The philosophy of time travel pdf download

Report this app Download links do not work There is a new version Others. Download File. Download File Now. Related apps. August 23, at pm. Leave a Reply Cancel reply Your email address will not be published. Leave this field empty. This website uses cookies to improve your experience.

We'll assume you're ok with this, but you can opt-out if you wish. The moving spotlight is an intuitively appealing way to capture the central idea behind the Dynamic Theory, but in the end, it is just a metaphor. What the metaphor represents is the idea that A-properties like being future , being present , and being past are objective and metaphysically significant properties of times, events, and things.

Also, the metaphor of the moving spotlight represents the fact that, according to the Dynamic Theory, each time undergoes a somewhat peculiar but inexorable process, sometimes called temporal becoming. It goes from being in the distant future to the near future, has a brief moment of glory in the present, and then recedes forever further and further into the past.

Despite its being intuitively appealing especially for Static Theorists, who see it as a caricature of the Dynamic Theory , the moving spotlight metaphor has a major drawback, according to some proponents of the Dynamic Theory: it encourages us to think of time as a fourth dimension, akin to the dimensions of space. Above we mentioned that a metaphor sometimes used to characterize the Dynamic Theory is that of a moving spotlight that slides along the temporal dimension and that is such that only objects within the spotlight exist.

A similar sort of metaphor can also be used to characterize the Moving Spotlight Theory, which is an interesting hybrid of the Static Theory and the Dynamic Theory. Like the Static Theory, the Moving Spotlight Theory incorporates the idea of spacetime as a unified manifold, with objects spread out along the temporal dimension in virtue of having different temporal parts at different times, and with past, present, and future parts of the manifold all equally real.

But like the Dynamic Theory, it incorporates the thesis that A-properties are objective and irreducible properties, as well as the idea that time genuinely passes. The metaphor that characterizes the Moving Spotlight Theory is one on which there is a moving spotlight that slides along the temporal dimension and that is such that only things that are within the spotlight are present but things that are outside the spotlight still exist.

Thus the Moving Spotlight Theory is an example of an eternalist A-theory that subscribes to the dynamic thesis. Unlike presentist or growing block theories, spotlighters deny that any objects come into or out of existence. Unlike the B-theories, however, spotlighters think that there is an important kind of change that cannot be described just as mere variation in a spacetime manifold. Spotlighters think instead that there is a spacetime manifold, but one particular region of the manifold is objectively distinguished—the present.

And this distinction is only temporary—facts about which region of spacetime count as the present change over time. For example, right now a region of is distinguished as present. But in a year, a region of will enjoy this honor.

Just as there are different understandings of presentism and eternalism, there are different versions of the moving spotlight theory. Some versions think that even though the present is distinguished, there is still an important sense in which the past and future are concrete. Other versions like Cameron treat the spotlight theory more like a variant of presentism—past and future objects still exist, but their intrinsic properties are radically unlike those of present objects.

Fragmentalists see Fine think that there is a spacetime manifold but that every point in the manifold has its own type of objective presentness, which defines a past and future relative to the point. Why be a spotlighter?

Advocates think it combines some of the best features of eternalism while still making sense of how we seem to perceive a world of substantive passage. It also inherits some of the counterintuitive consequences of eternalism i. We are all familiar with time travel stories, and there are few among us who have not imagined traveling back in time to experience some particular period or meet some notable person from the past.

But is time travel even possible? One question that is relevant here is whether time travel is permitted by the prevailing laws of nature. This is presumably a matter of empirical science or perhaps the correct philosophical interpretation of our best theories from the empirical sciences. But a further question, and one that falls squarely under the heading of philosophy, is whether time travel is permitted by the laws of logic and metaphysics.

For it has been argued that various absurdities follow from the supposition that time travel is logically and metaphysically possible. Here is an example of such an argument:. Another argument that might be raised against the possibility of time travel depends on the claim that presentism is true.

For if presentism is true, then neither past nor future objects exist. And in that case, it is hard to see how anyone could travel to the past or the future. A third argument, against the possibility of time travel to the past, has to do with the claim that backward causation is impossible. For if there can be no backward causation, then it is not possible that, for example, your pushing the button in your time machine in can cause your appearance, seemingly out of nowhere, in, say, And yet it seems that any story about time travel to the past would have to include such backward causation, or else it would not really be a story about time travel.

Despite the existence of these and other arguments against the possibility of time travel, there may also be problems associated with the claim that time travel is not possible. For one thing, many scientists and philosophers believe that the actual laws of physics are in fact compatible with time travel. And for another thing, as we mentioned at the beginning of this section, we often think about time travel stories; but when we do so, those thoughts do not have the characteristic, glitchy feeling that is normally associated with considering an impossible story.

To get a sense of the relevant glitchy feeling, consider this story: Once upon a time there was a young girl, and two plus two was equal to five. One task facing the philosopher who claims that time travel is impossible, then, is to explain the existence of a large number of well-known stories that appear to be specifically about time travel, and that do not cause any particular cognitive dissonance.

Our best physical theories have often had implications for the nature of time, and by and large, it is assumed that philosophers working on time need to be sensitive to the claims of contemporary physics. Another example mentioned above was the worry that the A-theory conflicted with special relativity. The latter has proved especially influential in contemporary metaphysics of time and so deserves some further discussion. According to standard presentations of special relativity, there is no fact of the matter as to whether two spatially separated events happen at the same time.

This principle, which is known as the relativity of simultaneity , creates serious difficulty for the A-theory in general and for presentism in particular. After all, it follows from the relativity of simultaneity that there is no fact of the matter as to what is present, and according to any A-theory there is an important distinction between what is present and what is merely past or future.

According to presentism, that distinction is one of existence—only what is present exists. A different way of describing the relativity of simultaneity involves the combination of two claims:. This way of putting the relativity of simultaneity requires a new bit of technical jargon: the notion of a reference frame. For our purposes, a reference frame is nothing more than a coordinate system that is used to identify the same point in space at different times.

Someone on a steadily moving train, for instance, will naturally use a reference frame that is different from someone who is standing on the station platform, since it is natural for the person on the train to think of themselves as stationary, while for the person on the platform it seems obvious that they are moving.

The reason why it is worth introducing this bit of jargon is that once you present the relativity of simultaneity as the combination of claims i and ii , you can also note that the motivation for claim i is importantly different from the motivation for claim ii. The motivation for i is a series of empirical results at the end of the nineteenth and beginning of the twentieth century, including, most famously, the Michelson-Morley experiment. No one should deny this part of the relativity of simultaneity.

This means that presentists and other A-theorists have a way of avoiding the worry from relativity without any conflict with empirical results—they can reject whatever extra-empirical principle motivates ii. Whether you think the costs associated with this move are worth paying will depend on your degree of commitment to the A-theory, what exactly you think of the relevant extra-empirical principle supporting ii , and whether that principle plays an important role elsewhere in physics.

It is often said that philosophers should defer to physics with respect to what the latter says about time. But the interaction between the A-theory and special relativity illustrates one way in which that claim is more complicated than it first appears. Must philosophers respect both the empirical and the extra-empirical aspects of our best physical theories? Or is it sufficient that they respect the former? Another way in which this assumption is complicated is that different physical theories often seem to imply different things about the nature of time.

Consider, for instance, the fact that in general relativity there is sometimes though not always! Two additional questions about the nature of time that have been especially influenced by contemporary physics have to do with the arrow of time and the extent to which time itself might be emergent. To motivate the first question, start from the observation that the order in which events happen in time seems to matter a great deal.

There seems to be an important difference, for instance between a train traveling from Boston to Providence and a train traveling from Providence to Boston. This is because, even though both of these sequences may be constituted by the very same events, those events are in a different order in each sequence. In the former sequence the train being in Boston happens earlier than the train being in Providence. In the latter, the train being in Boston happens later.

These straightforward observations show that we experience time as having a direction. But is the arrow of time a fundamental feature of the world? Or can it be reduced to some other feature, thus simplifying our metaphysics as a whole? Imagine the history of the universe as a long timeline, but with no indication of which end of the time line represents the first moment of time and which end represents the last moment. It follows from certain interpretations of statistical mechanics that there is a physical quantity, the entropy of the universe, that will be relatively low at one end of the timeline and relatively high at the other end and will always increase as you move from the former end of the timeline to the latter.

More carefully, the entropy will almost always increase or at least stay constant. The thought, then, is that we might be able to reduce the arrow of time to this entropy gradient. Earlier moments of time are just moments of time when the entropy of the universe is lower. This way of eliminating the arrow of time from the fundamental level is promising, but has at least some unintuitive consequences.

For instance, it seems natural to think that entropy could have decreased over time, instead of increasing over time as it actually does. But given the reduction described above, it is not in fact possible for entropy to decrease over time. This question has become especially pressing as philosophers of physics have turned their attention to theories of quantum gravity in which there does not seem to be anything like temporal structure at the fundamental level.

Work in this area is nascent, but some of the questions of interest include: Does quantum gravity eliminate time entirely or does it merely make time a non-fundamental feature of the world?

What would it mean for something temporal to be grounded in something atemporal and what sort of grounding relation would be involved? What is the distinction between causal structure especially the causal structure in causal set theory—one approach to quantum gravity and temporal structure?

And how can a theory that eliminates time entirely be empirically confirmed or disconfirmed? A final important question concerns how considerations about the nature of time ought to impact the ways that we reason about time.

For example, if it turns out that a B-theory is true, and there is no metaphysically important difference between the past and future, then should we adopt a more neutral attitude about events in our personal past and future? Epicurean philosopher Lucretius famously suggested that if there is no substantive difference between the times in the past before we came to exist and the times in the future after we die, we should care much less about the deprivation that death will bring.

Still other A-theorists argue that while there is an important metaphysical distinction between the past and future, the distinction has no normative importance. He had been raised in a pious and orthodox Protestant home, but gradually moved away from this tradition The aim of all my writings centers in Philosophy the endeavor to build up a sound and objective tenable philosophy, one that would be as science,….

Science and Hebrew tradition; essays by Thomas Henry Huxley PDF book EXCEPT: for more than a thousand years, the great majority of the most highly civilized and instructed nations in the world have confidently believed and passionately maintained that certain writings, which they entitle sacred, occupy a unique position in literature, in that they possess an authority, different in kind, and immeasurably superior in weight, to that of all other books.

Age after age, they have held it to be an indisputable truth that whoever may be the ostensible writers of the Jewish, Christian, and Mahometan scriptures, God Himself is their real author; and, since their conception of the…. Born in Montgomery, Alabama to a Jewish family, he was forced by poverty to leave school at the age of nine to find employment.

He read avidly, becoming self-educated. Lewis developed his ideas from reading, among others, Robert G. Ingersoll, whose published works made him aware of Thomas Paine. He was first impressed by the idea to become an atheist after…. Published: Jul Downloads: Pages: Patriarchs and Prophets Ellen G. Published: May Downloads: 51 Pages: Published: May Downloads: Pages: Published: Jan Downloads: 94 Pages: Published: Nov Downloads: Pages: A Pictorial Key to the Tarot A.

Published: Oct Downloads: Pages: Published: Apr Downloads: Pages: Published: Mar Downloads: Pages: Page 1 2