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INTRODUCTION

Ingredients

Society	A group of humans living in close proximity who have come to some agreement about rules of conduct and how to behave over time.
Ethics	The study of what is “right” and what is “wrong” in a society. Dictionary: Moral principles (beliefs about what is right and wrong) that govern a person's behavior or the conducting of an activity.
Law	The structured and organized coding of rules of conducts in a society.
Artificial Intelligence	A field of research. The scientific pursuit of making machines with intelligence. Also used to label products (software, machines, ideas, theory) that use results from AI research. Many products (software, machines, theory, ideas) may result from AI research, but no all deserve the label “AI”.
Data	Result of a measurement.
Information	“Data with a purpose.” Structured measurements and their relations. Processed and prepared data. Data organized at more than one level of detail.
Correlation	Relation between two or more measurements of information. A measure of the repeated co-occurrence of two or more measurements. Some variables co-vary when changes in one variable are related with changes in the other, negative or positive.
Knowledge	Useful information. Information that can be used for various purposes.
Agency	The act of using knowledge to get stuff done.
Agent	The physical locus/embodiment of agency. A system that can sense and act in an environment to do tasks.
Causation	A relation between entities in the physical world that allows us to achieve goals and predict events.
Perception / Percept	A process (perception) and its product (percept) that is part of the cognitive apparatus of intelligent systems. It feeds on measurements.
Goal	A specification of a world sub-state. The resulting state after a successful change.
Task	A problem that is assigned to be solved by an agent.
Environment	The constraints that may interfere with achieving a goal.
Plan	The partial set of actions that an agent assumes will achieve the goal.
Planning	The act of generating a plan.

SCIENTIFIC CONCEPTS

Empirical Science (or just 'science')

Empiricism	The claim that “the world is its own best model” – that is, no matter what our preconceived notions of how the world works are, the world is the ultimate judge of how it works.
'Empiricism' the term	The term comes from Greek ('empeiria'), meaning “experience”. Descartes put it clearly when asking the question “How can I be sure that I exist?” when he answered with the no-famous phrase “I think, therefore I am”.
Empiricism in science	Modern science takes the idea of empiricism to its ultimate conclusion: Let's find the best way to create the most reliable way of creating trustworthy knowledge about the world.
Comparative experiments	…are the key form that this creation has taken, but in fact many other forms of reliable knowledge creation, besides controlled comparative experiments, are in use. The key to them is the systematic categorization and estimation of the uncertainty of the information they produce. By knowing these, the trustworthiness of the knowledge produced can be assessed, and appropriate action taken when the knowledge is used.
The Content of Scientific Knowledge	…is essentially rules about the causal behaviors and relations of things. Causality is a way to extract compact knowledge about any complex system that contains regularities. It works for the physical world because the physical world is highly regular.

What is a Theory? What is a Hypothesis?

Theory (isl. kenning)	“A set of statements or principles devised to explain a group of facts or phenomena, especially one that has been repeatedly tested or is widely accepted and can be used to make predictions about natural phenomena.” REF A theory is a relatively big explanation, covering several phenomena, often through a single principle, or a set of simple principles.
Occam's Razor	A good scientific theory cannot be simplified; it is the shortest and most accurate explanation of a phenomenon. Einstein is quoted as saying: “A theory should be as simple as possible, but not simpler”.
Hypothesis (isl. tilgáta)	Is a prediction about the relationship between a limited set of phenomena, typically formulated as measurable variables, as explained by a particular theory.

The Scientific Method: The Comparative Experiment (ísl. samanburðartilraun)

Identification, description and formalization of phenomenon	1. Observation and description of a phenomenon or group of phenomena.
Hypothesis (and null-hypothesis)	2. Formulation of an hypothesis to explain the phenomena. In physics, the hypothesis often takes the form of a causal mechanism or a mathematical relation. Null-hypothesis of a hypothesis is the claim that it is false - i.e. that some relationship that it proposes does not hold.
Creation of experimental setup to test hypothesis	3. Use of the hypothesis to predict the existence of other phenomena, or to predict quantitatively the results of new observations.
Perform experiment; collect & analyze results	Performance of experimental tests of the predictions by several independent experimenters and properly performed experiments. Basic assumption: Repeatability – Can be repeated by anyone anywhere.
Repeatability requires formal framework	Detailed description, clear goals, clear (limited) scope, hence the formalities in their execution.
Key idea: Comparison	Baseline collected in same experimental setup without any other intervention by experimenter.
Key way of comparing	Empirical experiments.
Bottom line	Scientific research is a slow and expensive process. But it's the best one we've got (so far). And it's completely worth it.

Causation

What it is	A relation between entities in the physical world that allows us to achieve goals and predict events.
Why it's important	The comparative experiment (“the scientific method”) is based on the assumption that such relations exist, i.e. that the world has regularities.
How it relates to logic	If causal relations are rules, and the world has regularity, then the world is rules-based. Reasoning is the method of following logic when working with rules. It means we can reason about the world.
Types of (basic) causal relations	A→B & A→C : A causes B and C. A→B→C : A causes B and B causes C [A+B]→C : A and B together cause C. A→C, B→C : Both A and B are sufficient to cause B.
Time and Causation	The temporal relation between cause and effect is strict on time: Effects cannot happen before causes.

Scientific Method: Independent of Topic

Phenomenon	The world is filled with “stuff”. Anything is a “thing” - even “nothing” is a thing (a concept in our minds, which is represented as neural patterns and potential for behavior). We can group any arbitrary collection of things and call it a phenomenon. Example: A rock. A mountain. A planet. (If I say that I want to study “thingamajigs” - something you've never heard of - I will first have to list some of the major ways in which thingamajigs can be identified. In fact, this is a good idea anyway, so as to be clear and consistent about what it is that one is studying.)
The scientific method is independent of topic…	One can study any phenomenon with the scientific method, including claims of telepathy; selection of topic is independent of method – there is nothing inherently “unscientific” about studying any subject. (Close-mindedness is, however, very unscientific.) In other words, given that science gets us the most reliable (“best”) knowledge to build on at any time, we should take it seriously. But not so seriously as to exclude the possibility that it's wrong. (Because in fact we already know that all scientific knowledge is wrong – i.e. every scientific theory to date has limits to its scope that we know of.)
How can we trust our knowledge?	The scientific method is a General Way of Producing Trustworthy Knowledge. It is independent of topic. Therefore, it can also be used for AI systems. (In fact, it can easily be argued that something very similar to the scientific method is happening when humans learn cumulatively – with a few caveats that we will carefully cover in this course.)
Deduction	The cognitive act of following preconceived rules to their inevitable implication. Example: All men are mortal. Socrates is a man. Hence, Socrates is mortal.
Induction	The cognitive act of generalizing from experience. Example: Socrates is a man. Socrates died. Hence, all men will die.

Theories of the Scientific Method (Philosophy of Science)

Scientific Theories	The most powerful method by which science advances. By proposing a theory of a phenomenon, a scientific theory provides a holistic “story” about the relation between known parts of a phenomenon, and sometimes predict the existence of others unknown ones.
A Scientific Theory Explains	The main function of a scientific theory is to explain. If a theory of phenomenon X doesn't explain all the known facts about X, then it is incomplete. All scientific theories to date are incomplete in some way, but some more than others. Worse theories are discarded for better ones. Example: The atomic theory of matter was chosen over the theory that proposed the world was made of four elements: water, earth, wind and fire. The more completely and the more simply a theory explains things, the better it is.
A Scientific Theory Predicts	Since a scientific theory explains, it can also predict. A theory that predicts more unknown things than another is often considered a more powerful one.
“Just a Theory”	Sometimes people dismiss a scientific explanation because it is “just a theory”. This mistake stems in part from the fact that the term “theory” is used for both very simple and early theories (Earth, Wind, Water & Fire) and vastly more broad and reliable ones (like Einstein's theory of relativity).
A scientific theory is a spotlight	A good scientific theory tells us where to look for interesting things; the more detailed the theory the more detailed should be its predictions and the more narrow its spotlight (specific suggestions for new investigations).
A Scientific Theory Produces New Hypotheses	A good scientific theory helps us do more experiments by being a source of hypothesis creation.
A Scientific Theory Provides Control	A good scientific theory gives us control over the phenomenon it addresses that we would otherwise not have.
A scientific theory explains (“tells a coherent story”)	A good scientific theory explains how data are related.
A Scientific Theory Gives the Bigger Picture	A good scientific theory relates together, in a coherent way, some part of the world – in general the bigger the part, the better the theory.
A Scientific Theory can be disproven	To count as “scientific” a theory must be disprovable. For this there must exist some measures and actions that are possible (in theory, but better yet, practice) whose results would possibly – should the measurements come out a particular way – disprove the theory. Applying this criterion strictly means that all scientific theories to date have been disproven – i.e. proven incorrect (another way to say this is that we can find the limits* of a theory through experimentation).* This is a feature of science (not a bug): Exposing the limits of our theories by demonstrating in which contexts they are incorrect allows us to come up with better theories.

Fields of Research

Philosophy	A systematic investigation into any phenomenon. Fundamental motivation: Deepened understanding of our place in the universe. Fundamental driving principle: Human reasoning and creativity. Fundamental organizing principle: Schools of thought; methods of reasoning. When you hardly know anything about a phenomenon, yet insist on getting to the bottom of it, philosophizing gets you started.
Science	A systematic investigation into phenomena in the natural world susceptible to physical experimentation. Fundamental motivation: Reliable knowledge of the world. Fundamental driving principle: Induction. Fundamental organizing principle: Controlled comparative experiment. When you embark on improving your understanding of a phenomenon with measurable/quantifiable variables, through comparative experiments, you are applying the scientific method (“doing science”). “Expanding the model for deepening knowledge.”
Engineering	Effort to construct things using relevant knowledge (often state-of-the-art scientific models/theories - see below), systematic methods, and relevant technology. Fundamental motivation: Control of human environment. Fundamental principle: Design. Fundamental organizing principle: Methodical application of known procedures and methods. When you embark on changing or improving any aspect of your environment, working towards the implementation of a well-defined end product, through an application of best known practices, you are doing engineering.
Technology	The output of engineering. Methods, aparati, and techniques for getting things done. Fundamental principle: Composition, design, engineering. “Applying the model to get things done.”
Cognitive Science	The study of natural intelligence, in particular human (and that found in nature).
Mathematics	A systematic study of quantity, numbers, patterns, and their relationships. Fundamental principle: Deduction. When you embark on clarifying the behavior and nature of quantifiable domains, using axiomatic rules and proofs, you are doing mathematics.
Causal Relations	A relation between two entities that makes one predictable from the other. Deduction (deriving side-effects): If I flip the light switch, the lights will shine. Abduction (bringing about change): If I want the light to shine, I can flip the light switch.

Center for Analysis and Design of Intelligent Agents

Table of Contents

INTRODUCTION

Ingredients

SCIENTIFIC CONCEPTS

Empirical Science (or just 'science')

What is a Theory? What is a Hypothesis?

The Scientific Method: The Comparative Experiment (ísl. samanburðartilraun)

Causation

Scientific Method: Independent of Topic

Theories of the Scientific Method (Philosophy of Science)

Fields of Research