Brains as Computers- Computers as Brains?

The metaphor, analogy, theory, or reality of brains as computers?

A computer is a programmable device, whether it be electrical, analogue, or quantum. Due to his dualist belief that the mind programmes the brain, Wilder Penfield said that the brain functions just like a computer. If this kind of dualism is disregarded, specifying what a brain "programme" might entail and who is authorised to "programme" the brain will be necessary in order to identify the brain to a computer. This is a metaphor if the brain "programmes" itself while it learns. This is a metaphor if evolution "programmes" the brain.

In fact, the brain-computer metaphor is frequently used in the literature on neuroscience rather than as an analogy, or explicit comparison, by importing computer-related terms into discussions of the brain. For example, we claim that brains compute the locations of sounds, and we speculate about how perceptual algorithms are implemented in the brain.

WHAT IS A COMPUTER?

It is often claimed that the brain functions somewhat like a computer. Everyone knows that no one thinks that folks have USB ports and hard drives. A computer is, in a broader sense, a machine that can be programmed. An explicit collection of instructions called a programme ("pro-," before; "-gramme," write") fully specifies the behaviour of the system in advance. Programming for computers can be done in a variety of ways, including logic programming (using logical propositions, like in the language Prologue), procedural programming (using a set of basic procedures, such as in a recipe or the C language), and more. Computers that run programmes differently include "non-conventional" computers, parallel computers, analogue computers, quantum computers, and more.

AN ENTITY WITH DUALITY

Bell (1999) noted that the computer is fundamentally a dualistic entity, in which some hardware ("hardware") executes software ("software") that has been programmed by an outside actor. The brain is essentially a computer, according to Wilder Penfield, who discovered the cortical homunculi (sensory and motor "maps" of the body on the cortex) in 1975. Penfield believed that the brain functions like a computer that the mind programmes. He was a dualist.

Although Cartesian dualism has had a significant influence on modern neuroscience, most neuroscientists do not subscribe to it. Therefore, it is commonly accepted that the brain does not actually get programming from an outside source. It's possible that the brain's computer is "programmed by evolution" or "self-programmed," although these metaphors are somewhat nebulous. In order to give some meaning to the claim that "the brain is a computer," it is necessary to pinpoint the brain's programmes and a mechanism for arbitrary alteration.

For instance, according to classical connectionism, the programme is the collection of synaptic weights, and these weights may vary as a result of many processes. This viewpoint, like any attempt to locate a programme in the brain, presupposes that the brain can be divided into a set of changeable components (software) and a fixed set of processes (hardware) that act on those components. If this assumption were false, the "programme" in question would not be able to clearly state what it does, and thus would not be a programme at all. However, synaptic weights are by far means the only aspects of the brain that may be changed. 

Bell (1999) argued against this hardware/software distinction because everything in the brain or a biological organism is "soft": "A computer is an intrinsically dualistic entity, with its physical set-up designed to not interfere with its logical set-up, which executes the computation.

THEORY, ANALOGY OR METAPHOR?

Therefore, the claim that brains are computers is untrue. It might be a specific kind of connectionist or dualist theory, but those theories are incompatible with what we understand about the biology of the brain. However, the statement is typically not accepted literally in the literature on neuroscience. Is it a metaphor or an analogy? An analogy is explicit, whereas a metaphor is implicit, and this is the difference. Although it may occasionally be said that the brain functions similarly to a computer, the terms sensory computation, decision-making algorithms, hardware, software, reading and writing the brain (for stimulating and measuring), biological implementation, neural codes, and other terms are much more frequently used in the neuroscience literature. 

These are blatant examples of metaphorical writing that borrows from the computer lexicon without directly equating the brain with a computer.

By limiting what we see, emphasising what we do see, and providing some of the inferential frameworks we use to reason, metaphor helps us focus.

ALGORITHMS OF THE BRAIN

When we claim that the brain uses algorithms, what exactly do we mean? According to Cormen et al. (2009), an algorithm is defined as "a sequence of computational steps that transform the input into the output" in computer science textbooks. There are various ways to define those stages, but they must be part of a process that can be reduced to a small number of simple activities carried out in a specific sequence.

The solar system is one example of something that is not algorithmic. Planetary motion is subject to some laws, but it is not reducible to a finite set of operations. These principles serve as a model, not an algorithm, of how planets move. 

The majority of biophysical models of the brain are dynamical systems. However, dynamical systems are not always algorithms, therefore claiming that the brain uses algorithms is a specific claim that requires proof. One must name basic brain functions in order to defend them. For instance, the computational theory of mind maintains that manipulation of symbols constitutes cognition, meaning that basic processes are symbolic operations.

This remains the problem of how the brain recognises symbols, which is typically accomplished using the idea of "neural codes," although this idea is flawed both conceptually and empirically. Examples include Marr (1982) who unsuccessfully attempted to characterise vision as a series of well-defined signal processing processes and Minsky (1988) who attempted to characterise cognition in terms of fundamental cognitive activities. In general, it is not so clear that algorithms can fully capture behaviour.

Sometimes the term "algorithm" is used in a more general meaning to refer to a precise quantitative explanation of how the brain works. However, this metaphorical application is unclear because not all of what is legal in the world is algorithmic. There are many different types of models, and a quantitative description is a model, not an algorithm.

CONCLUSION

Computers can be programmed. In a literal sense, brains are not.

The analogy between the brain and a computer is true, with the exception of certain uncommon Cartesian viewpoints in which the mind is thought to program the brain. Although explicit formal comparisons with computers are uncommon, brain functions are frequently described using terms from the computer lexicon (such as algorithms, computing, hardware, and software). Because computers are figuratively defined using mental terminology (e.g., they memorize information), it is actually a double metaphor. The reason the metaphor is (deceitfully) appealing can be attributed to this circular metaphorical link.

The "genetic programme" is a source of confusion in genetics, just as the "brain-computer" metaphor is in the literature on neuroscience. The term "computer" can refer to both something complex and beneficial. However, since computers run programmes, whatever programmes are we talking about? Evolution? a connectome? Both are misrepresented as programmes even if neither is one in reality. In a metaphor, the term "algorithm" can also refer to "laws" or "models." However, this is misleading because the term "algorithm" implies simple operations and codes, which are not present in all models and most definitely are not evident in brains.

It's unclear exactly what is meant when the word "computation" is used metaphorically. Is it being said that cognition is algorithmic? about representations? or just about having appropriate behaviour?

The scientific discussion might start if the correct definitions of these computer terminology are made public.