Experimental Child Psychologist

Essays and Experiments in Honor of Charles C. Spiker

L. P. Lipsitt, J. H. Cantor, L. P. Lipsitt, J. H. Cantor

• Publisher: Psychology Press
• Year: 2013
• ISBN:
  9781134931491
• Edition: 1
• Topic: Psychology
• Subtopic: History & Theory in Psychology
• Index: Psychology

First Published in 1986. This is a collection of essays in honour of Charles C. Spiker due to his personal contribution to the field of experimental child psychology. Each of the contributions to this volume echoes in its way the proclamation that some of the best lessons learned were from Charlie Spiker.

1 Principles in the Philosophy of Science: Applications to Psychology

Charles C. Spiker

University of Iowa

INTRODUCTION

Science as a Method

This chapter deals with the general rules, principles, and procedures that are common to all scientific disciplines. In modern times, this system of information has become known as the philosophy or logic of science. The different scientific disciplines—e.g. physics, chemistry, psychology, physiology, anthropology, sociology, etc.—represent the division of labor that scientists have effected. Each discipline has staked out its own area with relatively little overlap among the several areas. Despite this division of labor, all disciplines use the same general method. It is the common aspects of scientific methodology with which this chapter is concerned. A description of the scientific method describes how scientists obtain, formulate, and organize new knowledge. It does not deal specifically with knowledge that has been obtained by the scientific method.

The goal of science is variously expressed as the explanation, prediction, or understanding of the natural phenomena that surround us. One purpose of this chapter is to discuss the meanings of the words “explanation,” “prediction,” and “understanding” and to show that the three goals are really the same.

Science achieves its goal through observations, the careful description of observations, the formulation of laws of nature, and the construction of theories. This chapter explains the criteria that scientists use in relating their observations to descriptive words. It describes the way in which laws are formulated and it displays the anatomy of scientific theories.

Scientists use both inductive and deductive reasoning. This chapter explains in considerable detail what each of these two types of reasoning involves and how they differ. In particular, the nature of deductive reasoning is exposed and the central role of deductive processes in explanation, prediction, and understanding is specified.

Since the time of Isaac Newton, the development of theory has been viewed as one of the highest achievements of scientific effort. This chapter recognizes the importance of theory by providing a careful analysis of its structure, a description of the logic of testing theories, and an example of a relatively simple, comprehensible theory.

Three Kinds of Knowledge

The analysis of the scientific method presented here is based on the idea that all knowledge can be divided into three categories. It is helpful to think of each category as consisting of a very large number of sentences, statements, or propositions. (In this chapter, “sentence,” “statement,” and “proposition” are used synonymously.) We can tell which category a statement belongs to by noting what we would have to do to determine whether that statement is true or false. In other words, the categories of knowledge are different because the truth or falseness of their statements are determined in different ways. The distinction among the three categories of knowledge should become clearer as we proceed. First, however, we need to clarify the notion of a sentence.

The Characteristics of a Sentence. In a technical treatment of the scientific method, a great deal would be said about the nature of sentences. Given our more modest purposes, we try to grasp the basic notion of a sentence with a few examples and a liberal use of intuition.

A sentence is a string of words. Not every string of words, however, is a sentence.

Napoleon, first, blue, difficult

The previous string is not a sentence, because it lacks grammar. All words in the string are familiar, meaningful English words. Nevertheless, they obviously do not constitute a sentence.

Spirotes girulate elatically.

This string of words seems to have the necessary grammatical structure. “Spirotes” looks like a plural English noun. “Girulate” has the form of many English verbs and “elatically” resembles an English adverb. Unfortunately, not one of the three words can be found in an English dictionary, and we would not count such a string as a statement.

Seventy-five percent of adult males have smudsy.

This is another string of words that appears to be a sentence; it also seems to have the necessary grammatical structure. There is one word in the sentence, however, whose meaning is unknown. Only if all words in the string are meaningful will we count a string as a sentence because we would otherwise not know how to determine if it is true or false.

There is one other type of word string that must be ruled out of the class of sentences for our present purposes:

Open the door.

Although such a sentence is grammatically correct, it does not make sense to assign a truth value to imperative sentences. So, imperative sentences will also be excluded from the class of sentences that make up the three kinds of knowledge.

In this chapter, “sentence,” “statement,” or “proposition” will be used to refer to those strings of words that are grammatically correct and contain only meaningful words. Most important, for a string of words to be a sentence, it must make sense to assign a truth value to the string.

The Characteristics of the Three Types of Knowledge. We can identify the class of knowledge a statement belongs to by considering what must be done in order to determine the truth value of that statement. Consider the following:

It is raining outside Seashore Hall right now.

To determine whether this statement is true, an observation must be made.

Now consider this statement:

Either it is raining outside Seashore Hall right now

or it is not raining outside Seashore Hall right now.

Is it necessary to make an observation about the conditions outside Seashore Hall? On the contrary, we know that this statement is true simply because we understand English. The key words in the sentence are “not” and “or.” There is nothing to see outside Seashore Hall that could possibly help us to assign a truth value to this statement.

Finally, consider the following statement:

It is very pleasant to walk in the rain.

Everyone knows individuals who would consider this statement false and other individuals who would consider it true. The truth value of the statement varies from person to person; such a statement, therefore, has no interpersonal truth value. It is not possible to assign truth values to such statements except in accord with the personal beliefs or preferences of particular individuals. It would not be reasonable to expect everyone to share these beliefs or preferences. Certainly, we do not expect everyone else to agree with the truth values that we, as individuals, might assign to such statements.

Let us now proceed to assign names to these three classes of knowledge. The first class is variously referred to as empirical, factual, or synthetic knowledge. Its distinguishing feature is that it is necessary to make observations, of something other than the sentence itself, to determine the truth value of the statement. The second class is called logical, formal, structural, or analytic knowledge. The truth of such statements is determined by analyzing the meanings of, and spatial patterns among, certain words that occur in the sentences. The third category is value knowledge. It consists of several subclasses—moral, ethical, esthetic, and societal laws. Statements in this class of knowledge do not have absolute interpersonal truth values. Their truth is relative, in the sense that the alleged truth values vary from society to society, from time to time in the same society, from individual to individual at the same time in the same society, and from one time to another for the same individual.

The foregoing paragraphs are designed to make it intuitively plausible that the distinction among three kinds of knowledge can be maintained. They do not constitute a fundamental, philosophical proof that there are three kinds of knowledge. Not all philosophers would accept the distinctions made here, although most philosophers concerned with the description of the scientific method would agree that these distinctions are highly useful in that description.

Another set of examples provides a test for comprehension of the trichotomy: (1) Ninety-nine percent of U.S. citizens say, “Sunsets are beautiful”; (2) sunsets are beautiful or sunsets are not beautiful; (3) Sunsets are beautiful. The first sentence requires observation to determine its truth value; indeed, a great many observations would be required to determine whether it is true. Hence, it is a statement of fact. Note that it is not necessary to know whether a statement is true before classifying it as factual. The term factual, as used here, refers to a statement, either true or false, that must be confirmed or disconfirmed by making observations. No observation beyond looking at the sentence is required to determine that the second statement is true; the meanings of “or” and “not” testify to its truth. Note that the substitution of “ugly” for “not beautiful” in the second sentence does not yield a sentence that is necessarily (logically) true, because there is at least one more category into which sunsets could fall—the mediocre category. The third statement is clearly a statement of value and lacks interpersonal truth value.

The Relation of Science to the Three Types of Knowledge. How does science relate to the three types of knowledge described previously? In one sense, the answer to this question is spread through the remainder of this chapter, but we can provide a preliminary answer at this point. The scientific method was developed to determine the truth value of statements from the empirical category. Knowledge from the logical category is used by scientists as an indispensable tool, although scientists, qua scientists, do not contribute to this knowledge. Science does not attempt to determine directly the truth value of any statements from the value category.

Science and Values. At this point, some readers may wonder whether science and value knowledge are really independent. Some may think that science does affect our values in important ways. For example, some of us have smoked cigarettes and have stopped after learning from scientific sources of an alleged relation between smoking cigarettes and several fatal illnesses. Did not science determine values for these reformed smokers? The answer is affirmative, but the effect was indirect. Science did not attempt to determine the truth value of the statement, “It is bad to smoke cigarettes.” The attempt was made to determine the truth value of the statement, “Cigarette smoking makes people ill,” which is a statement of fact. Individuals who believe the factual statement to be true may very well assign their own personal truth values to the former statement. Science, however, did not. Science does not even assign a truth value to the statement, “It is bad to die before you need to.”

If science does not attempt to determine the truth value of statements of value, who does? The answer varies from one society to another, from one segment of a society to another, and from one set of values to another. Thus, religious leaders have considerable influence on matters of morality; legislators and judges greatly affect legal prescriptions; musicians and artists provide important input with respect to esthetics; and the leaders of the various professions help to formulate ethical codes. Whether we like this way of determining values, these statements are a fair description of the way our society is structured with regard to values. Science affects human values only indirectly.

THE NATURE OF FORMAL KNOWLEDGE

To learn to fly an airplane takes many hours of practice. To become an airplane mechanic requires even more hours of study and practice. To design airplanes, one must know nearly everything the pilot knows, most of what the mechanic knows, and much more. Nevertheless, there is no need to become a pilot, a mechanic, or a designer in order to understand why an airplane flies. Similarly, it is not necessary to be a logician or a mathematician to understand the nature of logic.

The Role of Formal Knowledge in Science

Many readers will consider themselves to have a reasonably good grasp of the nature of empirical knowledge and a fair understanding of the scope and nature of value knowledge. At the same time, some of the same readers may hesitate to claim the same degree of comprehension of the nature of formal knowledge. In developing this section on formal knowledge, we show that formal knowledge consists of both logic and mathematics. The purpose, however, is not to provide training in either logic or mathematics, but instead to clarify the nature of this type of knowledge. Indeed, this material would have to be developed with a great deal more rigor to provide training in logic. While reading this section, some readers will discover that they already know a good deal about the rules of logic but still find it difficult to express this knowledge explicitly.

The Role of Logic in Laws and Theories. A great deal must be said about the nature of logic and mathematics before much can be said about the scientific method. This very fact is a testimony to the central role that formal knowledge plays in science. As we see in a later section of this chapter, laws of nature are formulated through induction. It is not even possible to fully understand the nature of induction without first understanding the nature of deduction—i.e., the nature of the logical process. As we see, a scientific theory is best described as a set of deductively connected empirical laws. So, a good grasp of the nature of deduction is required in order to understand what a theory is.

The Role of Logic in Prediction and Explanation. Scientists use the highly related terms, prediction, explanation, and understanding, with relatively restricted meanings. The scientific meanings of all these terms are best explicated by means of deductive (logical) schemata. Once the nature of formal knowledge is understood, a clear grasp of the meanings and implications of these terms is readily obtained. Conversely, vagueness about the nature of the logical process precludes more than a superficial understanding of these important concepts in science.

The Logic of Sentences (Sentential Logic)

Ideally, the words in a language can be divided into two classes—descriptive and logical. Descriptive words refer to things that are in the world, things as concrete as tables and chairs and things as abstract as honor and patriotism. Logical words do not refer to things in the world; rather they ar...