The belief that "brains are computers" is widely held. (See, e.g., the Encyclopedia of Computational Neuroscience.) Timing devices challenge that belief in a concrete and practical way.
why brains are not computers
This page was originally published in 2007, was later amended, and continues to state chief principles in a useful way. Some later developments are listed ( ... ) below. All the pages on the site are listed in the ( ... ) Quad Net Site Map.
Essence of Timing Devices
1. The purpose of timing devices designs
Timing devices are proposed electronic components that can be assembled into networks. An individual timing device embodies essential activity of a neuron; and a network of timing devices operates an engineered organism like a brain operates an animal. Some timing devices in such a network drive muscle-like fibers while other timing devices are sensitive to external stimuli and act as sensors.
The image below is a design for an engineered organism that would dwell in a water environment and "follow" a source of sensation, e.g., a moving light. Each square box stands for a simple timing device. Sensory units produce signals that are "balanced" against each other and control muscle-like twitches in motor units so as to direct the engineered organism with respect to a source of stimulation, e.g., towards a light or a particular food-like molecule.
2. The primal timing device
The simplest timing device, called the primal timing device, is a point of origin for development. Additional pieces of hardware (e.g., various "projections") and functions are added stepwise to the primal timing device for more complex operations. A development path connects the primal timing device with the general Quad Nets model that is more powerful and that incorporates a suggested account of consciousness.
The primal timing device in Figure 1.a has a "response clock" shown in the form of a round clock dial. The response clock resembles a stopwatch used in a sports contest. It is controlled by two timing intervals: namely, δ, the responding period, and β, the refractory period. A timing interval is a period of time that governs the operations of a timing device and that is adjustable during operations. A timing interval or time period has a dimension of seconds, e.g., milliseconds.
Timing devices are interconnected by "projections." Timing devices are presently imaginary; in a supposed real device, a projection is a wire that conducts electricity or is "like" such a wire. A "projection from" extends out of a timing device and a "projection onto" attaches to a timing device through a "junction." A junction embodies the asymmetrical nature of a projection and resembles a synapse in a neuron. A projection from one timing device becomes a projection onto another timing device.
In operations, as shown in Figure 1.b, an input pulse through the projection onto at t=0 triggers the primal timing device and starts the response clock. After a passage of time equal to the responding period, at t=δ, the timing device produces a pulse through the projection from. The response clock continues to run until t=δ+β and then resets. During operations, the timing device is first in a ready condition, then a responding condition, then a refractory condition, and, finally, it returns to a ready condition. While the timing device is in the ready condition, the response clock is "stopped" at the start point and the ready condition is a state that continues until changed by an input pulse. While the timing device is in the responding condition or the refractory condition, a second input pulse has no effect.
3. Operational control shown in a "4-cycle" of primal timing devices
A 4-cycle made up of four primal timing devices. (Figure 2.a.) In the simplest form of the 4-cycle, all 4 timing devices have a common δ and β. During operations, each primal timing device produces pulses in a steady stream, called a pulse train, shown in Figure 2.b. The period between any two pulses in such a pulse train is τ=4δ. Operation of the 4-cycle requires that β<3δ. If β>3δ, a timing device will not have returned to the ready condition when the next input pulse arrives, which will, therefore, have no effect.
Suppose a 4-cycle is producing pulse trains while β<3δ. Then suppose that β is gradually increased until pulsing ceases as β passes upward through β=3δ. That is, a continuous variation in β causes a discontinuous change in the activity of the assembly. The activity of the 4-cycle is controlled by means of the ratio of β to δ. The control is in the nature of switch. In larger assemblies, small variations in timing intervals can cause an engineered organism to switch quickly between global modes of activity, e.g., like a switch from feeding to flight from danger. See § 5 of the Timing Devices paper, setting forth the design of a timing devices assembly called a "pulse period selector" that operates like a band-pass filter in electronics, where switching can be controlled by a small variation in a timing interval.
The 4-cycle is not closely similar to a brain design but it illustrates features of the Quad Nets model, which is more similar to brains. A gradual variation in β and/or δ operates on a longer time scale than the pulsing timing interval based on δ. It is like pressing on the accelerator in a car: the engine is turning over at 15-100 cycles per second (90-6000 rpm) while the variation caused by pressing on the accelerator is occurring at the rate of about 1 cycle per second. Quad Net systems typically operate on multiple interconnected time scales.
4. Timing devices networks are different from computers
Operations in computers, based on the division between hardware and software, are temporally more rigid than those in timing device assemblies. "On-the-fly" temporal variations are not inherent in computer operations but can only appear in results through high-level programming methods.
The lack of inherent temporal adjustments in computers is illustrated by an extract from Biophysics of Computation: Information Processing in Single Neurons (1999) by Christof Koch, at page 470:
"Brains differ in some rather obvious ways from present-day computers: memory and computation are not separated as they are in all of our current machines; the nervous system operates without any systemwide clock and is built from stochastic elements. Finally, developing as well as mature brains are constantly reprogramming themselves, up or down regulating synaptic weights, modulating the degree of adaptation, shifting the character and frequency of central pattern generators, changing the time constants of integration, and so on. Conceptually, this amounts to the input changing the transition function governing how the machine switches from one state to the next. Put differently, a nervous system will act like a machine that changes its instruction set as a function of its input."
Koch's statement is a confusing collection of temporal adjustments that have no inherent basis in a computer model. I do not understand "without any systemwide clock," since I possess at least one in my brain that controls my daily activities like sleep. ["Sleep" is incongruous with a computer model; the "eigen-phase" in Quad Net models (Quad Nets, § 2.c) suggests a reason for sleep, namely, so that neurons can "synchronize their clocks.")
In contrast to computers' inability to deal directly with time, levels of temporal adjustment in the Quad Nets model are organized by the inherent design. On the longest time scale, there are adjustments of junctions that correspond to "regulating synaptic weights." Operations can incorporate an inbuilt source of "circadian" or daily rhythms; as well as other rhythmic sources, like sources of musical beats and muscular movements. Inside the daily time scale is a "situational time scale," corresponding, e.g., to movements of a student from home to school to homeroom to math class to physical education to lunch to English class to band practice, etc. Each situation calls for a different distribution of blood flow (energy flow) into the various brain parts. A particular task in a situation calls for fixed signals that will change when the task changes. A shorter time scale involves variations in timing intervals that govern activities of a brain part, like the variations in β and/or δ that control the activities of the 4-cycle, described above. Finally, at the shortest time scale, are the intervals between pulses, e.g., τ=4δ in the 4-cycle.
All quantities involved in operations of timing devices, e.g. the timing intervals δ and β, are stated in terms of time and nothing else. Each timing device has its own individual timing intervals; and individual timing intervals can be separately varied, e.g., through sensory input (as in the "following" system, above). In contrast, devices used in computers ("finite state machines") have no separate timing controls and operations are governed by an external clock that dispatches data through "pipes." While timing variations are central in timing devices, such variations are of little or no significance in the general theory of computers; and incorporation of timing controls in computerized systems is by way of a software superstructure.
An input to a computer device (that is, a finite state machine) changes the state of the device; and the new state remains without change until another input. In contrast, an input to a timing device starts a sequence of changes that occur in accordance with the timing intervals.
Operations in timing device networks (and Quad Nets constructions), as illustrated in the 4-cycle, above, show an essential characteristic: a continuous variation in timing intervals causes a discontinuous change in operations. This is like the change that occurs when liquid water freezes as temperature passes continuously downward through 0º C. Such changes are called phase changes and they are studied in thermodynamics. The physical systems that are conformable to computer operations are studied in the physics of mechanics. (See, e.g., R. Penrose, The Emperor's New Mind, e.g., at 173 - "the Newtonian world is indeed computable.") Thermodynamics and mechanics are different branches of physics and involve different kinds of reasoning. Although some physicists contend that mechanics "comprehends" thermodynamics, my view is to the contrary. Only very special phase changes, e.g., those that occur "quasi-statically," can be described by mechanics. The "quasi-static process" is inadequate "for engineers who wish to see engines run, not creep." [C. Truesdell and S. Bharatha, The Concepts and Logic of Classical Thermodynamics as a Theory of Heat Engines etc. (1977) at xii.] In my opinion, the same inadequacy afflicts artifical intelligence that is based on mechanical foundations. My "thermal device models of brains" are an alternative to the "mechanical device models of brains" embodied in computers.
5. Networks of timing devices and Quad Net devices have advantages over computers in accounting for biological brains and human psychology.
I am unable to pursue the many possibilities suggested by these systems. However, the following propositions appear to me to be potentially fruitful in ways that (as far as I can see) are superior to computerized models.
The "4/4 Musical Meter Generator" shown in the adjacent image can generate any 4/4 musical meter within broad operating constraints. It can drive all kinds of muscles, include those that produce breathing, fingerings and tapping feet. No "computational system" is needed. The Generator (shown here as if "dissected" from a full brain) combines the more advanced Quad Nets system with the simpler Timing Devices system, but it is an operational design and potentially realizable. Timing devices make up the 4-cycle previously discussed that is at the top of the image and that provides the basic 4/4 beat (with timing adjustments available for each pulse in the cycle). Additional projections extend downward from the 4-cycle and operate according to the "equal-output rule" discussed in the Timing Devices paper, section 3: when a timing device with multiple projections from produces a pulse, it does so equally through all projections from that timing device.
- Timing Devices and Quad Nets imply a stepwise development path that starts by mimicking muscle-like activities of invertebrates and fishes and that leads toward modeling complex activities of higher animials and humans, guided by the principle of Shimmering Sensitivity (Quad Nets, § 3) that is directed towards consciousness and freedom.
- QN development has a central focus on quick switching between modes of activity, constructing means to accomplish speedy changes such as those involved in animal predation and athletic games, e.g., ping-pong. There is no need to "process information" through a "program" as required by computers.
- Music is universal in human cultures and has no existence other than in the brains of humans and some animals. Daniel J. Levitin's This Is Your Brain on Music / The Science of a Human Obsession (2006) is highly informative but presumes a computational model. Timing devices and Quad Nets devices provide a simpler and more direct approach.
Levitin writes (at p. 32):
"Although the areas of the brain that respond to individual pitches have been mapped, we have not yet been able to find the neurological basis for the encoding of pitch relations...These relations must be extracted by computational processes that remain poorly understood."
Timing device processes can generate pitch relations, but the processes are not computational. This principle is discussed in An Ear for Pythagorean Harmonics: Brain Models Built From Timing Devices (12/28/2009), a web page with a link to a full technical presentation (.pdf file - 460 kB). These advanced developments have grown out of the materials on this website for which there is an earlier version, titled An Ear for Pythagorean Harmonics: Mathematical Processing in Brain Models Built From "Timing Devices," a .pdf file, 212 kB.
The image below shows an early design of an Ear for Pythagorean harmonics. When the frequencies of the two input pulse trains are in a specified relation, e.g., the "dominant" relation, a signal appears on the appropriate output. The signal is the result of a "silence" on the appropriate line coming out of the "frequency fractionator." Silences in timing device designs, like engineers' "nulls" and the mathematical "0," are guides and standards of reference. E.g., when the "following" system above is "moving straight ahead directly toward the source of sensation," there are operational silences at pivotal points that are lost when the balance is tilted.
At page 41 of This Is Your Brain on Music, Levitin writes that "networks of neurons must form representations of musical structures and musical rules." In my systems, no "representations" are needed but "musical structures" can be directly embodied in proposed devices and networks of such devices. A central feature of the Quad Nets Model is "cycles within cycles" that can control musical "arches within arches" and account for a "theme and variations."
A more direct example explores "musical meter," which is the combination of an approximately steady "beat" with a regular emphasis, as in the common "4/4 meter," e.g., ONE-two-THREE-four. Levitin writes (page 68):
"We know that there are neural circuits specifically related to detecting and tracking musical meter, and we know that the cerebellum is involved in setting an internal clock or timer that can synchronize with events that are out-there-in-the-world."
Again, at p.174:
"The cerebellum is the part of the brain that is involved closely with timing and coordinated movements of the body. ... The function of this oldest part of the brain is something that is crucial to music: timing."
However, according to Levitin (p. 172):
"The only way we can feel or know these timing variations is if a computational system in the brain is extracting information about when the beats are supposed to occur."
The assembly of Quad Net device parts at the bottom of the image resembles the 4-cycle. The 4 white round objects are "Toroidal Quad Nets" (TQN's) that are collective forms of a simple timing device. The blue arrow-like objects are collective forms of simple projections. During operations, each TQN periodically generates a pulse bundle (a collective form of a single pulse) and pulse bundles circulate in the assembly of Quad Net devices at the same tempo as the circulating pulse in the 4-cycle. The 4-cycle drives the assembly of Quad Net device parts through (1) the "intermediary timing devices" that enable further fine-tuning of timing variations, (2) the "one-many connections" that use the equal-ouput rule and (3) green and purple "controllers." (This assembly of Quad Net device parts is a straightforward adaptation of the Phase Transfer Controller fully described in Quad Nets, § 2.i.)
An example of output from the 4/4 Musical Meter Generator is shown below. The "high-frequency" pulse bundles with more numerous pulses produce a more intense output than the "low-frequency" pulse bundles with less numerous pulses; more intense output means stronger muscular action or louder sound. A bit of timing variation is shown (in contrast to the "metronome" beat below the line) to illustrate the capacities of the assembly and in keeping with Levitin's observations that such variations are common in music produced by human musicians, in contrast to music produced by machines. Because the Quad Nets model is applicable to all brain parts, including those involved in emotions, timing of output signals can be varied according to a performer's emotions. Emotions are foreign to "computational models" such as that espoused by Levitin.
Materials on this page were originally published in 2007 near the beginning of a line of development that, as of 2011, has led to the most recent timing device designs. Major stages of development are listed below. Full details are in the ( ... ) Quad Net Site Map.
( ... ), web pages and materials, "Shimmering Silences in Beautiful Music / An inquiry into the nature of personal experience" (April 2009).
( ... ) a .pdf file "An Ear for Pythagorean Harmonics: Mathematical Processing in Brain Models Built From 'Timing Devices' " (2009) that was published as part of the web page.
( ... ) "An Ear for Pythagorean Harmonics" (December 2009).
( ... ) "An Ear for Pythagorean Harmonics: Brain Models Built From Timing Devices" (2009), - a .pdf file. The article includes an advanced design for an "engineered organism" that was developed from the design shown above and a model of brain activity of a musician who is "following the beat."
Brain Models Built From Timing Devices (2011)
( ... ) Opening Page
( ... ) A Kit of Parts
( ... ) An Eye for Sharp Contrast
( ... ) Eyes That Look at Objects
( ... ) An Ear for Pythagorean Harmonics
( ... ) A Procrustean Group of Harmonies
( ... ) Fundamentals of Timing Devices
( ... ) top of this page
( ... ) top of page.
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Copyright © 2007 Robert Kovsky, revised 2009, 2010, 2011