1.2 Shared Reality and Modeling

Science is grounded in belief in a common, shared reality with some degree of regularity.

The Lesson in Context

In this lesson, we lay the philosophical groundwork for future topics by establishing a common set of assumptions and attitudes in science, namely, that the world is full of regular patterns that can be studied empirically, and that scientific knowledge is constantly evolving in light of new evidence.

1.1 Introduction and When Is Science Relevant

• Decision making relies on knowing the effects of each decision in the real world. Collective decision making thus relies on a collective understanding of the shared reality through the scientific method.

2.2 Systematic and Statistical Uncertainty

• Our understanding of the shared reality is never perfect, but is always improving. When it comes to measured quantities, it is possible and necessary to quantify the inaccuracy or imprecision in our description of the shared reality.

3.1 Probabilistic Reasoning

• Since every claim of fact is to some degree uncertain, each claim should be associated with a level of confidence, or a probability that it is correct.

5.2 Scientific Optimism

• Although the first step of a scientific attitude is to admit one's ignorance or the uncertainty in one's knowledge, it is still possible to make progress by successive iterative improvements.

6.1 Correlation and Causation

• One important aspect of the shared reality is cause and effect, which is studied in a series of future lessons on causation.

8.1 Orders of Understanding

• When constructing a model of a complex system, we need to abstract out the most important aspects of the system in relation to the question at hand. This requires understanding (or hypothesizing) the order of importance of various aspects of the system, so that only the top one(s) are considered.

13.2 Deliberative Polling

• A type of event that helps the public make better group decisions after being informed on the relevant (shared) facts about an issue.

Takeaways

Learning GoalsDefinitionsLecture DefinitionsExamplesCommon Misconceptions

After this lesson, students should

1. Understand that the self-correcting and ever-changing nature of science is a strength, not a weakness.
2. Feel optimistic about the capacity of science to help solve problems for societal and personal decision-making.
3. Understand the assumption of shared reality with regular patterns and the power of empirical evidence as a way to study this shared reality.
4. Appreciate that scientific knowledge is built more like a raft than a pyramid.
5. Understand the need for scientific modelling and how our knowledge of reality is necessarily expressed in terms of models.

It's easy for students to get hung up on philosophical minutiae or edge cases of what really is reality, or does it even exist. Try to pull students back to the main goal of making practical decisions in our lives or in society by using science to understand the assumed shared reality. We only need things to be as real as the table in the middle of the room, so one can walk around it and avoid hurting oneself.

Raft vs. Pyramid

Two different metaphors for scientific progress.

• The Raft

Every scientific claim is subject to question and reevaluation; we can use the rest of our scientific knowledge to question any one claim at a time, though we cannot question the entire edifice at once.

• The Pyramid

Science builds on fixed foundations to ever higher levels of knowledge.

Scientific Models

An activity with the aim making a particular part or feature of the world easier to understand, define, quantify, visualize, or simulate. This is often done by referencing it to existing and usually commonly accepted knowledge.

Assumption of Reality

Scientists assume an external reality, which is shared by and affects all people and has enough regularity to lend itself to induction. This external reality is what scientists seek to describe accurately.

Empirical Evidence

Science is based on appeal to empirical evidence, which is publicly accessible on the assumption of reality (although may require special instruments and/or expertise to acquire).

Evaluation of Models

The extent to which a scientific model is as useful tool for describing some real external thing. There are several features that determine the usefulness of a model.

• Ability to explain past observations.
• Ability to explain future observations.
• Simplicity or ease of use.
• Refutability and the ability to characterize our confidence in the model for a given problem.

Science vs. Decree

Science gains its authority from its self-questioning character, not from the concentrated power of individuals.

These are additional definitions that appear in the lecture but aren't deeply discussed in the discussion's lesson plan.

Realism vs. Idealism

Two different ideas for the construction of the physical world.

• Realism

We all inhabit a common reality, which has a structure that exists independently of what people think and say about it (except insofar as reality is comprised of, or is causally affected by, thoughts, theories, and other symbols). The structure of the world is regular, such that the patterns we observe are likely to hold in new contexts.

• Idealism

The physical world is dependent on the conscious activity of humans. Also called phenomenalism.

Scientific Realism vs. Anti-realism

Differing views for how the world is described by science.

• Scientific Realism

Science aims to provide a true description of the world, which is assumed to exist in a mind-independent fashion, and it often succeeds (or at least is approximates the truth).

• Anti-realist theories of science differ from one another. Among the views defended:

  • • Scientific theories can never "reach beyond" experience in what they say.
    • Perhaps scientific theories can make claims that reach further, but we can't ever expect to get claims of that kind right.
    • The objects of scientific study themselves do not exist in a truly mind-independent fashion.

Definition

Types of Metrics

Ways of converting some aspect of the world into something measurable and (often) numerical.

• Conventionalist Metrics

When an individual scientist or the scientific community at large define some metric to be correct by convention.

• Operationalist Metrics

When the truth of a metric is taken to consist of the operations involved in proving or applying it.

• Realist Metrics

When the truth of a metric isn't based on human choices, but instead on some real phenomena in the world at large.

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Useful Resources

Lecture VideoDiscussion SlidesHandouts and Activities

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Recommended Outline

Before Class

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During Class

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Instructions

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