3 Sensing data and turning it into something usable

3.1 Making sensation make sense

In the previous section you learned something about what data is, where it can be found, and how it can be used. But have you ever thought about how we get data in the first place? As human beings, we are so used to reading, writing, speaking and observing that we rarely think about the true origins of the data we commonly use with such ease. I don't intend taking you back to these origins – that would take too long. Rather, I want to describe how human beings ‘get’ data and put it into a useful form.
This section aims to:

• provide a more detailed definition of data;
  


• show in simple terms how human beings can turn sensory data into something that can be communicated and reasoned about.
  

Before computers, it was mainly philosophers who thought about how human sensation (such as sight or hearing) could be turned into an abstract thing like thought (i.e. ideas or reasoning). To do this, most agreed, sensation had somehow to be transformed into an appropriate form. Once it had such a form, it could become the subject of thought, and human beings could reason about it.

Example 1

If you touch a surface, one of the things you will sense is its temperature, i.e. whether it is hot, cold or neither. This is a survival mechanism: if a surface is so hot, or so cold, that it will damage your hand, you need to remove it immediately. But between the extremes of damagingly hot or cold there are all sorts of other sensory experiences: uncomfortably hot, comfortably hot, comfortably warm, neutral, comfortably cool, and uncomfortably cold. Even these categories can be further divided.
If we were only able to react instinctively to our sensations of hot and cold, we wouldn't be able to convey anything about that surface to another person – for instance to warn them that the surface was damagingly hot or cold. So in the course of our evolution, we have developed the means of transforming sensation into a form that can be thought about and communicated. We have developed words like ‘hot’, ‘cold’, ‘warm’, and ‘cool’. Such words allow us to link one sensation (touch) to another (vision) (e.g. ‘as hot as burning coals’) and use them to convey our thoughts to other human beings who share our language.
But humans have also gone further. Languages have been given written form, which enables us to transmit our sensations and thoughts across time and space, so that someone over four centuries ago could write:

as, the icy fang
And churlish chiding of the winter's wind,
Which, when it bites and blows upon my body,
Even till I shrink with cold, I smile …
(Shakespeare, As You Like It)

and convey to us now the feeling of coldness.
Also, because science doesn't deal in words (such as ‘cold’) which are open to different interpretations, we have developed more objective measures of hot and cold, such as the length of a column of mercury in a thermometer. Thermometers can then be used to compare temperatures by dividing the column of mercury into gradations, called degrees Celsius (written °C). (I n some countries temperature is measured in degrees Fahrenheit.) So everyone will agree that a particular surface with a temperature of 112°C is hotter than one of 91°C, even though both may feel unbearably hot.

The remainder of this section looks at the concept of sensation, and how perceptions of sensation (such as feeling something is warm or seeing colour or hearing sounds) can be represented so that a computer can do something with them.