What is symbolic artificial intelligence?

Our system, called Neuro-Symbolic QA (NSQA),2 translates a given natural language question into a logical form and then uses our neuro-symbolic reasoner LNN to reason over a knowledge base to produce the answer. In response to these limitations, there has been a shift towards data-driven approaches like neural networks and deep learning. However, there is a growing interest in neuro-symbolic AI, which aims to combine the strengths of symbolic AI and neural networks to create systems that can both reason with symbols and learn from data. In natural language processing, symbolic AI has been employed to develop systems capable of understanding, parsing, and generating human language. Through symbolic representations of grammar, syntax, and semantic rules, AI models can interpret and produce meaningful language constructs, laying the groundwork for language translation, sentiment analysis, and chatbot interfaces.

It is also being explored in combination with other AI techniques to address more challenging reasoning tasks and to create more sophisticated AI systems. The recent adaptation of deep neural network-based methods to reinforcement learning and planning domains has yielded remarkable progress on individual tasks. In pursuit of efficient and robust generalization, we introduce the Schema Network, an object-oriented generative physics simulator capable of disentangling multiple causes of events and reasoning backward through causes to achieve goals. The richly structured architecture of the Schema Network can learn the dynamics of an environment directly from data. We argue that generalizing from limited data and learning causal relationships are essential abilities on the path toward generally intelligent systems.

There have been several efforts to create complicated symbolic AI systems that encompass the multitudes of rules of certain domains. Called expert systems, these symbolic AI models use hardcoded knowledge and rules to tackle complicated tasks such as medical diagnosis. But they require a huge amount of effort by domain experts and software engineers and only work in very narrow use cases. As soon as you generalize the problem, there will be an explosion of new rules to add (remember the cat detection problem?), which will require more human labor. Symbolic artificial intelligence, also known as symbolic AI or classical AI, refers to a type of AI that represents knowledge as symbols and uses rules to manipulate these symbols.

Neuro-Symbolic Question Answering

Below is a quick overview of approaches to knowledge representation and automated reasoning. The key AI programming language in the US during the last symbolic AI boom period was LISP. LISP is the second oldest programming language after FORTRAN and was created in 1958 by John McCarthy. LISP provided the first read-eval-print loop to support rapid program development.

Neural Networks excel in learning from data, handling ambiguity, and flexibility, while Symbolic AI offers greater explainability and functions effectively with less data. Logic Programming, a vital concept in Symbolic AI, integrates Logic Systems and AI algorithms. It represents problems using relations, rules, and facts, providing a foundation for AI reasoning and decision-making, a core aspect of Cognitive Computing.

These systems are essentially piles of nested if-then statements drawing conclusions about entities (human-readable concepts) and their relations (expressed in well understood semantics like X is-a man or X lives-in Acapulco). We believe that our results are the first step to direct learning representations in the neural networks towards symbol-like entities that can be manipulated by high-dimensional computing. Such an approach facilitates fast and lifelong learning and paves the way for high-level reasoning and manipulation of objects. Despite the difference, they have both evolved to become standard approaches to AI and there is are fervent efforts by research community to combine the robustness of neural networks with the expressivity of symbolic knowledge representation. A paper on Neural-symbolic integration talks about how intelligent systems based on symbolic knowledge processing and on artificial neural networks, differ substantially.

Since its foundation as an academic discipline in 1955, Artificial Intelligence (AI) research field has been divided into different camps, of which symbolic AI and machine learning. While symbolic AI used to dominate in the first decades, machine learning has been very trendy lately, so let’s try to understand each of these approaches and their main differences when applied to Natural Language Processing (NLP). Good-Old-Fashioned Artificial Intelligence (GOFAI) is more like a euphemism for Symbolic AI is characterized by an exclusive focus on symbolic reasoning and logic. However, the approach soon lost fizzle since the researchers leveraging the GOFAI approach were tackling the “Strong AI” problem, the problem of constructing autonomous intelligent software as intelligent as a human. If one looks at the history of AI, the research field is divided into two camps – Symbolic & Non-symbolic AI that followed different path towards building an intelligent system. Symbolists firmly believed in developing an intelligent system based on rules and knowledge and whose actions were interpretable while the non-symbolic approach strived to build a computational system inspired by the human brain.

Our chemist was Carl Djerassi, inventor of the chemical behind the birth control pill, and also one of the world’s most respected mass spectrometrists. We began to add to their knowledge, inventing knowledge of engineering as we went along. We hope that by now you’re convinced that symbolic AI is a must when it comes to NLP applied to chatbots. Machine learning can be applied to lots of disciplines, and one of those is Natural Language Processing, which is used in AI-powered conversational chatbots.

Non-symbolic AI systems do not manipulate a symbolic representation to find solutions to problems. Instead, they perform calculations according to some principles that have demonstrated to be able to solve problems. Examples of Non-symbolic AI include genetic algorithms, neural networks and deep learning. The origins of non-symbolic AI come from the attempt to mimic a human brain and its complex network of interconnected neurons. In conclusion, Symbolic AI and connectionist AI are two paradigms of AI where the first has its methods and capabilities, while the second has its place and purpose as well. Symbolic AI uses rules and logical structures to solve problems based on the principle of warrantable knowledge while non-symbolic AI directly analyzes data from a problem based on available data.

Our researchers are working to usher in a new era of AI where machines can learn more like the way humans do, by connecting words with images and mastering abstract concepts. As AI continues to evolve, the integration of both paradigms, often referred to as neuro-symbolic AI, aims to harness the strengths of each to build more robust, efficient, and intelligent systems. This approach promises to expand AI’s potential, combining the clear reasoning of symbolic AI with the adaptive learning capabilities of subsymbolic AI. Symbolic AI, a subfield of AI focused on symbol manipulation, has its limitations. Its primary challenge is handling complex real-world scenarios due to the finite number of symbols and their interrelations it can process.

Symbolic AI’s logic-based approach contrasts with Neural Networks, which are pivotal in Deep Learning and Machine Learning. Neural Networks learn from data patterns, evolving through AI Research and applications. When deep learning reemerged in 2012, it was with a kind of take-no-prisoners attitude that has characterized most of the last decade.

Background / history of symbolic ai

The words sign and symbol derive from Latin and Greek words, respectively, that mean mark or token, as in “take this rose as a token of my esteem.” Both words mean “to stand for something else” or “to represent something else”. Opposing Chomsky’s views that a human is born with Universal Grammar, a kind of knowledge, John Locke[1632–1704] postulated that mind is a blank slate or tabula rasa. Symbolic AI’s growing role in healthcare reflects the integration of AI Research findings into practical AI Applications. Expert Systems, a significant application of Symbolic AI, demonstrate its effectiveness in healthcare, a field where AI Applications are increasingly prominent.

Program tracing, stepping, and breakpoints were also provided, along with the ability to change values or functions and continue from breakpoints or errors. It had the first self-hosting compiler, meaning that the compiler itself was originally written in LISP and then ran interpretively to compile the compiler code. Expert systems can operate in either a forward chaining – from evidence to conclusions – or backward chaining – from goals to needed data and prerequisites – manner. More advanced knowledge-based systems, such as Soar can also perform meta-level reasoning, that is reasoning about their own reasoning in terms of deciding how to solve problems and monitoring the success of problem-solving strategies.

Neural networks are almost as old as symbolic AI, but they were largely dismissed because they were inefficient and required compute resources that weren’t available at the time. In the past decade, thanks to the large availability of data and processing power, deep learning has gained popularity and has pushed past symbolic AI systems. Question-answering is the first major use case for the LNN technology we’ve developed. While achieving state-of-the-art performance on the two KBQA datasets is an advance over other AI approaches, these datasets do not display the full range of complexities that our neuro-symbolic approach can address.

We present the details of the model, the algorithm powering its automatic learning ability, and describe its usefulness in different use cases. The purpose of this paper is to generate broad interest to develop it within an open source project centered on the Deep Symbolic Network (DSN) model towards the development of general AI. Each approach—symbolic, connectionist, and behavior-based—has advantages, but has been criticized by the other approaches. Symbolic what is symbolic ai AI has been criticized as disembodied, liable to the qualification problem, and poor in handling the perceptual problems where deep learning excels. In turn, connectionist AI has been criticized as poorly suited for deliberative step-by-step problem solving, incorporating knowledge, and handling planning. Finally, Nouvelle AI excels in reactive and real-world robotics domains but has been criticized for difficulties in incorporating learning and knowledge.

While, as compared to Subsymbolic AI, symbolic AI is more informative and general, however, it is more complicated in terms of rule set and knowledge base and is scalable to a certain degree at a time. Instead, Connectionist AI is more scalable, it relies on processing power and large sets of data to build capable agents that can handle more complicated tasks and huge projects. Connectionist AI, also known as neural networks or sub-symbolic AI, represents knowledge through connections and weights within a network of artificial neurons.

As a consequence, the Botmaster’s job is completely different when using Symbolic AI technology than with Machine Learning-based technology as he focuses on writing new content for the knowledge base rather than utterances of existing content. He also has full transparency on how to fine-tune the engine when it doesn’t work properly as he’s been able to understand why a specific decision has been made and has the tools to fix it. These soft reads and writes form a bottleneck when implemented in the conventional von Neumann architectures (e.g., CPUs and GPUs), especially for AI models demanding over millions of memory entries. Thanks to the high-dimensional geometry of our resulting vectors, their real-valued components can be approximated by binary, or bipolar components, taking up less storage. More importantly, this opens the door for efficient realization using analog in-memory computing.

In these fields, Symbolic AI has had limited success and by and large has left the field to neural network architectures (discussed in a later chapter) which are more suitable for such tasks. In sections to follow we will elaborate on important sub-areas of Symbolic AI as well as difficulties encountered by this approach. So to summarize, one of the main differences between machine learning and traditional symbolic reasoning is how the learning happens. In machine learning, the algorithm learns rules as it establishes correlations between inputs and outputs.

In conclusion, Symbolic AI is a captivating approach to artificial intelligence that uses symbols and logical rules for knowledge representation and reasoning. Combining Symbolic AI with other AI techniques can lead to powerful and versatile AI systems for various applications. (…) Machine learning algorithms build a mathematical model based on sample data, known as ‘training data’, in order to make predictions or decisions without being explicitly programmed to perform the task”. One such project is the Neuro-Symbolic Concept Learner (NSCL), a hybrid AI system developed by the MIT-IBM Watson AI Lab.

These rules can be used to make inferences, solve problems, and understand complex concepts. This approach is highly interpretable as the reasoning process can be traced back to the logical rules used. A certain set of structural rules are innate to humans, independent of sensory experience. With more linguistic stimuli received in the course of psychological development, children then adopt specific syntactic rules that conform to Universal grammar.

Improvements in Knowledge Representation will boost Symbolic AI’s modeling capabilities, a focus in AI History and AI Research Labs. Neural Networks’ dependency on extensive data sets differs from Symbolic AI’s effective function with limited data, a factor crucial in AI Research Labs and AI Applications. Rule-Based AI, a cornerstone of Symbolic AI, involves creating AI systems that apply predefined rules.

At the heart of Symbolic AI lie key concepts such as Logic Programming, Knowledge Representation, and Rule-Based AI. McCarthy’s approach to fix the frame problem was circumscription, a kind of non-monotonic logic where deductions could be made from actions that need only specify what would change while not having to explicitly specify everything that would not change. Other non-monotonic logics provided truth maintenance systems that revised beliefs leading to contradictions. A similar problem, called the Qualification Problem, occurs in trying to enumerate the preconditions for an action to succeed. An infinite number of pathological conditions can be imagined, e.g., a banana in a tailpipe could prevent a car from operating correctly.

Deep learning and neural networks excel at exactly the tasks that symbolic AI struggles with. They have created a revolution in computer vision applications such as facial recognition and cancer detection. The advantage of neural networks is that they can deal with messy and unstructured data. Instead of manually laboring through the rules of detecting cat pixels, you can train a deep learning algorithm on many pictures of cats. When you provide it with a new image, it will return the probability that it contains a cat.

Symbolic AI has been used in a wide range of applications, including expert systems, natural language processing, and game playing. It can be difficult to represent complex, ambiguous, or uncertain knowledge with symbolic AI. Furthermore, symbolic AI systems are typically hand-coded and do not learn from data, which can make them brittle and inflexible. The origins of symbolic AI can be traced back to the early days of AI research, particularly in the 1950s and 1960s, when pioneers such as John McCarthy and Allen Newell laid the foundations for this approach.

We chose to focus on KBQA because such tasks truly demand advanced reasoning such as multi-hop, quantitative, geographic, and temporal reasoning. Our NSQA achieves state-of-the-art accuracy on two prominent KBQA datasets without the need for end-to-end dataset-specific training. Due to the explicit formal use of reasoning, NSQA can also explain how the system arrived at an answer by precisely laying out the steps of reasoning.

At the height of the AI boom, companies such as Symbolics, LMI, and Texas Instruments were selling LISP machines specifically targeted to accelerate the development of AI applications and research. In addition, several artificial intelligence companies, such as Teknowledge and Inference Corporation, were selling expert system shells, training, and consulting to corporations. But for the moment, symbolic AI is the leading method to deal with problems that require logical thinking and knowledge representation.

In NLP, symbolic AI contributes to machine translation, question answering, and information retrieval by interpreting text. For knowledge representation, it underpins expert systems and decision support systems, organizing and accessing information efficiently. In planning, symbolic AI is crucial for robotics and automated systems, generating sequences of actions to meet objectives. Symbolic AI was the dominant paradigm from the mid-1950s until the mid-1990s, and it is characterized by the explicit embedding of human knowledge and behavior rules into computer programs.

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Hobbes was influenced by Galileo, just as Galileo thought that geometry could represent motion, Furthermore, as per Descartes, geometry can be expressed as algebra, which is the study of mathematical symbols and the rules for manipulating these symbols. René Descartes, a mathematician, and philosopher, regarded thoughts themselves as symbolic representations and Perception as an internal process. Despite its strengths, Symbolic AI faces challenges, such as the difficulty in encoding all-encompassing knowledge and rules, and the limitations in handling unstructured data, unlike AI models based on Neural Networks and Machine Learning. Symbolic AI’s application in financial fraud detection showcases its ability to process complex AI algorithms and logic systems, crucial in AI Research and AI Applications.

Our model builds an object-based scene representation and translates sentences into executable, symbolic programs. To bridge the learning of two modules, we use a neuro-symbolic reasoning module that executes these programs on the latent scene representation. Analog to the human concept learning, given the parsed program, the perception module learns visual concepts based on the language description of the object being referred to. Meanwhile, the learned visual concepts facilitate learning new words and parsing new sentences.

In this view, deep learning best models the first kind of thinking while symbolic reasoning best models the second kind and both are needed. Meanwhile, many of the recent breakthroughs have been in the realm of “Weak AI” — devising AI systems that can solve a specific problem perfectly. But of late, there has been a groundswell of activity around combining the Symbolic AI approach with Deep Learning in University labs. And, the theory is being revisited by Murray Shanahan, Professor of Cognitive Robotics Imperial College London and a Senior Research Scientist at DeepMind.

Connectionist, or neural network AI which is based on the structure of the human brain, processes data and adapts easily to new data as it relies on patterns. In combination, all of the approaches that are shared above work hand in hand in advancing artificial intelligence as well as intelligent systems and applications that are diverse. Symbolic AI, also known as «good old-fashioned AI» (GOFAI), relies on high-level human-readable symbols for processing and reasoning. You can foun additiona information about ai customer service and artificial intelligence and NLP. It involves explicitly encoding knowledge and rules about the world into computer understandable language.

Similar to the problems in handling dynamic domains, common-sense reasoning is also difficult to capture in formal reasoning. Examples of common-sense reasoning include implicit reasoning about how people think or general knowledge of day-to-day events, objects, and living creatures. During the first AI summer, many people thought that machine intelligence could be achieved in just a few years. By the mid-1960s neither useful natural language translation systems nor autonomous tanks had been created, and a dramatic backlash set in.

In contrast to the US, in Europe the key AI programming language during that same period was Prolog. Prolog provided a built-in store of facts and clauses that could be queried by a read-eval-print loop. The store could act as a knowledge base and the clauses could act as rules or a restricted form of logic.

Automated planning

If machine learning can appear as a revolutionary approach at first, its lack of transparency and a large amount of data that is required in order for the system to learn are its two main flaws. Companies now realize how important it is to have a transparent AI, not only for ethical reasons but also for operational ones, and the deterministic (or symbolic) approach is now becoming popular again. In a nutshell, symbolic AI involves the explicit embedding of human knowledge and behavior rules into computer programs. As you can easily imagine, this is a very heavy and time-consuming job as there are many many ways of asking or formulating the same question.

Samuel’s Checker Program[1952] — Arthur Samuel’s goal was to explore to make a computer learn. The program improved as it played more and more games and ultimately defeated its own creator. This lead towards the connectionist paradigm of AI, also called non-symbolic AI which gave rise to learning and neural network-based approaches to solve AI. Henry Kautz,[19] Francesca Rossi,[81] and Bart Selman[82] have also argued for a synthesis.

Despite the emergence of alternative paradigms such as connectionism and statistical learning, symbolic AI continues to inspire a deep understanding of symbolic representation and reasoning, enriching the broader landscape of AI research and applications. Deep reinforcement learning (DRL) brings the power of deep neural networks to bear on the generic task of trial-and-error learning, and its effectiveness has been convincingly demonstrated on tasks such as Atari video games and the game of Go. However, contemporary DRL systems inherit a number of shortcomings from the current generation of deep learning techniques. For example, they require very large datasets to work effectively, entailing that they are slow to learn even when such datasets are available.

In particular, the level of reasoning required by these questions is relatively simple. They also assume complete world knowledge and do not perform as well on initial experiments testing learning and reasoning. A second flaw in symbolic reasoning is that the computer itself doesn’t know what the symbols mean; i.e. they are not necessarily linked to any other representations of the world in a non-symbolic way. Again, this stands in contrast to neural nets, which can link symbols to vectorized representations of the data, which are in turn just translations of raw sensory data. So the main challenge, when we think about GOFAI and neural nets, is how to ground symbols, or relate them to other forms of meaning that would allow computers to map the changing raw sensations of the world to symbols and then reason about them.

Symbolic AI, a branch of artificial intelligence, focuses on the manipulation of symbols to emulate human-like reasoning for tasks such as planning, natural language processing, and knowledge representation. Unlike other AI methods, symbolic AI excels in understanding and manipulating symbols, which is essential for tasks that require complex reasoning. However, these algorithms tend to operate more slowly due to the intricate nature of human thought processes they aim to replicate. Despite this, symbolic AI is often integrated with other AI techniques, including neural networks and evolutionary algorithms, to enhance its capabilities and efficiency. The significance of symbolic AI lies in its role as the traditional framework for modeling intelligent systems and human cognition. It underpins the understanding of formal logic, reasoning, and the symbolic manipulation of knowledge, which are fundamental to various fields within AI, including natural language processing, expert systems, and automated reasoning.

Additionally, ensuring the adaptability of symbolic AI in dynamic, uncertain environments poses a significant implementation hurdle. Artificial Intelligence (AI) is a vast field with various approaches to creating intelligent systems. Understanding the differences, advantages, and limitations of each can help determine the best approach for a given application and explore the potential of combining both approaches. Thus contrary to pre-existing cartesian philosophy he maintained that we are born without innate ideas and knowledge is instead determined only by experience derived by a sensed perception. Children can be symbol manipulation and do addition/subtraction, but they don’t really understand what they are doing.

Its ability to process complex rules and logic makes it ideal for fields requiring precision and explainability, such as legal and financial domains. The automated theorem provers discussed below can prove theorems in first-order logic. Horn clause logic is more restricted than first-order logic and is used in logic programming languages such as Prolog.

• Each method executes a series of rule-based instructions that might read and change the properties of the current and other objects.
• Symbolic AI, a branch of artificial intelligence, focuses on the manipulation of symbols to emulate human-like reasoning for tasks such as planning, natural language processing, and knowledge representation.
• They can simplify sets of spatiotemporal constraints, such as those for RCC or Temporal Algebra, along with solving other kinds of puzzle problems, such as Wordle, Sudoku, cryptarithmetic problems, and so on.
• This interpretability is particularly advantageous for tasks requiring human-like reasoning, such as planning and decision-making, where understanding the AI’s thought process is crucial.
• The program improved as it played more and more games and ultimately defeated its own creator.

This fusion holds promise for creating hybrid AI systems capable of robust knowledge representation and adaptive learning. Symbolic AI has been instrumental in the creation of expert systems designed to emulate human expertise and decision-making in specialized domains. By encoding domain-specific knowledge as symbolic rules and logical inferences, expert systems have been deployed in fields such as medicine, finance, and engineering to provide intelligent recommendations and problem-solving capabilities. Implementations of symbolic reasoning are called rules engines or expert systems or knowledge graphs. Google made a big one, too, which is what provides the information in the top box under your query when you search for something easy like the capital of Germany.

In the paper, we show that a deep convolutional neural network used for image classification can learn from its own mistakes to operate with the high-dimensional computing paradigm, using vector-symbolic architectures. It does so by gradually learning to assign dissimilar, such as quasi-orthogonal, vectors to different image classes, mapping them far away from each other in the high-dimensional space. One promising approach towards this more general AI is in combining neural networks with symbolic AI. In our paper “Robust High-dimensional Memory-augmented Neural Networks” published in Nature Communications,1 we present a new idea linked to neuro-symbolic AI, based on vector-symbolic architectures. Deep neural networks are also very suitable for reinforcement learning, AI models that develop their behavior through numerous trial and error. This is the kind of AI that masters complicated games such as Go, StarCraft, and Dota.

Its history was also influenced by Carl Hewitt’s PLANNER, an assertional database with pattern-directed invocation of methods. This approach was experimentally verified for a few-shot image classification task involving a dataset of 100 classes of images with just five training examples per class. Although operating with 256,000 noisy nanoscale phase-change memristive devices, there was just a 2.7 percent accuracy drop compared to the conventional software realizations in high precision. Many of the concepts and tools you find in computer science are the results of these efforts.

2) The two problems may overlap, and solving one could lead to solving the other, since a concept that helps explain a model will also help it recognize certain patterns in data using fewer examples. The grandfather of AI, Thomas Hobbes said — Thinking is manipulation of symbols and Reasoning is computation. Symbolic AI offers clear advantages, including its ability to handle complex logic systems and provide explainable AI decisions. Symbolic AI’s role in industrial automation highlights its practical application in AI Research and AI Applications, where precise rule-based processes are essential. Symbolic AI-driven chatbots exemplify the application of AI algorithms in customer service, showcasing the integration of AI Research findings into real-world AI Applications. In legal advisory, Symbolic AI applies its rule-based approach, reflecting the importance of Knowledge Representation and Rule-Based AI in practical applications.

Ongoing research and development milestones in AI, particularly in integrating Symbolic AI with other AI algorithms like neural networks, continue to expand its capabilities and applications. Natural language processing focuses on treating language as data to perform tasks such as identifying topics without necessarily understanding the intended meaning. Natural language understanding, in contrast, constructs a meaning representation and uses that for further processing, such as answering questions. Semantic networks, conceptual graphs, frames, and logic are all approaches to modeling knowledge such as domain knowledge, problem-solving knowledge, and the semantic meaning of language. DOLCE is an example of an upper ontology that can be used for any domain while WordNet is a lexical resource that can also be viewed as an ontology. YAGO incorporates WordNet as part of its ontology, to align facts extracted from Wikipedia with WordNet synsets.

NSCL uses both rule-based programs and neural networks to solve visual question-answering problems. As opposed to pure neural network–based models, the hybrid AI can learn new tasks with less data and is explainable. And unlike symbolic-only models, NSCL doesn’t struggle to analyze the content of images.

Meanwhile, a paper authored by Sebastian Bader and Pascal Hitzler talks about an integrated neural-symbolic system, powered by a vision to arrive at a more powerful reasoning and learning systems for computer science applications. This line of research indicates that the theory of integrated neural-symbolic Chat GPT systems has reached a mature stage but has not been tested on real application data. Symbolic AI is still relevant and beneficial for environments with explicit rules and for tasks that require human-like reasoning, such as planning, natural language processing, and knowledge representation.

Symbols can represent abstract concepts (bank transaction) or things that don’t physically exist (web page, blog post, etc.). Symbols can be organized into hierarchies (a car is made of doors, windows, https://chat.openai.com/ tires, seats, etc.). They can also be used to describe other symbols (a cat with fluffy ears, a red carpet, etc.). If I tell you that I saw a cat up in a tree, your mind will quickly conjure an image.

This concept is fundamental in AI Research Labs and universities, contributing to significant Development Milestones in AI. Japan championed Prolog for its Fifth Generation Project, intending to build special hardware for high performance. Similarly, LISP machines were built to run LISP, but as the second AI boom turned to bust these companies could not compete with new workstations that could now run LISP or Prolog natively at comparable speeds.

Neural Networks, compared to Symbolic AI, excel in handling ambiguous data, a key area in AI Research and applications involving complex datasets. Forward chaining inference engines are the most common, and are seen in CLIPS and OPS5. Backward chaining occurs in Prolog, where a more limited logical representation is used, Horn Clauses. During training and inference using such an AI system, the neural network accesses the explicit memory using expensive soft read and write operations. We use symbols all the time to define things (cat, car, airplane, etc.) and people (teacher, police, salesperson).