An example of the use of analogy in extending a scientific concept,
"These terrestrial limitations obviously beg the question of whether there is any more generaIised activity that we can call life. Biology in this respect is on a different basis from physics and chemistry in that it deals less with universals and more with contingents. It belongs to the kind of descriptive and interpretative studies we might more properly call 'graphies', including observational astronomy and geography. Whether there are some general characteristics, which would apply not only to life on this planet with its very special set of physical. conditions, but to life of any kind, is an interesting but so far purely theoretical question. I once discussed it with Einstein, and he concluded that any generalised description of life would have to include many things that we only call life in a somewhat poetical fashion. Any self-subsisting and dynamically stable entity- transforming energy from any source, or, as Haldane put it, 'any self-perpetuating pattern of chemical reactions', might be called 'alive' in this sense. The value of distinguishing it as an individual system or organism would only exist if the total phenomena persisted for a time appreciably longer than the periods or characteristic times of any internal processes it might contain. In this sense a galaxy or a star is alive, or, on a more terrestrial scale, a flame. Passing to a degree, of complication greater than the biological, we might talk of the life of a human culture or civilisation. All are characterised by birth, persistence and death."
J. D. Bernal (1951) The Physical Basis of Life, Routledge and Kegan Paul.
We do not usually consider stars, galaxies or flames as living beings in the same way as we consider a bacterium, an oak tree, or a horse as alive. Stars are commonly said by astronomers to be born, live and die. This seems to be a dead metaphor (that is, for astronomers these terms are almost technical terms, even if they may mislead novices).
Here Bernal goes beyond metaphor to spell out characteristics of living systems which by analogy can be applied to galaxies, stars, flames, and cultures.
- a self-subsisting and dynamically stable entity- transforming energy from any source / any self-perpetuating pattern of chemical reactions
- if the total phenomena persisted for a time appreciably longer than the periods or characteristic times of any internal processes it might contain
- characterised by birth, persistence and death
Read examples of scientific analogies
Many examples of science analogies are listed in 'Creative comparisons: Making science familiar through language. An illustrative catalogue of figurative comparisons and analogies for science concepts'. Free Download.
