The Structure of Space and Time

直到20世纪世纪，物理学家们基本上都不太关注空间和时间的结构。物理学家大多数时候都对空间和时间的物理内容（即物质和场）的结构以及控制它们相互作用和演化的方程感兴趣。空间和时间本身被简单地看作是一个不变的背景，一个欧几里得已经知道如何描述的背景，不需要进一步的关注。随着相对论在世纪初的出现，这种情况发生了变化。根据广义相对论，时空与它的内容相互作用，它的结构是非欧几里得的。事实上，现代物理学对空间和时间的结构还有许多其他的影响，这些影响很少受到关注。我的书（空间和时间，和东西）将讨论以下想法：时间没有任何结构的想法，即时间只由本质上不相关的快照的集合组成的想法;只有现在存在的想法;物理上可能的一切都发生在空间和时间的某个地方的想法;空间和时间不是物理对象，而是物理事件之间的关系;属性只是结构化空间中的位置;一个人可以通过“空间化”物体的物理属性来免除数学物体的想法，一个空间和时间不包含最小尺寸的点和瞬间而是无限可分的想法，空间和时间的结构允许时间以一种完全一致和清晰的方式旅行，最后，反粒子只不过是在时间中旅行的粒子。事实上，我的书相当于对一个统一的主题，即空间和时间的结构进行了相当详细的研究。在每一章中，我都集中讨论物理学的一个不同特征，并提出这样的问题：对这个特征的最好的基本解释是什么？它对空间和时间的结构有什么影响？

Until the 20th century physicists by and large did not pay much attention to the structure of space and time. Physicists were for the most part interested in figuring out the structure of the physical contents of space and time, namely matter and fields, and the equations that govern their interaction and evolution. Space and time themselves were simply taken as an immutable background, one which Euclid already knew how to describe, and which did not require much further attention. With the advent of Relativity Theory in the early 20th Century this changed. According to General Relativity space-time interacts with its contents, and its structure is non-Euclidean. In fact, there are many other implications that modern physics has for the structure of space and time which have received less scrutiny. My book (Space and Time, and Stuff) will discuss the following ideas: the idea that time has no structure whatsoever, i.e. the idea that time consists of nothing but a collection of intrinsically unrelated snapshots; the idea that only the present exists; the idea that everything that is physically possible occurs somewhere in space and time; the idea that space and time are not physical objects but rather relations between physical events; the idea that properties are nothing but locations in structured spaces; the idea that one can dispense with mathematical objects by 'spatialising' the physical properties of objects, the idea that space and time do not contain minimal-sized points and instants but are infinitely divisible, the idea that the structure of space and time allows time travel in a perfectly consistent and clear manner, and, finally, the idea that anti-particles are nothing but particles that are traveling back in time. In fact, my book amounts to a fairly detailed investigation of a single unified topic, namely the structure of space and time. In each chapter I concentrate on a different feature of physics, and ask: what is the best fundamental account of this feature, and what consequences does this have for the structure of space and time?