Year: 2022

NOT A CONTRADICTION. “Computers by their very nature are the most inflexible, desireless, rule-following of beasts. Fast though they may be, they are nonetheless the epitome of unconsciousness. How, then, can intelligent behavior be programmed? Isn't this the most blatant of contradictions in terms?” (Clue, this book makes the case that this is not true). https://lnkd.in/dmfn9qW View in LinkedIn

This image is deeply embedded in ancient Girona stonework. View in LinkedIn

FRAGMENT FROM NATURE continues from last weekend and concludes this weekend on an exceptional article by Professor Jeremy Butterfield on quantum issues including gravity and time. We are lucky to have great minds contemplating these marvelous issues, for the world becomes a different place after their illuminations. View in LinkedIn

THE THIRD LEG. “We barely mentioned something that everyday thought takes to be much more unproblematically real than space and time: namely, matter! Why matter comes to play second fiddle to space and time.” https://lnkd.in/dMm_YkR View in LinkedIn

GRAVITY IS THE PROBLEM. “Many of the conceptual issues surrounding the emergence of time, or the problem of time, are much the same, whether or not one considers matter. For example, as Kuchar (this volume) says, “matter is not the heart of the problem [of time in geometrodynamics]; it is gravity”. https://lnkd.in/dMm_YkR View in LinkedIn

MATTER AS A FIELD. “Some of the most distinctive characteristics of matter, at least as idealized by the mechanical philosophy of the seventeenth century—such as impenetrability and continuity— turn out to be only apparent; and others, such as massiveness, turn out to be shared with invisible fields that extend in ‘empty space’ arbitrarily far from their sources. Further, matter itself has come to be treated as a field, and this involves being represented mathematically by an assignment of a mathematical object—at its simplest: an item like a real number, or a vector, or a matrix—to each point of space or spacetime.” https://lnkd.in/dMm_YkR View in LinkedIn

FIELD LANGUAGE. “Thus, with the rise of classical field theory, culminating in general relativity, the field gradually became endowed with properties previously thought peculiar to matter. Thus the electromagnetic field was discovered to possess mechanical properties like momentum and angular momentum, and (after the advent of special relativity) mass-energy. The ‘action-at-a-distance’ of Newtonian gravity readily admits a translation into the language of fields; and, of course, the theory of general relativity was couched in such language from the outset.” https://lnkd.in/dMm_YkR View in LinkedIn

TRANSMOGRIFICATION. “Furthermore, this assimilation of matter to the concept of a field continued with quantum theory. Even elementary quantum theory has a formulation (wave mechanics) which can be thought of as a field theory. And this picture deepens with the advent of quantum field theory: here physical quantities describing matter are again represented by a field; albeit in a transmogrified form in which an operator (rather than a simple real number) is associated with each space, or space-time, point.” https://lnkd.in/dMm_YkR View in LinkedIn

THE CHRONOGEOMETRY OF REALITY. “In short, the effect has been for matter to now play second fiddle to space and time. As these field theories, both classical and quantum, are presented to us, their basic objects seem to be just spacetime points. All else—matter, fields, and even the metrical structure of spacetime, the ‘chronogeometry’ of the world—are represented as mathematical structures defined on these points; in particular, as just emphasised, physical quantities for matter and fields are represented by structures defined point by point.” https://lnkd.in/dMm_YkR View in LinkedIn

SPACETIME AS OBJECTS. “And so it is natural to presume that all these are to be construed as properties of (and relations between) points, or higher-order properties and relations. In short, we arrive at the doctrine now called ‘substantivalism’: that spacetime points are genuine objects, indeed are the basic objects of physical theory.” https://lnkd.in/dMm_YkR View in LinkedIn