Week 6

• alan turing invented the idea of the universal turing machine
• the universal turing machine can do any computation given a set of input data and an algorithm defined as a finite state machine
• thinking = representations of mental data + mental process
• implementing mental processes on computers allows researchers to:

  • validate their hypothesis by comparing computer results with human responses
  • generate models that can be used to develop intelligent application and robots
• rationality implies that there was some sort of reason behind a behaviour or thought that may not have a firm truth value
• logic is firm and conclusions are made based on premises that have definite truth value
• logic is used in problem solving and decision making
• deductive reasoning uses facts and implications
• inductive reasoning creates new knowledge from generalizing evidences
• abductive reasoning is logical inference that is drawn backwards using logic implications
• propositional logic: simpler, but hides the pattern from similar sentence structure as each sentence is encoded using a different code
• predicate logic: separates predicate from variables (better to learn patterns)
• syllogism (inference) is a kind of logical argument that applies deductive reasoning to arrive at a conclusion based on two or more propositions that are asserted or assumed to be true
• implications mean: if antecedent is true, it implies that the consequent will definitely be true
• logic implications can be used with deductive reasoning (forward) to check if antecedent is true, then the consequent must be true to answer questions or make decisions
• we can use logic propositions and rules to validate the "truth value" of the hypothesis
• prolog stands for programming logic

  • a computer programming language using which we can tell a computer to answer questions based on predefined facts and logic propositions
• rules are mental representations of the form if(condition), then (action)
• forward chaining with rules are used in production systems - similar to turing's FSM

  • rules are searched for something that matches a given state
  • one rule is selected and executed that modifies the state according to the rule
  • this moves the system step by step towards the goal state
• backward chaining in rules work backwords from goal to start: allows one to track possible causes for an action by inspecting the current state
• what are some of the ways that cognitive scientists explore the steps of the processes of rules?

  problem solving, planning, decision making
• we learn new rules by:

  • trial and error when doing some task and experiencing cause and effect
  • from external knowledge sources
  • breaking down other rules using chunking
• what are the limitations of rules?

  inflexible, difficult to control or process and follow
• tacit knowledge is difficult to transfer
• rules are generally static and require manual update every time rules change
• expert systems such as solving a computer problem are based on rules, but it is often very difficult to extract the rules from the experts
• language learning and use requires rules (and NLP)
• there are phonetic rules for pronunciation
• there are syntactic rules like forming questions
• chomsky thinks that every human is born with an innate sense of universal grammar (innateness)
• what are the prioritizing facts that apply when selecting a rule?

  specificity, operational, recency, dependency
• specificity: more specific match
• operational priority: whatever has high priority
• recency: use the more recent rule
• dependency: if the goal state depends on some sequence of state transition, follow rules that enable that sequence
• concepts: mental representation of a class of objects or events
• concept is multimodal (not just verbal description, but includes visual, auditory and other kinds of representations)
• what are the terms to describe new views of concepts?

  schema, frame, script
• schema: a structure of the related object/idea showing the constituent typical properties or features

  • does not represent the essence of a concept
  • includes kind (categories) and part hierarchies and other associated
  • a structured system capable of organizing and perceiving new informatio
  • may involve implications/rules to separate concepts
• frame: thinking should be understood as a frame of whole rather than by the structure or parts