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

2021 ◽  
Author(s):  
◽  
Daniel Burkett
Keyword(s):  
Time Travel ◽  
Logical Possibility ◽  
Positive Argument ◽  
Different Types ◽  
Backwards Causation ◽  
Travel Fiction ◽  
Original Time ◽  
Plausible Theory

<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>

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

2021 ◽  
Author(s):  
◽  
Daniel Burkett
Keyword(s):  
Time Travel ◽  
Logical Possibility ◽  
Positive Argument ◽  
Different Types ◽  
Backwards Causation ◽  
Travel Fiction ◽  
Original Time ◽  
Plausible Theory

<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>

The Bootstrapping Paradox

Time Travel ◽  
2020 ◽  
pp. 59-65
Author(s):  
Nikk Effingham
Keyword(s):  
Time Travel ◽  
Time Machine ◽  
Different Types

Bootstrapped things are things which are, at least partially, responsible for their own existence. For instance, a bootstrapped object might be someone who was their own mother whilst bootstrapped knowledge might exist because someone uses a time machine to go back in time and tell themselves how to make that time machine. The Bootstrapping Paradox is this: time travel is possible; were time travel possible, bootstrapped entities would be possible; such entities are impossible. This chapter investigates the different types of bootstrapped entity (objects, information, and causal loops). It then argues that you can avoid the paradox by denying that time travel necessitates bootstrapped objects and, more importantly, that there are also no good reasons to think bootstrapped entities are impossible.

Defending Backwards Causation1

1992 ◽  
Vol 22 (4) ◽  
pp. 429-443 ◽  
Author(s):  
Bryson Brown
Keyword(s):  
Science Fiction ◽  
Time Travel ◽  
Kurt Vonnegut ◽  
Backwards Causation ◽  
Ray Bradbury

Whether we’re reading H.G. Wells, Robert Heinlein, Ray Bradbury, or Kurt Vonnegut, time travel is a wonderful narrative trick, freeing a story from the normal ‘one damn thing after another’ progression of time. But many philosophers claim it can never be more than that because backwards causation in general, and time travel in particular, are logically impossible.In this paper I examine one type of argument commonly given for this disappointing conclusion: the time travel paradoxes. Happily for science fiction fans, these arguments fall far short of showing what they are intended to show. Why they fail can be better understood in the light of an analogy between these arguments and some arguments libertarians offer against determinism.

scholarly journals Does Lewis’ Theory of Causation Permit Time Travel?

Philosophies ◽  
2021 ◽  
Vol 6 (4) ◽  
pp. 94
Author(s):  
Phil Dowe
Keyword(s):  
20Th Century ◽  
David Lewis ◽  
Time Travel ◽  
Backwards Causation ◽  
Influential Theory

David Lewis aimed to give an account of causation, and in particular, a semantics for the counterfactuals to which his account appeals, that is compatible with backwards causation and time travel. I will argue that he failed, but not for the reasons that have been offered to date, specifically by Collins, Hall and Paul and by Wasserman. This is significant not the least because Lewis’ theory of causation was the most influential theory over the last quarter of the 20th century; and moreover, Lewis’ spirited defence of time travel in the 1970s has shaped philosophers’ approach to time travel to this day.

Origin and Diversity of Marine Larvae

2018 ◽  
Keyword(s):  
Life Cycle ◽  
Filter Feeding ◽  
Ecological Variation ◽  
Different Types ◽  
Marine Larvae ◽  
Planktotrophic Larvae ◽  
Plausible Theory

The origin of larvae has been much discussed, but the most plausible theory is the “terminal addition theory,” which proposes that the larvae originated when a benthic stage was added to the ancestral holoplanktonic life cycle, with the planktonic stage retained as the larva. Marine larvae show an astonishing morphological and ecological variation. Planktotrophic larvae are found in many smaller or larger lineages, and characteristic types—such as the trochophore of many annelids and molluscs, the cyphonautes of some bryozoans, the actinotrocha of most phoronids, the pluteus larvae of most echinoderms, and the tornaria of some enteropneusts—are familiar members of the plankton. These larvae show different types of ciliary filter feeding: trochophores have downstream-collecting, cyphonautes and actinotrocha have ciliary-sieving, and pluteus and actiunotrocha have upstream-collecting feeding. Crustacean larvae show a variety of feeding mechanisms. Lecithotrophic larvae are found in all phyla. A panorama of marine larvae is presented.

The extinction time of a general birth and death process with catastrophes

1986 ◽  
Vol 23 (04) ◽  
pp. 851-858 ◽  
Author(s):  
P. J. Brockwell
Keyword(s):  
Laplace Transform ◽  
Size Distribution ◽  
Sufficient Conditions ◽  
Necessary And Sufficient Conditions ◽  
Death Process ◽  
Extinction Time ◽  
Birth And Death Process ◽  
Different Types ◽  
The Laplace Transform ◽  
Necessary And Sufficient

The Laplace transform of the extinction time is determined for a general birth and death process with arbitrary catastrophe rate and catastrophe size distribution. It is assumed only that the birth rates satisfyλ0= 0,λj&gt; 0 for eachj&gt; 0, and. Necessary and sufficient conditions for certain extinction of the population are derived. The results are applied to the linear birth and death process (λj=jλ, µj=jμ) with catastrophes of several different types.

Differentiating between different forms of moral obligations

2020 ◽  
Vol 43 ◽  
Author(s):  
Rajen A. Anderson ◽  
Benjamin C. Ruisch ◽  
David A. Pizarro
Keyword(s):  
Moral Character ◽  
Moral Obligations ◽  
Different Types

Abstract We argue that Tomasello's account overlooks important psychological distinctions between how humans judge different types of moral obligations, such as prescriptive obligations (i.e., what one should do) and proscriptive obligations (i.e., what one should not do). Specifically, evaluating these different types of obligations rests on different psychological inputs and has distinct downstream consequences for judgments of moral character.

Ultrastructural Investigations of the Contractile Filaments of Amoebae

1974 ◽  
Vol 32 ◽  
pp. 188-189
Author(s):  
P.L. Moore
Keyword(s):  
Cytoplasmic Streaming ◽  
Three Dimensional ◽  
Freeze Fracture ◽  
Amoeboid Movement ◽  
Different Types ◽  
Chemical Conditions ◽  
Complete Interpretation

Previous freeze fracture results on the intact giant, amoeba Chaos carolinensis indicated the presence of a fibrillar arrangement of filaments within the cytoplasm. A complete interpretation of the three dimensional ultrastructure of these structures, and their possible role in amoeboid movement was not possible, since comparable results could not be obtained with conventional fixation of intact amoebae. Progress in interpreting the freeze fracture images of amoebae required a more thorough understanding of the different types of filaments present in amoebae, and of the ways in which they could be organized while remaining functional.The recent development of a calcium sensitive, demembranated, amoeboid model of Chaos carolinensis has made it possible to achieve a better understanding of such functional arrangements of amoeboid filaments. In these models the motility of demembranated cytoplasm can be controlled in vitro, and the chemical conditions necessary for contractility, and cytoplasmic streaming can be investigated. It is clear from these studies that “fibrils” exist in amoeboid models, and that they are capable of contracting along their length under conditions similar to those which cause contraction in vertebrate muscles.

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