Posted on 07/05/2003 4:20:08 PM PDT by betty boop
Go get Feynman's lectures on physics, or some other book on QM (I like Baym's lectures, but they're out of print), work through the chapters on photon polarization and on angular momentum, and you can derive everything I wrote from first principles. I gave you the result of the experiment; but you won't understand it in any real sense until you've learned some elementary algebra of 2 X 2 and 3 X 3 matrices. It's not difficult math, but there's no substitute for it. A reluctance to do the necessary work to understand QM on your part does not constitute argument from authority on my part.
I'll read it with American relish, though. Hope you're having a great time with the Danes, is it?
The American 'Rat (brown or whatever color).
I wasn't trying to assert any superiority of analog, or deny that there can be a conversion. The issue I was addressing was performance. For any given transistor speed, an analog to analog transform is faster than any transform that requires two conversions plus computation.
Plus, considering neurons simply as digital processors ignores the probability that their chemical environment may play key roles in computation. All this can have digital equivalents, but I was addressing the performance issue of designing a brain with a 100 hz clock.
Absolutely. The real bottleneck for silicon simulation of such systems is that cache coherence requirements and core latency massively degrade the actual performance. It is the nature of the algorithm space. So rather than building massively parallel silicon to do it, we single-thread it and run it at very high speeds to maximize real-world throughput because that is the easiest way to make it scale on silicon. The brain may process at very slow speeds, but the massive parallelism is such that current processors still can't simulate that number of slow processes in real-time.
This particular problem space underscores just how slow the main memory is on our computers and how narrow the bandwidth is to the actual processors. I've been involved in some research on elegantly scaling that domain to multiple processor systems so that the you actually get a net increase in scalability (most naive attempts will actually make these run SLOWER with multiple processors due to the memory problems mentioned above).
Latency is the big killer, but cache coherence is also a bit of a problem. The resource contention is so pervasive and fine-grained when having multiple processors simulating a vast number of parallel processes for this algorithm space that the processors are constantly stepping on each others cache. The way around this is by artificially partitioning the data space (not trivial) and using low-level process management APIs to tweak scheduling and affinity, but even that is a clever balancing act so that the cost of IPC doesn't kill the benefit of much better cache performance.
The nuisance of all of this is that making the code scale well on SMP or ccNUMA silicon makes the size of the codebase 2+ times larger versus a vanilla implementation and makes code tweaking much more tedious. The speed improvement is very significant though.
Which great physicist said he doesn't understand QM?
Dear Hank, I do apologize if I have offended you in any way.
I hope I will not be compounding the original "sin" for which I have just apologized by pointing to the source of the exasperation and sheer frustration I have in trying to have a conversation with you. The fact is, as I perceive it, that it simply doesn't matter what the topic under discussion is; inevitably, you make your correspondent the subject of the debate.
The above italics indicates a case in point.
In truth, "my" truth has been "revealed" to me -- by logic, reason, experience; by engagement in the social world; by my reading of the literature and history of mankind; by the contemplation of art; by trying to absorb as much as possible the diversified insights of the various disciplines of human knowledge; by great philosophy, especially that of classical Greece; by participating in and contemplating the glorious beauty of Nature; and by Holy Scripture.
At the end of the day, to the extent that I have to formalize the results of these various lines of inquiry into life and its meaning, so as to become a wise and just moral agent (that's a work-in-progress) I -- and I alone -- am responsible for what I believe. And I am grateful for that "inalienable" responsibility, which reason and free will confer on me.
Worse yet, I don't think it has a clock (I could be wrong, but I don't think so). Imagine designing a logical device with a high degree of interconnectivity and no clocking.
Good grief. If those who go out of their way to offend cannot, certainly nothing you said, which I know would never be inteded to that end, is going to offend me.
But, if you are sincere, you might answer one question. What is consciousness?
(For example, you have suggested that consciousness might be attributed to the entire universe or reality. I am interested if you mean the same thing by the word consciousness as I mean when I say, "when I am asleep, I am not conscious, when I awake again, I am.")
Hank
RWP, my heart goes out to you, as to one who has witnessed the devastation of Alzheimers in persons close to you. You have felt their horror (experienced in relatively rare moments of partial lucidity) as your own. In a certain way, that seems to open up a wider sphere for consciousness than perhaps we are accustomed to assume -- a meaning of consciousness in the sense of something that can be shared, as verified by strong emotional reactions (how I hate to use that word in this context) rooted in compassion and love.*
There is no "language" to express this sort of thing in the sciences today. And yet experiences like this are so much a part of human existence, of what it means to be human.
I really need some time to think through the issues you raise, which are inspirational for me. It might take me a while, and I'll probably post whatever I come up with as a separate thread, in due course. I'll ping you when the time comes.
Thank you so much, Professor, for writing.
Jean
*I've recently read about experiments conducted in regard to "induction effects" of consciousness, which suggest that there's more to consciousness than the sense of discrete self.
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