Measurements of physical parameters in sensory science
Measurement is the process of quantifying the extent or quantity of something by comparison with a •xed unit or a reference object of known size. It is the means by which we make objective comparisons between things on a consistent and reproducible basis, and provides a common language by which we can describe objects or behaviors. Measurement therefore sits at the heart of our modern technological world, supporting business, trade, industry, and science, and underpinning the regulatory framework that helps maintain and improve our quality of life, in areas as diverse as public health and safety, climate change, and sports and leisure. It is an essential part of all scienti•c and technological research and development, allowing us, for example, to specify the physical or chemical attributes of a substance or an object, to evaluate the activity of different parts of the brain, to quantify human perceptual responses and behaviors, to assess societal trends, or even (through the choice of an appropriate measurement method and scale) to enumerate such seemingly abstract qualities as intelligence or happiness. In the words of Lord Kelvin:
When you can measure what you are speaking about, and express it in numbers, you know something about it; but when you cannot measure it, when you cannot express it in numbers, your knowledge is of a meagre and unsatisfactory kind: it may be the beginning of knowledge, but you have scarcely, in your thoughts, advanced to the stage of science (as quoted in American Association for the Advancement of Science).