a quick introduction. It includes a new and improved way to define a time machine. (shrink)

Backtracking influence is influence that zigzags in time. For example, backtracking influence exists when an event E_1 makes an event E_2 more likely by way of a nomic connection that goes from E_1 back in time to an event C and then forward in time to E_2. I contend that in our local region of spacetime, at least, backtracking influence is redundant in the sense that any existing backtracking influence exerted by E_1 on E_2 is equivalent to E_1's temporally direct (...) influence on E_2. I prove the redundancy of backtracking influence using several plausible physical principles without assuming any fundamental temporal or causal asymmetry. This explanation can play a prominent role in an account of why causation appears to be objectively asymmetric regardless of whether the fundamental laws are symmetric. (shrink)

I sketch a philosophical program called ‘Empirical Fundamentalism,’ whose signature feature is the extensive use of a distinction between fundamental and derivative reality. Within the framework of Empirical Fundamentalism, derivative reality is treated as an abstraction from fundamental reality. I show how one can understand reduction and supervenience in terms of abstraction, and then I apply the introduced machinery to understand the relation between water and H2O, mental states and brain states, and so on. The conclusion is that such relations (...) can be understood either as metaphysical contingencies or as necessary type-identities. (shrink)

An explanation of our seeming inability to influence the past.

Relativistic quantum theories are equipped with a background Minkowski spacetime and non-relativistic quantum theories with a Galilean space-time. Traditional investigations have distinguished their distinct space-time structures and have examined ways in which relativistic theories become sufficiently like Galilean theories in a low velocity approximation or limit. A different way to look at their relationship is to see that both kinds of theories are special cases of a certain five-dimensional generalization involving no limiting procedures or approximations. When one compares them, striking (...) features emerge that bear on philosophical questions, including the ontological status of the wave function and time reversal invariance. (shrink)

Conceptual analyses can be subdivided into two classes, good and evil. Em- pirical analysis is the good kind, routinely practiced in the sciences. Orthodox analysis is the malevolent version that plagues philosophical discourse. In this paper, I will clarify the difference between them, provide some reasons to prefer good over evil, and illustrate their consequences for the metaphysics of causation. By conducting an empirical analysis of causation rather than an orthodox analysis, one can segregate the genuine metaphysical problems that need (...) to be addressed from the many pseudo-problems that have long dogged traditional accounts of causation. (shrink)

I defend what may loosely be called an eliminativist account of causation by showing how several of the main features of causation, namely asymmetry, transitivity, and necessitation (or sometimes probability-raising), arise from the combination of fundamental dynamical laws and a special constraint on the macroscopic structure of matter in the past. At the microscopic level, the causal features of necessitation and transitivity are grounded, but not the asymmetry. At the coarse-grained level of the macroscopic physics, the causal asymmetry is grounded, (...) but not the necessitation or transitivity. Thus, at no single level of description does the physics justify the conditions that are taken to be constitutive of causation. Nevertheless, if we mix our reasoning about the microscopic and macroscopic descriptions, the structure provided by the dynamics and special initial conditions can justify the folk concept of causation to a significant extent. I explain why our causal concept works so well even though at bottom it is comprised of a patchwork of principles that don't mesh well. (shrink)

The possibility of time travel, as permitted in General Relativity, is responsible for constraining physical fields beyond what the laws normally require. In the special case where time travel is limited to a single object returning to the past and interacting with itself, consistency constraints can be avoided if the dynamics is continuous and the object’s state space satisfies a certain topological requirement: that all null-homotopic mappings from the state-space to itself have some fixed point. Where consistency constraints do exist, (...) no new physics is needed to enforce them. All one needs for their accommodation is to grant a kind of law-like status to some kinds of global boundary conditions. (shrink)

The possibility of time travel, as permitted in General Relativity, is responsible for constraining physical fields beyond what laws of nature would otherwise require. In the special case where time travel is limited to a single object returning to the past and interacting with itself, consistency constraints can be avoided if the dynamics is continuous and the object's state space satisfies a certain topological requirement: that all null-homotopic mappings from the state-space to itself have some fixed point. Where consistency constraints (...) do exist, no new physics is needed to enforce them. One needs only to accept certain global topological constraints as laws, something that is reasonable in any case. (shrink)

I assess the thesis that counterfactual asymmetries are explained by an asymmetry of the global entropy at the temporal boundaries of the universe, by developing a method of evaluating counterfactuals that includes, as a background assumption, the low entropy of the early universe. The resulting theory attempts to vindicate the common practice of holding the past mostly fixed under counterfactual supposition while at the same time allowing the counterfactual's antecedent to obtain by a natural physical development. Although the theory has (...) some success in evaluating a wide variety of ordinary counterfactuals, it fails as an explanation of counterfactual asymmetry. (shrink)

Book Review of Quantum measurement: Beyond paradox.

Book review of The Interpretation of Quantum Mechanics and the Measurement Process.