Related Experiment Video
Updated: Jul 10, 2026

The Use of the Puzzle Box as a Means of Assessing the Efficacy of Environmental Enrichment
Published on: December 29, 2014
Four puzzles about life
1Reed College, 3203 SE Woodstock Blvd, Portland, OR 97202, USA. mab@reed.edu
Abstract:
To surmount the notorious difficulties of defining life, we should evaluate theories of life not by whether they provide necessary and sufficient conditions for our current preconceptions about life but by how well they explain living phenomena and how satisfactorily they resolve puzzles about life. On these grounds, the theory of life as supple adaptation gets support from the natural and compelling way it resolves the following four puzzles: (a) How are different forms of life at different levels of the vital hierarchy related? (b) Is there a continuum between life and nonlife? (c) Does life essentially concern a living entity's material composition or its form? (d) Are life and mind intrinsically connected?
Related Concept Videos
Characteristics of Life
Solving Problems in Physics
Requirements for Human Life
Oxygen
Atmospheric air is only about 20 percent oxygen, but that oxygen is a key component of the chemical reactions that keep the body alive, including the reactions that produce ATP. Brain cells are susceptible to a lack of oxygen because they require a...
Theorems of Pappus and Guldinus: Problem Solving
Natural and Artificial Concepts
Problem-Solving

