System and science: studying systems and designing them

Describe or prescribe

Your book says knowledge is our understanding of the systems around and within us, and science is a systematic way to validate it. Science has two main types: natural science and design science.

Natural science studies existing natural systems to understand how they work. It is descriptive. Scientists follow the empirical cycle (Fig. 1.6): observation, question, hypothesis, experiment, analysis, conclusion.

Design science creates new artifacts (tools, systems, methods) to reach specific goals. It is prescriptive. Researchers follow the regulative cycle (Fig. 1.7): problem investigation, solution design, solution implementation, solution evaluation.

The book's forest example: studying how species in a forest interact is natural science. Developing software to manage forest data for conservation is design science.

Computer science uses both. Its natural-science side studies algorithms, such as QuickSort and MergeSort, to understand their speed. Its design-science side builds new tools, like a programming language, and improves systems, like a faster database.

Natural science describes what exists (empirical cycle). Design science prescribes and builds something new (regulative cycle). Computer science does both.

Key terms

Descriptive

The nature of natural science: understand and describe natural phenomena.

Prescriptive

The nature of design science: prescribe and create artificial systems.

Empirical cycle

Observation, question, hypothesis, experiment, analysis, conclusion.

Regulative cycle

Problem investigation, solution design, implementation, evaluation.

Short questions with model answers

1. Q1. How do natural science and design science differ? Use your book's forest example.

   • Aim.
   • Nature and cycle.
   • Forest example.

   One describes the forest as it is; the other builds a tool to help protect it.

2. Q2. Why does your book say computer science uses both methods?

   • Natural side.
   • Design side.

   It studies how computers work (natural) and builds better computing tools (design).

Common mistakes

• ✗ Calling natural science prescriptive and design science descriptive.

  ✓ Natural describes what exists; design prescribes what to build.

• ✗ Putting hypothesis and experiment in the regulative cycle.

  ✓ Those belong to the empirical cycle; the regulative cycle runs problem → design → implementation → evaluation.

• ✗ Saying computer science is only about building software.

  ✓ It also studies existing algorithms, which is its natural-science side.

MCQs

1. 1. The nature of natural science, as your book describes it, is:

   1. (a) Prescriptive
   2. (b) Descriptive
   3. (c) Regulative
   4. (d) Artificial
   Show answer

   (b) Section 1.3.1, p. 11.

2. 2. Which step belongs to the regulative cycle of design science?

   1. (a) Hypothesis
   2. (b) Observation
   3. (c) Experiment
   4. (d) Solution implementation
   Show answer

   (d) Fig. 1.7, p. 12.

3. 3. Designing a new programming language that makes secure programs easier is an example of:

   1. (a) Design science of computer science
   2. (b) Natural science of computer science
   3. (c) The empirical cycle
   4. (d) A natural system
   Show answer

   (a) Section 1.3.3.2, p. 12.

4. 4. Studying how different species in a forest interact is:

   1. (a) Design science
   2. (b) Software engineering
   3. (c) Natural science
   4. (d) A regulative cycle
   Show answer

   (c) Examples, p. 12.

5. 5. Analysing QuickSort and MergeSort to understand their speed belongs to:

   1. (a) Design science of computer science
   2. (b) Natural science of computer science
   3. (c) Social systems
   4. (d) Solution evaluation
   Show answer

   (b) Section 1.3.3.1, p. 12.

Quick revision

• Natural science is descriptive and follows the empirical cycle.
• Design science is prescriptive and follows the regulative cycle.
• Computer science uses both: it studies algorithms and builds better tools.