Time to Conceive: a New Argument for the Possibility of Time Travel

<p>Ordinarily, philosophers arguing for the possibility of time travel restrict themselves to defending time travel against allegations of inconsistency and contradiction. These objections are usually based on particular theories about time and causality. I believe, however, that this way of arguing can be turned on its head. By using the conceivability thesis – that is, the thesis that if something is conceivable, then it is also possible – we can put forward a positive argument for the possibility of time travel, and then consider how this should inform our metaphysical views. I do this by assuming the truth of the conceivability thesis and then presenting a simple piece of time travel fiction. I argue for the conceivability of this story and, in doing so, attempt to show that the time travel journey it describes is logically possible. I then develop this argument by considering other more controversial cases of time travel. I make minor alterations to the original time travel story in order to show that there are a number of different kinds of time travel journeys (including cases of both forwards and backwards time travel) which are conceivable and, therefore, logically possible. Finally, I ask how the conceivability of different types of time travel should affect the metaphysical views we choose to adopt. I argue that since the conceivability of time travel entails the logical possibility of journeys to other times, any plausible theory of time must be able to accommodate such journeys. I also explain how the conceivability of time travel entails the logical possibility of two particularly unusual cases of causation. I argue that the conceivability of instantaneous time travel entails the logical possibility of causation at a distance, and that the conceivability of backwards time travel entails the logical possibility of backwards causation. Any plausible theory of causation must therefore be able to account for the possibility of these two types of causation. I consider one particular theory of causation which does not (namely, that put forward by D.H. Mellor), and then attempt to establish where it goes wrong.</p>

Time to Conceive: a New Argument for the Possibility of Time Travel

<p>Ordinarily, philosophers arguing for the possibility of time travel restrict themselves to defending time travel against allegations of inconsistency and contradiction. These objections are usually based on particular theories about time and causality. I believe, however, that this way of arguing can be turned on its head. By using the conceivability thesis – that is, the thesis that if something is conceivable, then it is also possible – we can put forward a positive argument for the possibility of time travel, and then consider how this should inform our metaphysical views. I do this by assuming the truth of the conceivability thesis and then presenting a simple piece of time travel fiction. I argue for the conceivability of this story and, in doing so, attempt to show that the time travel journey it describes is logically possible. I then develop this argument by considering other more controversial cases of time travel. I make minor alterations to the original time travel story in order to show that there are a number of different kinds of time travel journeys (including cases of both forwards and backwards time travel) which are conceivable and, therefore, logically possible. Finally, I ask how the conceivability of different types of time travel should affect the metaphysical views we choose to adopt. I argue that since the conceivability of time travel entails the logical possibility of journeys to other times, any plausible theory of time must be able to accommodate such journeys. I also explain how the conceivability of time travel entails the logical possibility of two particularly unusual cases of causation. I argue that the conceivability of instantaneous time travel entails the logical possibility of causation at a distance, and that the conceivability of backwards time travel entails the logical possibility of backwards causation. Any plausible theory of causation must therefore be able to account for the possibility of these two types of causation. I consider one particular theory of causation which does not (namely, that put forward by D.H. Mellor), and then attempt to establish where it goes wrong.</p>

Kant and the Possibility of Transcendental Freedom

What does Kant claim to have shown in the Resolution of the Third Antinomy (RTA)? A recent publication by Bernd Ludwig shows the shortcomings of a fairly broad interpretative consensus around the claim that all that is at stake in the RTA is the mode of logical possibility. I argue that there is a lack of clarity as to what logical possibility, and that the real possibility of transcendental freedom (TF) is examined in much of the RTA. Ludwig’s own proposal that Kant shows the real possibility of TF however faces major problems. I formulate an alternative proposal that pays due attention to the claim of the antinomy’s thesis, the evolution of the argument of the RTA, and Kant’s later textual references to it. This also deals with the thorny issue of the relation between practical and TF.

Changing, Annulling and Otherwising the Past

Despite a growing number of models argument for the logical possibility of changing the past there continues to be resistance to and confusion surrounding the possibility of changing the past. In this paper I shall attempt to mitigate the resistance and alleviate at least some of the confusion by distinguishing changing the past from what Richard Hanley calls ‘annulling’ the past and distinguishing both from what I shall call ‘otherwising’ the past.

Punishment the Easy Way

Some argue against coercive preventive measures on the grounds that they amount to cloaked forms of punishment. Others offer a qualified defence of such measures on the grounds that such measures have substantively different goals and purposes from punishment. Focusing on the case of civil preventive injunctions, I clear the ground and provide reasons for a third logical possibility: that coercive preventive measures are relevantly similar to punishment, but this does not itself give us a reason to oppose them. ‘Punishment’ has a great deal of rhetorical force, and it thereby distracts us from the justificatory work that we need to do to specify proper restrictions on the state’s coercive powers. Whereas many commentators have proposed that legal theory provides grounds for challenging civil preventive orders, I argue for the opposite view. If we understand properly the function of civil preventive orders, we will endorse them at least in principle, and will come to rethink some central ideas in the grounding of the criminal justice processes.

Wittgenstein on 'Imaginability' as a Criterion for Logical Possibility

Throughout his whole work, Wittgenstein seizes on a distinction between logical and physical possibility, and impossibility. Despite this continuity and although, Wittgenstein brings in this distinction in various contexts and from different vantage points, he often solely brushes over it without elaborating in detail. In the so-called Big Typescript, however, he dedicates himself not only to the distinction between logical and physical possibility but also to the distinction between logical possibility and impossibility in particular investigations. In the course of these investigations, another aspect arises and is tossed and turned repeatedly by Wittgenstein – namely, the place of “imaginability” in these considerations. On the basis of three focussed chapters in the Big Typescript, I argue that “imaginability” as an utterance of the form “being able to imagine ‘what it would be like’” can be allocated the place of a criterion for logical possibility. To this end, I will first outline the chapters 96., 27. and 26. in one section each. Although in these chapters, Wittgenstein only indicates rather than claiming explicitly “imaginability” to be a criterion for logical possibility, I will discuss in the last section how this conclusion can be drawn by combining the results of the previous sections.

On the Logic of Being and Wigner's Astonishment Regarding the Applicability of Mathematics

The Nobel Prize winning Physicist, Eugene Wigner, famously posed a powerful challenge (1960) by asking why is mathematics so effective, especially in the physical sciences. It is possible that the reason for the effectiveness of mathematics is not because mathematics is in any way causative, but instead because mathematics studies the structure of logical possibility and constraint. When plugged into a possible world, mathematics gives us the tools to analyze the logically possible outcomes. Therefore, when a possible world that is expressed mathematically sufficiently aligns with reality, mathematics becomes effective at expressing relationships and outcomes.

Standing

This chapter introduces the key notions of moral standing and moral status, and notes the logical possibility that different individuals might have a higher or a lower status. It then turns to questions concerning the basis for having any kind of moral standing at all. A very common proposal is that sentience—the ability to feel pleasure and pain—is both necessary and sufficient for standing, but the author argues that an equally important idea (perhaps more important) is that of agency, having preferences about how things should go as well as the ability to act on those preferences. The chapter concludes with a brief discussion of the connection between having standing and having a welfare (being such that things can be better or worse for you).

The Logical Possibility of Halting Oracles

Halting oracles are often used in discussions of computability. This letter discusses whether or not such oracles are logically possible or if the idea itself contains internal contradictions.

Perception, epistemic issues in

We learn about the world through our five senses: by seeing, hearing, smelling, tasting and feeling. Sense perception is a primary means by which we acquire knowledge of contingent matters of fact. We can also acquire such knowledge by, for instance, conscious reasoning and through the written and spoken testimony of others; but knowledge so acquired is derivative, in that it must be based, ultimately, on knowledge arrived at in more primary ways, such as by sense perception. We can perceive something without acquiring any knowledge about it; for knowledge requires belief, and we can perceive something without having any beliefs about it. Viewing any but the most simple visual scenes we see many things we form no beliefs about. However, when we perceive something, we are acquainted with it by its sensorially appearing (looking, sounding, smelling and so on) some way to us. For we see something if and only if it looks some way to us, hear something if and only if it sounds some way to us, and so on. When, based on how they appear, we form true beliefs about things we perceive, the beliefs sometimes count as knowledge. Often the way something appears is the way it is. The red, round tomato looks red and round; the sour milk tastes sour. But the senses are fallible. Sometimes the way something appears is different from the way it is. Appearances can fail to match reality, as happens to various extents in cases of illusion. There are, for instance, optical illusions (straight sticks look bent at the water line) and psychological ones (despite being exactly the same length, the Müller-Lyer arrows drawings look different in length). In such cases, looks are misleading. The ever-present logical possibility of illusion makes beliefs acquired by perception fallible: there is no absolute guarantee that they are true. But that does not prevent them from sometimes counting as knowledge – albeit fallible knowledge. Recognitional abilities enable us to obtain knowledge about things from how they perceptually appear. Sense perception thus acquaints us with things in a way that contributes to positioning us to acquire knowledge about them. The central epistemic issues about sense perception concern its role in so positioning us.