Monday, September 26, 2022

I want to believe...

How often one now encounters the terms "skeptical" or "skepticism" used, or rather misused, to refer not to the systematic application of doubt, but rather to positive belief in some idea which has simply come to replace a previous belief in something else!

One cannot be said to be skeptical in the proper sense of the word while demonstrating a robust faith in the reality or truth of any given proposition. 

Islands of time

(For the previous post) ... These instants, the moment-islands from which the experience of time is derived, are known by another name - "Nows" - and it is always now. There is never any other time for us. This aspect of embodied cognition is practically impossible to deny. From the standpoint of experience this is as close to an observational fact as anything. Everyone's "now", no matter the relation between observers, is essentially unchanging as a structure. The only things that seem to change are the contents within that structure. Everything that can be known, felt, or understood exists as a part of some "now" which is a possible reality for some entity or cognitive agent. 

Some "nows" also exist within other "nows", while remaining complete structures in themselves.

Nothing like this occurs, as far as presently can be known, for matter in general; only for a vanishingly small proportion which happens to persist in a highly ordered state, which we are apt to refer to as a brain or the central nervous system, or more specifically the . Even the awareness of the existence of those features and the names given to them must occur within the reality of some perceptible instant, or as is more often the case, across a multitude of "nows".

If we allow for the existence of nothing else, we must at least allow for the reality of each instant as a concrete existence, neither "coming into" being nor "passing away", because if they partake of any reality whatever - at any time, that is - they cannot suddenly spring into existence ex nihilo and promptly vanish into the same nothing! Where would they go, and where would they have come from? Nature is everything, and nothing exists outside of it, so if the all the instants are not real in some permanent or timeless sense then nothing can be real in any sense whatsoever.  

"It is utterly beyond our power to measure the changes of things by time. Quite the contrary, time is an abstraction, at which we arrive by means of the changes of things."      

             - Ernst Mach, quoted from The End of Time by Julian Barbour, Oxford University Press, 1999

It is often said that a great work of art or music is "timeless". But what if everything, the whole of nature itself, surely the greatest work of art known to anyone, is literally timeless, possessed of a permanence which only ever appears to us in fragmentary form? This is in fact a very old idea, going back at least as far as the Eleatic philosopher Parmenides (6th-5th century BCE), who famously asserted that all change is mere illusion, and that behind the appearance of movement the entire universe is static. His sole surviving work, On Nature, a prose poem that exists today only in fragments, contains what is widely thought to be the first extant example of a philosophical argument. It is here that Parmenides lays out his case against the reality of change and our conventional notions of past, present and future:

"As yet a single way remains,
that it is; and along this path markers are there
very many, that What Is is ungenerated and deathless,
whole and uniform, and still and perfect;
but not ever was it, nor yet will it be, since it is now together
    entire,
single, continuous; for what birth will you seek of it?
How, whence increased? From not being I shall not allow you
to say or to think: for not to be said and not to be thought
is it that it is not. And indeed what need could have aroused it
later rather than before, beginning from nothing, to grow?
Thus it must either be altogether or not at all.
Nor ever from not being will the force of conviction allow
something to come to be beyond it: on account of this neither
    to be born
nor to die has Justice allowed it, having loosed its bonds,
but she holds it fast. And the decision about these matters lies
    in this:
it is or it is not; but it has in fact been decided, just as is necessary,
to leave the one unthought and nameless (for no true way is it),
and <it has been decided> that the one that it is indeed
    is genuine.
And how could What Is be hereafter? And how might it have been?
For if it was, it is not, nor ever it is going to be:
thus generation is extinguished and destruction unheard of."


(trans. John Palmer, from Parmenides and Presocratic Philosophy, Oxford University Press, 2009)

Despite countless attempts by subsequent philosophers to provide a definitive answer to this challenge, none have as yet been successful at resolving this fundamental contradiction between the competing demands of existence for the same object(s) at differing times. 

So perhaps reality really is, after all, just as the French would have it: "plus ça change, plus c'est la même chose!"

Note: I am indebtted to Julian Barbour both for the terminology of "nows" and for the underlying physical argument. The case he lays out in the work cited is a compelling one, and I confess to having been greatly impressed by the possibility that time is not a fundamental physical constituent of the universe. To be sure there are a number of outstanding difficulties with this admittedly bold proposal - something I hope to discuss in subsequent entries - but it is striking how well the idea seems to match up to the available evidence, quite contrary to intuition.   

Sunday, September 18, 2022

Caught in the net

How to square the fundamental and necessary unity of nature against the asymptotic chasm, that insuperable gulf that lies between one mind and the next? Not even the distances between galaxies, those inconceivably vast reaches of space stretching out of the very depths of time, approach the infinite remoteness of what can never be felt by anyone or anything beyond the perceiver who experiences just those things, and in just that particular way.    

"Even in the sphere of sensation individuals are probably different enough. Comparative study of the simplest conceptual elements show a wider divergence still. And when it comes to general theories and emotional attitudes towards life, it is indeed time to say with Thackeray, 'My friend, two different universes walk about under your hat and under mine.'"

       - William James, "The Function of Cognition", first published in Mind, vol. X (1885)

Yet the possibility of solipsism, so flattering to the intellect, contradicts itself from the outset: Both you and I cannot simultaneously claim the other does not exist and hold out much hope that either of us is correct. 

All the more perplexing the ineffable remoteness of one moment to the next within the same span of life, despite the contiguous nature of their presentation. The present ever commencing its stately departure leaves behind a swirling wake in the backwaters of memory, forever erasing the composure of the scene once beheld. The child of my past is but a stranger to me now, and my future self not yet a dim outline of shadow. Yet they were, and they will be... but where are they, precisely, now?  

Each moment within each mind an island of time emerging from a sea of dynamic possibility, strung together like glass beads on an invisible warp. Can a moment be made any less real by its passing, once having been made at all? 

Not even in dreams is there escape from the reflected glare of Indra's glistening net.

Saturday, September 10, 2022

Another friendly public service reminder

A neuron is not a transistor. 

A transistor is not a neuron.

A transistor is a solid-state semiconducting "sandwich" consisting of three adjacent regions of doped silicon (or germanium, historically) called the base, collector and emitter, respectively (or source, gate, and drain for FETs), enabling it to function as an electrical switch or signal amplifier by modulating the flow of current through the device using a smaller control current.

 
A electric current applied at the base (or gate) can effectively switch "on" or "off" the current flowing from collector to emitter (or source to drain as in the animation below); the basic principle on which digital logic circuits inside computers operate: 


A neuron, by contrast, is a nerve cell. It is a complex electrochemical system of biological origin having multiple dendrites and one or more branched axon terminals that can exist in relative states of excitation in response to specific messages from surrounding neurons, both by means of electrical impulses and through the influence of chemical neurotransmitters. 

 


A unique combination of these inputs typically results in a neuron increasing (or decreasing) its rate of firing in response to a broad array of shifting signal patterns arriving from multiple sources. Furthermore, there are many different types of neurons depending on their function and location in the nervous systems of living creatures:

 


In no way does a neuron function, either in isolation or in situ, as a standardized electrical switch or current amplifier analogous to those devices as they are commonly found in human-manufactured electronic circuits. 

Groups of neurons do not link together to form logic gates. They do not perform Boolean operations or work in pairs to form "flip-flops" (latches) or registers. There is no "machine code" for the human brain. It is not a Turing machine. There is no software consisting of "ones" or "zeros". In fact, there doesn't appear to be any software at all! It's all hardware, and it's analog, not digital. How it all works together to create the experience of life as we know it is still anybody's guess. It's a black box.   

Therefore, brains are not computers. And computers are not brains.   

Thank you for your attention. We now return to our regularly scheduled programming...