Quantum Quotes - page 5
Quantum mechanics is the most useful and powerful theory physicists have ever devised. Yet today, nearly 90 years after its formulation, disagreement about the meaning of the theory is stronger than ever. New interpretations appear every year. None ever disappear. ... The message from QBism is this: You needn't feel guilty about never getting nervous about this stuff. You were right not to be bothered. But for the sake of intellectual coherence, you had better reexamine what you wrongly may have thought you understood perfectly well about the nature of probability.
David Mermin
It was found [in the 1970s], unexpectedly and without anyone really having a concept for it, that the rules of perturbation theory can be changed in a way that makes relativistic quantum gravity inevitable rather than impossible. The change is made by replacing point particles by strings. Then Feynman graphs are replaced by Riemann surfaces, which are smooth - unlike the graphs, which have singularities at interaction vertices. The Riemann surfaces can degenerate to graphs in many different ways. In field theory, the interactions occur at the vertices of a Feynman graph. By contrast, in string theory, the interaction is encoded globally, in the topology of a Riemann surface, any small piece of which is like any other. This is reminiscent of how non-linearities are encoded globally in twistor theory.
Edward Witten
Replacing particles by strings is a naive-sounding step, from which many other things follow. In fact, replacing Feynman graphs by Riemann surfaces has numerous consequences: 1. It eliminates the infinities from the theory. ...2. It greatly reduces the number of possible theories. ...3. It gives the first hint that string theory will change our notions of spacetime. Just as in QCD, so also in gravity, many of the interesting questions cannot be answered in perturbation theory. In string theory, to understand the nature of the Big Bang, or the quantum fate of a black hole, or the nature of the vacuum state that determines the properties of the elementary particles, requires information beyond perturbation theory... Perturbation theory is not everything. It is just the way the [string] theory was discovered.
Edward Witten
Is the very mechanism for the universe to come into being meaningless or unworkable or both unless the universe is guaranteed to produce life, consciousness and observership somewhere and for some little time in its history-to-be? The quantum principle shows that there is a sense in which what the observer will do in the future defines what happens in the past-even in a past so remote that life did not then exist, and shows even more, that 'observership' is a prerequisite for any useful version of 'reality.
John Archibald Wheeler
I had the good fortune of having my first and only heart attack last January ... I call it good fortune because it taught me that there's a limited amount of time left and I better concentrate on one thing: How come existence? How come the quantum? Maybe those questions sound too philosophical, but maybe philosophy is too important to be left to the philosophers.
John Archibald Wheeler
We humans replace the bulk of both our "hardware” (e. g., our cells) and our "software” (e. g., our memories) many times in our life span. Nonetheless, we perceive ourselves as stable and permanent. Likewise, we perceive objects other than ourselves as permanent. Or rather, what we perceive as objects are those aspects of the world that display a certain permanence. For instance, when observing the ocean, we perceive the moving waves as objects because they display a certain permanence, even though the water itself is only bobbing up and down. Similarly (...) we perceive only those aspects of the world that are fairly stable against quantum decoherence.
Max Tegmark
Even a statement very close to the periphery can be held true in the face of recalcitrant experience by pleading hallucination or by amending certain statements of the kind called logical laws. Conversely, by the same token, no statement is immune to revision. Revision even of the logical law of the excluded middle has been proposed as a means of simplifying quantum mechanics; and what difference is there in principle between such a shift and the shift whereby Kepler superseded Ptolemy, or Einstein Newton, or Darwin Aristotle?
Willard van Orman Quine
If people have personal conversations about very emotional matters in public, and people reveal parts of their body that were originally kept covered, and pornography is becoming semi-respectable, it makes you think the push for greater freedom and divesting yourself of inhibitions is a real human need. I'm 54, so I'm further back upon the road. We certainly did a fair amount of divesting ourselves of inhibitions, but there seems to have been a quantum leap in the last half a generation. Maybe we're destined to be freer, but it's taking odd forms, like showing your big gut to all the world and discussing the future of your marriage at a bus stop with 30 people listening in.
Martin Amis
The quantum theory, as it is now constituted, presents us with a very great challenge, if we are at all interested in such a venture, for in quantum physics there is no consistent notion at all of what the reality may be that underlies the universal constitution and structure of matter. Thus, if we try to use the prevailing world view based on the notions of particles, we discover that the 'particles' (such as electrons) can also manifest as waves, that they move discontinuously, that there are no laws at all that apply in detail to the actual movements of individual particles and that only statistical predictions can be made about large aggregates of such particles. If on the other hand we apply the world view in which the world is regarded as a continuous field, we find that this field must also be discontinuous, as well as particle-like, and that it is as undermined in its actual behaviour as is required in the particle view of relation as a whole.
David Bohm
In relativity, movement is continuous, causally determinate and well defined, while in quantum mechanics it is discontinuous, not causally determinate and not well defined. Each theory is committed to its own notions of essentially static and fragmentary modes of existence (relativity to that of separate events, connectable by signals, and quantum mechanics to a well-defined quantum state). One thus sees that a new kind of theory is needed which drops these basic commitments and at most recovers some essential features of the older theories as abstract forms derived from a deeper reality in which what prevails in unbroken wholeness.
David Bohm
