Science and Psychology

Richard Wilton, Trevor Harley

• Publisher: Routledge
• Year: 2017
• Topic: Psychology
• eBook ISBN:
  9781315529271
• Subtopic: Epistemology in Philosophy
• Index: Psychology

Science and Psychology provides a comprehensive introduction to the structure and characteristics of scientific explanation, using examples from a variety of sciences to illuminate the scientific approach taken in psychology. In addition, the authors discuss a range of conceptual issues particular to psychology. They examine the concepts of free will, consciousness, and purposeful behaviour, and consider the social implications of possible future changes in our understanding of these concepts and of ourselves. The final chapters of the book provide an account of what psychology can tell us about the history and origins of science.

Assuming no previous understanding of either the philosophy of science or any science other than psychology, Science and Psychology is an ideal resource for both final year undergraduates and postgraduates studying psychology. Psychologists and other scientists who wish to further their understanding of the relationship between psychology and the natural sciences may also find the contents to be of interest.

Part 1
The characteristics of scientific explanation and its application to psychology

With some reservations, which will become apparent as we work through this part of the book, it could be said that the aim of science is to describe and explain the world in which we live. In the five chapters of Part 1, we examine, in detail, the characteristics of this process.

Before we begin, however, a comment is in order concerning the scope of the material. Much of the material is derived from work carried out in philosophy; and some of the examples used to illustrate various points are taken from sciences other than psychology, for example, physics. However, the book has been written on the assumption that the reader has no background in either philosophy or these other sciences. In addition, we, the authors, have chosen examples that can be simply explained and that are suitable for use on several different occasions in the book, thereby keeping their number to a minimum. We do not want readers to give up on a task which they might otherwise find interesting, and perhaps revealing, because they lack the relevant background in these areas. So do not feel daunted when you first encounter some philosophical term or an example of some effect from the non-psychological sciences. There are not many of them, and the same ones are used repeatedly throughout the book. The book was written specifically for readers who have a background only in basic psychology (although we hope and believe that even the scientists among you will learn a thing or two about science).

We should note also that, ideally, the book is best read as a novel is read – that is, begun at the beginning and ending at the end. We say this because what is said in most of the chapters (particularly the ones in Part 1 of the book) presumes an understanding of what was said in previous chapters. And, like a good novel, we hope that reading the book will result in an expansion of your horizons.

Chapter 1
The defining characteristic of science

In later chapters of this part of the book, we shall discuss in detail the characteristics of scientific explanation, including, for example, theories and laws. However, before we become fully immersed in this, we shall, in this short but essential chapter, focus on the single most important and defining characteristic of science, which is that any statement made in science must be open to test by observation of the world, thereby enabling one to gather information about its truth or falsity. Let’s see what this means.

Consider the following statement: if you stroke this cat, it will purr. Now, suppose that Jones and Smith differ as to whether they believe the statement is true. All they have to do in order to find out whether it is true or false is stroke the cat and observe whether it purrs or not. By saying that they can observe whether or not the cat purrs, we mean they can use their eyes, ears, and other sensory organs or instruments (a microphone perhaps, or a video camera) to determine whether or not the cat purrs. If they observe that it purrs, they have discovered that the statement is true; if they observe that it does not purr, they have discovered that it is false.

Not all statements are open to test by observation; hence, to say that a statement is a scientific one is to say something in particular, namely that its truth or falsity can be tested by observation. To illustrate this, consider the following example of a statement that could not be included within science: “It is wrong to keep animals locked up in cages.” Here there is no observation that a person can make in order to find out whether this statement is true or false. All anyone can do is say what his or her own beliefs are concerning what is right or wrong, and in that context, say whether they believe the statement is true or false. To illustrate: suppose Jones believes it is wrong to keep animals in cages, and Smith believes it is not wrong. This difference in beliefs could obtain even though each of them has made all the observations that could be relevant to what they believe, for example, whether the animal shrieks and scratches at the bars of the cage, and even whether or not they accept that the animal suffers as a result of being caged.

For clarity, note that we are not here denying that the statement “It is wrong to keep animals locked up in cages” is false, and we are not denying that it is true. Rather, we are saying that whether it is true or false cannot be discovered by observation. We might be able to establish its truth or falsity by argument from moral principles, but such an argument would not be a scientific one.

The above should also make us realise that, since not all statements are scientific statements, science cannot tell us everything that we might want to know. For a further illustration of this point, consider a confusion that often occurs in discussion of morality and evolution. Evolution may have made us selfish and aggressive, caring for our own family at the expense of others (say). And because our disposition to behave selfishly and aggressively is a result of evolution, we might say that this is our natural way of behaving. However, to show that it is natural to behave in some particular way implies nothing whatsoever about whether it is morally right to behave in that way. In other words, it may be true that we are disposed to behave in some particular way, and that we can discover that this is so by observation; but in itself, this implies nothing about how we should behave (i.e. nothing about the rightness or wrongness of behaving in this way). Similarly, although some behaviour may be unnatural in that it has not been selected in the process of evolution, this unnaturalness does not imply that it is wrong (and neither does it imply that it is right). Thus, for example, one could believe that homosexual behaviour is unnatural, in the sense described, and also believe there is nothing wrong with it. The morally right way to behave cannot be deduced from any assertion about evolution.

The argument being made here was first put forward by David Hume (an 18th-century philosopher – see Ayer, 1980), who pointed out that one cannot get an “ought” from an “is”. That is, one cannot make a deduction as to how one should (ought to) behave from some observation concerning how one is disposed to behave.

Given the preceding discussion, it may be worth noting that some people believe that one can discover the truth or falsity of statements about what is morally right or wrong by a means other than observation, for example, through revelation from God or consultation of a book such as the Bible. This sort of claim is of no concern to us here, since we are concerned only with science, so we will not discuss it further. However, in other contexts – for example, the discussion of various issues concerning comparisons between science and religion – you might find it useful to bear the distinction in mind in order to avoid confusion about what can and cannot be claimed in science.

Test your understanding of Chapter 1

In a teaching course based on the contents of this book, students were examined upon their ability to answer some questions. The students were given one hour to answer each question, and were not allowed to consult any notes. We thought you, also, might try your hand at answering these questions in order to discover whether you (really) do understand the material. If you are taking a course which uses this book, the course instructor could set and mark your answers. Alternatively, you could write your answer and ask some other person to read it in order to see whether your answer makes sense. We might note also that the perennial advice that lecturers give in answering questions is to read the question carefully and actually try to answer the question as set, rather than some other question which you can readily answer, but unfortunately has not been set! Our procedure, at the end of each chapter, will be to set questions relevant to that chapter.

Having said all this, we have only one question for Chapter 1; our excuse is that the chapter is only a short one. Here is the question.

1. What distinguishes scientific statements from non-scientific statements?

Chapter 2
The structure of scientific explanation

The Standard View

In Chapter 1, we said that the aim of science is to describe and explain the world in which we live. Most importantly, within this context, we then said that the hypotheses we might have about the world must be open to test by observation. It is this ability to test hypotheses that distinguishes the scientific enterprise from other attempts to describe and explain the world.

In the remaining chapters of Part 1, we shall engage in a detailed examination of scientific description and explanation. Two different analyses, called the Standard View and the Alternative View, will be considered. Both views accept the primary importance of statements being open to test by observation, and also have much else in common. However, as we shall see, the two analyses differ in one fundamental respect and, in consequence, have very different implications for what can be claimed in science.

Before we do this, however, it is necessary to introduce some technical concepts which should assist our understanding throughout the book. It is essential for you to become sufficiently familiar with these so that you can wield them readily without too much thought. They are commonly used in the philosophical literature, and we believe them to be invaluable in our own presentation.

The first of these concepts is simple and has already been used. It concerns the definition of a statement. A statement (e.g. “John loves Mary”) is either true or false; by contrast, a meaningless concatenation of words (e.g. “loves, Mary, John”) is neither true nor false: in this case, the concepts of true and false are inapplicable.

The second concept concerns the meaning of the term ‘implies’. The meaning of ‘implies’ can be illustrated as follows: suppose A implies B. This means that if A is true, then B is true. That is, it would be a contradiction to suppose that A is true and B is false. Here are a couple of examples. The statement “All swans are white” implies that “This swan is white”. “John is a father” implies “John has a child”. Another way of saying that A implies B is to say that B can be deduced from A. Thus, if all swans are white, we can deduce that “This swan is white”. The words ‘implies’ and ‘deduce’ are both frequently used in the literature. Note that “A implies B” does not mean that B implies A (“All swans are white” means that if this thing is a swan, then it is white, not that all white things are swans).

A mistake easily made is to confuse the use of the term ‘inference’ with that of ‘deduction’. Suppose Robinson Crusoe discovers a depression in the sand that looks like a human footprint. And, perhaps because it is likely to have been caused by a human foot, he may infer that it was caused by a human foot. However, this does not mean that he has thereby deduced that it was caused by a human foot – for it is possible that it was caused by something else (for example, it may have been produced by the wind). Thus, to infer that something is the case is not to deduce that it is the case. Rather, it is simply to make an educated guess that it is so. Inference does not have the same meaning as deduction or implication. As a test of your understanding of the difference, ask yourself whether Sherlock Holmes actually did deduce (rather than infer) all that he was said to deduce.

The Standard View

Now let’s return to our consideration of the Standard and Alternative Views of description and explanation in science. We shall consider the Standard View first. Then we will argue that the Standard View is actually incorrect, and this conclusion will lead us to a consideration of the Alternative View. You might ask: why bother even to consider the Standard View, given that it is wrong? One reason is that many scientists and laypersons believe the Standard View to be correct, and on this basis, they incorrectly accept arguments, which appear to be convincing, about the degree to which we can be certain about the statements made in science; it is best to be aware of such errors in reading and listening to what others say about science. Another reason is that one must understand the Standard View in order to fully appreciate the different profound implications of the Alternative View. And yet another reason is that much of what will be said in this chapter applies also to the Alternative View, so do not skip it on the grounds that eventually we shall decide that the Standard View is wrong.

According to the Standard View (Bechtel, 1988, pp. 1–70; Hempel, 1966, Chapter 5; Nagel, 1961, Chapter 6), science consists of a body of known facts and the explanation of these. The known facts are described by what are called observation statements, and any explanation of these facts is expressed in statements which postulate laws and theories. Let’s consider the three kinds of statement in detail.

Observation Statements

Suppose we want to find out whether some individual object has some particular property. For example, suppose we want to know the colour of the swan that lives on our village pond. We go down to the pond, observe the swan and its colour, and write down the result of our observation – “The swan on the village pond is white” – in our notebook. What we have written down is called an observation statement. An observation statement is a statement that describes the result of an observation. It makes an assertion about some particular observed entity, such as the swan on the village pond. Another example would be “The poker by my fireplace is one metre in length”. A third example would be “The red billiard ball is five feet from the white billiard ball”.

It should be noted that the assertion made by the observation statement does not describe a defining characteristic of the object we are talking about. If it did, we would not have to make an observation in order to make the assertion. Rather, the statement reports a genuine discovery about the world. One observes the swan (defined, say, by its size and shape or whatever), which, as far as anyone knows before making the observation, could be either white or not white, and discovers that it is white. We do not need to go to the village pond in order to be able to write down “A swan is a bird”.

Contrary to what we have supposed, some readers might suggest that a swan is white by definition, and so could not be not-white. But, if so, then rather than argue about whether they are right or wrong in making this claim, we would simply avoid using “This swan is white” as an example of an observation statement – just as we would not use the example “This husband is married”. There is, we think, no need to discuss this further, for we believe it would be a diversion to do so in the present context. As should be clear, what we are concerned with, at present, is making and reporting discoveries about the world.

Supposedly, any observation statement is incorrigible, which means that its truth is not open to doubt. Put another way, the statement always constitutes a faithful record of what one has observed. Thus, it is supposed that an observation statement cannot later be shown to be false by reference to any other discovery one might make. As will shortly become apparent, according to the Standard View, this characteristic of observation statements is one of great importance.

Consistent with what has been said above, in daily life we often speak of facts as states of affairs which can be stated independently of any interpretation (explanation) of them. “Just give me the facts” we say. Hence, as should be apparent, observation statements are, according to the Standard View, statements of fact. It is often said that scientists like to express their findings in terms of facts. Then everyone can agree on ‘what is’ and then perhaps argue about what laws or theories might explain the facts.

Now, continuing with the Standard View, let us examine the two kinds of statement (ones that express laws and theories) that are used to explain the facts. As we shall see, an important characteristic of both these kinds of statement is that they go beyond the observed facts in that they might be shown to be false by observations not yet made. Neither of these two kinds of statement can therefore be demonstrated to be true: they are not incorrigible.

Statements that Assert Laws

A statement of a particular law asserts that all the observable entities of a particular kind (whatever their location in space and time) have a particular property. For example, “All swans are white” is a possible law. Laws are usually formulated by scientists in the following manner: the scientist makes one or more observations of individual entities (e.g. one swan being white, then another, then another, and so on), and then generalises from these cases to make the claim “All swans are white.” It is sometimes thought that more than one observation must be made in order to formulate a law, but this is not so. Although it would be very unusual (for reasons we need not enter into here), a scientist might...

Table of contents

• Cover
• Title
• Copyright
• Contents
• Preface
• PART 1 The characteristics of scientific explanation and its application to psychology
• PART 2 Understanding behaviour
• PART 3 What psychology tells us about the practice of science
• References
• Index