Knowledge in everyday life
Knowledge in everyday life

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Knowledge in everyday life

5.3 Objectivity and subjectivity, induction and deduction

The purposes of scientific enquiry are to describe, explain, predict and control (Reaves, 1992). Through scientific training, natural curiosity is developed into objective, empirical (experience-based) study involving observations and controlled experiments which constitute the methods of scientific enquiry that lead to scientific knowledge.

Activity 19: What do you know?

0 hours 20 minutes

First, think of something that you know about subjectively – for example, the town in which you live or a particular piece of music.

Then compare this to something that you know objectively – for example, the boiling point of water or who the prime minister is.

Make a list of the main similarities and differences between your objective and subjective knowledge.


You have probably been able to think of quite a long list of differences and very few similarities. Your differences may well focus on the notions of measurements and taking account of factual or verifiable observations. For example, you may know that water usually boils at 100 degrees Celsius because it is possible to test this experimentally and see that a thermometer registers 100 degrees once the water starts bubbling vigorously. Such objective knowledge would be described as reliable, replicable and generalisable: water is expected, under ‘normal’ conditions, to boil at this temperature, no matter who performs the test or how often the test is repeated. You probably know who the prime minister is because you remember the news the day after the election. In this instance, your ‘observation’ would be supported by the observations of millions of others.

On the other hand, subjective knowledge is more situated, particular and idiosyncratic: you may know certain parts of your town well, but you would not expect everybody to ‘see them in the same way’; you do not expect others to conform to your view even though some may. You may say that your subjective knowledge is valid but you do not expect to have it replicated or to be able to make generalisations from this understanding and position. Reaves (1992) gives the idea of honesty as an example of subjective knowledge. Most people would agree that honesty is all about integrity, fairness and morality; but how is it possible to measure, objectively, someone's level of honesty to show that one person is ‘more honest’ than another?

In practice, everything we know is a construct of the senses. We perceive the world around us and, through our senses, we construct meaning – a process that will always involve an element of subjectivity. Scientific method adheres to an objectivity paradigm because it wants to eliminate biases and idiosyncratic ideas from its body of knowledge. Therefore, all observations must be made more than once; they must usually be made using instruments rather than just the human senses; and, if possible, they should be made under various test conditions to see that the same reliable answers come up every time, thus ensuring scientific reliability.

Throughout this block we have argued that science is a particular way of knowing and speaking about the world; one way to find out what constitutes science, therefore, might be to investigate what scientists do and how they do it in order to create this particular way of knowing (Reaves, 1992):

The scientist postulates nothing of the world beyond sense [because] it is impossible to know what there is behind sense-impression, if indeed there ‘be’ anything.

(Pearson, 1900, pp. 179–81)

This is not the place to enter into philosophical debate about what ‘there “be”’ in the real world or, indeed, if anything exists outside human perception. For the moment, we must be satisfied that all empirical evidence comes to us through the senses and thus what ‘there “be”’ is real because we perceive it to be so. This, however, is one of the major stumbling blocks of scientific enquiry. Science demands objectivity and yet, paradoxically, all scientists use their subjective perceptions to perform their scientific work. Science must be objectively distanced from its object of enquiry so that its empirical measurements are robust enough to be considered valid and to form a scientific epistemology, or body of knowledge; but all scientists have fallible perceptions. Scientists overcome this problem through two methodological steps – inductive and deductive enquiry.

The inductive approach to science begins with an observation, then multiple observations enable scientists to make generalised statements. If there are enough supporting general statements then a universal statement, or law, can be postulated (a law is an explanatory theory that enables us to predict what will happen next).

Let's look at an example of inductive theorising. You see the sun rise one morning – this is a singular observation. You continue to observe the sun rise each morning, so you can now make a generalisable statement about sunrises. You still do not know under what conditions the sun will rise but, if you take a holiday in another part of the world, you can see that the sun rises in most places at intervals of roughly twenty-four hours – although at the poles, during the arctic winter, it may not rise at all. Now a universal statement, or law, can be made which develops a rationale that accounts for the sun rising each day over your home and in many other parts of the world, but for it not rising on a daily basis in all parts of the world. You now have a theory!

From this theory you can now reason when and in what direction the sun will rise tomorrow. This is deduced from theory alone – you no longer have to travel around the world observing the phenomenon. Deductive reasoning is logical and rational, and, because of this scientific knowledge, is deemed to be legitimate and robust – powerful even. Deductions are tested experimentally, adding further observations; but if the predictions are incorrect, then the theory will have been falsified and you will have to think again. This is how science operates. It is not a neat, linear, step-by-step acquisition of truthful, legitimate knowledge. Rather, it is more a case of one line of thinking being accepted by a significant number of people (achieving a consensus); then suddenly some part is falsified and everyone must start again, trying to discover an explanation that better fits the known facts. For example, according to popular legend, everyone once ‘knew’ that the world was flat and that ships would fall off if they sailed too close to the edge. We now know that the world is spherical and you won't fall off because gravity holds you to the planet's surface.

Although science appears to progress through small, incremental stages, it in fact goes through series of ‘revolutions’ interspersed by longish periods of ‘normal’ science (Kuhn, 1970). These revolutions are characterised by the abandonment of one previously long-held and cherished set of theories (the earth is flat), which is replaced by another, often contradictory set of theories that better fit the new facts (the earth is round). These protracted stages are important sociologically because the knowledge deemed acceptable is less to do with facts and evidence and more to do with what society allows to be investigated and openly discussed.


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