A positronic brain is a fictional technological device, originally conceived by

science fiction Science fiction (often shortened to sci-fi or abbreviated SF) is a genre of speculative fiction that deals with imaginative and futuristic concepts. These concepts may include information technology and robotics, biological manipulations, space ...

writer

Isaac Asimov Isaac Asimov ( ; – April 6, 1992) was an Russian-born American writer and professor of biochemistry at Boston University. During his lifetime, Asimov was considered one of the "Big Three" science fiction writers, along with Robert A. H ...

. It functions as a

central processing unit A central processing unit (CPU), also called a central processor, main processor, or just processor, is the primary Processor (computing), processor in a given computer. Its electronic circuitry executes Instruction (computing), instructions ...

(CPU) for

robot A robot is a machine—especially one Computer program, programmable by a computer—capable of carrying out a complex series of actions Automation, automatically. A robot can be guided by an external control device, or the robot control, co ...

s, and, in some unspecified way, provides them with a form of

consciousness Consciousness, at its simplest, is awareness of a state or object, either internal to oneself or in one's external environment. However, its nature has led to millennia of analyses, explanations, and debate among philosophers, scientists, an ...

recognizable to

human Humans (''Homo sapiens'') or modern humans are the most common and widespread species of primate, and the last surviving species of the genus ''Homo''. They are Hominidae, great apes characterized by their Prehistory of nakedness and clothing ...

s. When Asimov wrote his first robot stories in 1939 and 1940, the

positron The positron or antielectron is the particle with an electric charge of +1''elementary charge, e'', a Spin (physics), spin of 1/2 (the same as the electron), and the same Electron rest mass, mass as an electron. It is the antiparticle (antimatt ...

was a newly discovered particle, and so the

buzz word A buzzword is a word or phrase, new or already existing, that becomes popular for a period of time. Buzzwords often derive from technical terms yet often have much of the original technical meaning removed through fashionable use, being simply ...

"positronic" added a scientific connotation to the concept. Asimov's 1942 short story " Runaround" elaborates his fictional Three Laws of Robotics, which are ingrained in the positronic brains of nearly all of his robots.

Conceptual overview

Asimov remained vague about the technical details of positronic brains except to assert that their substructure was formed from an alloy of

platinum Platinum is a chemical element; it has Symbol (chemistry), symbol Pt and atomic number 78. It is a density, dense, malleable, ductility, ductile, highly unreactive, precious metal, precious, silverish-white transition metal. Its name origina ...

and iridium. They were said to be vulnerable to radiation and apparently involve a type of

volatile memory Volatile memory, in contrast to non-volatile memory, is computer memory that requires power to maintain the stored information; it retains its contents while powered on but when the power is interrupted, the stored data is quickly lost. Volatile ...

(since robots in storage required a power source keeping their brains "alive"). The focus of Asimov's stories was directed more toward the

software Software consists of computer programs that instruct the Execution (computing), execution of a computer. Software also includes design documents and specifications. The history of software is closely tied to the development of digital comput ...

of robots—such as the Three Laws of Robotics—than the hardware in which it was implemented, although it is stated in his stories that to create a positronic brain without the Three Laws, it would have been necessary to spend years redesigning the fundamental approach toward the brain itself. Within his stories of

robotics Robotics is the interdisciplinary study and practice of the design, construction, operation, and use of robots. Within mechanical engineering, robotics is the design and construction of the physical structures of robots, while in computer s ...

Earth Earth is the third planet from the Sun and the only astronomical object known to Planetary habitability, harbor life. This is enabled by Earth being an ocean world, the only one in the Solar System sustaining liquid surface water. Almost all ...

and their development by U.S. Robots, Asimov's positronic brain is less of a plot device and more of a technological item worthy of study. A positronic brain cannot ordinarily be built without incorporating the Three Laws; any modification thereof would drastically modify robot behavior. Behavioral dilemmas resulting from conflicting potentials set by inexperienced and/or malicious users of the robot for the Three Laws make up the bulk of Asimov's stories concerning robots. They are resolved by applying the

science Science is a systematic discipline that builds and organises knowledge in the form of testable hypotheses and predictions about the universe. Modern science is typically divided into twoor threemajor branches: the natural sciences, which stu ...

of logic and

psychology Psychology is the scientific study of mind and behavior. Its subject matter includes the behavior of humans and nonhumans, both consciousness, conscious and Unconscious mind, unconscious phenomena, and mental processes such as thoughts, feel ...

together with

mathematics Mathematics is a field of study that discovers and organizes methods, Mathematical theory, theories and theorems that are developed and Mathematical proof, proved for the needs of empirical sciences and mathematics itself. There are many ar ...

, the supreme solution finder being Dr. Susan Calvin, Chief Robopsychologist of U.S. Robots. The Three Laws are also a bottleneck in brain sophistication. Very complex brains designed to handle world economy interpret the First Law in an expanded sense to include humanity as opposed to a single human; in Asimov's later works like '' Robots and Empire'' this is referred to as the " Zeroth Law". At least one brain constructed as a calculating

machine A machine is a physical system that uses power to apply forces and control movement to perform an action. The term is commonly applied to artificial devices, such as those employing engines or motors, but also to natural biological macromol ...

, as opposed to being a robot control circuit, was designed to have a flexible, childlike personality so that it was able to pursue difficult problems without the Three Laws inhibiting it completely. Specialized brains created for overseeing world economics were stated to have no personality at all. Under specific conditions, the Three Laws can be obviated, with the modification of the actual robotic design. * Robots that are of low enough value can have the Third Law deleted; they do not have to protect themselves from harm, and the brain size can be reduced by half. * Robots that do not require orders from a human being may have the Second Law deleted, and therefore require smaller brains again, providing they do not require the Third Law. * Robots that are disposable, cannot receive orders from a human being and are not able to harm a human, will not require even the First Law. The sophistication of positronic circuitry renders a brain so small that it could comfortably fit within the skull of an insect. Robots of the last type directly parallel contemporary industrial robotics practice, though real-life robots do contain safety sensors and systems (a weak form of the First Law; the robot is a safe tool to use, but has no "judgment", which is implicit in Asimov's own stories).

References

{{Robot series Fictional computers Foundation universe Fictional elements introduced in 1939

Conceptual overview

Further reading

References