Revival: A Modern Introduction to Logic (1950)

Lizzie Susan Stebbing

• Publisher: Routledge
• Year: 2018
• ISBN:
  9781351349079
• Edition: 1
• Topic: Filosofia
• Subtopic: Storia e teoria della filosofia

As the author of this volume states, "the science of logic does not stand still." This book was intended to cover the advances made in the study of logic in the first half of the nineteenth century, during which time the author felt there to have been greater advances made than in the whole of the preceding period from the time of Aristotle. Advances which, in her eyes, were not present in contemporary text books. As such, this book offers a valuable insight into the progress of the subject, tracing this frenetic period in its development with a first-hand awareness of its documentary value.

A MODERN INTRODUCTION TO LOGIC

PART I

CHAPTER I

REFLECTIVE THINKING IN ORDINARY LIFE

‘Only connect.’—E. M. Forster.

LOGIC, in the most usual and widest sense of the word, is concerned with reflective thinking. We all constantly use the words ‘thinking’ and ‘thought’. So long as we are not asked to define them we feel confident that we know what these words mean. But we do not always use the word ‘thinking’ in the same sense. Sometimes we contrast “I think of” with “I am now seeing”. In this sense we are using “think” to denote our awareness of something not directly presented to sense. Thus anything that ‘passes through our heads’ is called a thought. For example, lying on the sea-shore on a hot sunny day, in an idle mood, we may have a train of thoughts, a set of more or less disconnected ideas passing through our minds. These thoughts may be intimately bound up with our present sense-impressions—the heat of the stones, the sound of the waves, the call of the sea-gulls. In such a mood we do not connect one thought with another; we are at the mercy of any sense-impression that may break in upon us. Suppose now that the idler on the rocks is aroused by such loud, insistent shouting that he recognizes ‘in a flash’, as we say, that this shouting has some peculiar significance for him. His reverie ended, he jumps up and looks around. Let us suppose that he now sees the water breaking on the rocks just below. He turns round to find that the rock on which he is standing is completely cut off from the shore in front. Behind is a steep, overhanging cliff, which he could not scale. The tide will soon completely cover the place where he has been lying. He cannot swim. What is he to do? He supposes that the people on the cliff, who shouted to him, have probably realized his situation. He wonders whether they can help him. Looking up he sees that some one is pointing to the face of the cliff. Does that mean that there are footholes? He looks, but can find none. Then he observes above his head a narrow projection of cliff. If he could clamber on to that perhaps he would be out of reach of the incoming tide. Would that be so? Again he looks, and sees that just below the ledge there is the dark brown discolouring of the rocks that is the mark of high tide. That ledge, then, will be safe, if he can reach it.

In the above situation we have a concrete illustration of the contrast between unreflective and reflective thinking as the latter occurs in ordinary experience. At first the man was not attending to his sense-impressions; nor was his thinking consciously controlled. But as soon as he was conscious that the situation was one of danger he was confronted with a problem to be solved. Consequently, he was forced to think about the situation so as to alter it in accordance with his practical needs. He becomes aware of the sea as menacing; he not only sees the water near his feet, he sees it as a sign of danger because he interprets it as signifying ‘retreat to shore cut off’. Similarly, he not only hears people shouting; he interprets their shouts as having special meaning for him. He not only sees the various shades of brown on the face of the cliff, he interprets them as signs of high tide level. Suppose now that he asks himself the question whether the tide is likely to rise above the normal level to-day. He considers that last night the moon was in its first quarter; therefore, it will be a neap tide; hence, if he can reach the ledge he will be safe. In this last stage of his reflective thinking he is obviously relying upon previous knowledge of facts relevant to the situation. He remembers that the moon was at its first quarter the night before; he knows that a neap tide is connected with the moon in that position, he infers that the tide will not rise high to-day. In this process of thinking directed to a practical end it is unlikely that the thinker will consciously use words. He may have merely a visual image of the appearance of the moon as he saw it yesterday, and pass directly to the reflection—‘a neap tide’, and thence, to the conclusion : “So that’s all right.” The remembered appearance of last night’s moon is thus directly interpreted as signifying what he wanted to know.

Suppose that, once he is perched on the ledge, the man looks about him to distract his thoughts. He sees on the other side of the cove, some way up in the side of a rocky headland that juts into the sea, a wide opening, not previously noticed, or taken to be a natural cleft in the rock. Now that his attention is directed to it, he sees that the opening is not the entrance to a cave, for he can discern bricks cemented together. Taken in itself there is nothing startling in a brick wall, but in this situation its discovery suggests the question how a brick wall came to be there. It can’t be the remains of a house, for it is about half-way up in the side of a steep cliff below which the tide never goes out. The headland is seen to be connected with the mainland by a narrow ledge of rock more than a hundred feet high. He knows that on the top of the headland are the ruins of a castle which is supposed to have been King Arthur’s. Perhaps the brick wall was once right inside the rock, the face of which has now fallen away. That is a reasonable supposition, for it is a stormy coast and rocks that have evidently fallen are piled below. In that case, however, the bricked chamber would have had no outlet to the light. Perhaps it is a secret chamber, or a dungeon. In that case it is probable that there will be some connexion with the mainland—perhaps a secret underground passage. At this point of his reflection, he must perforce cease his questioning. In his present position he has no means of testing his suppositions. Next day he may proceed to test the correctness of his theory with regard to the brick wall. On investigation of the headland he finds a disused shaft which he calculates to be in the right position to connect with the chamber. He discovers a not unsimilar shaft on the main cliff, near the church. He reflects that a passage running from the one shaft to the other would pass beside the brick wall, and connect the underground chamber with the church. At this point he will feel that he has accounted for the brick wall in the cliff.

Simple as these two illustrations are, they suffice to show how thinking essentially consists in solving a problem. The first was a practical problem, namely, how to reach a place of safety. The second was a problem arising out of the perception of something unexpected in a familiar situation. In this case the solution of the problem was sought merely for its own sake, in order to answer the question, “Why is so-and-so such-and-such?”—a question asked only when the such-and-such has features that would not be expected to occur in the given situation. The occurrence of these unexpected features is felt to be explained as soon as they are related to a situation in which their occurrence would not be unexpected. The explanation consists in finding intermediate links that connect the brick wall and the cliff. It is reached as a process of reflective thinking in which each link, brick wall, disused shaft, castle, church, is attended to not for its own sake but as being a sign of something else. Such a process of reflective thinking is known as inferring. In this case there was a passage from something sensibly presented to something not presented but inferred, which may, or may not, be the case. To determine whether it is the case, or not, the inference must be further tested. Such testing may be carried out in two widely different ways. The inferred conclusion may admit of direct inspection. In this case, the test would consist in verifying the conclusion by direct observation of something presented to sense. Clearly it is not always possible to perform such a test as, for example, in our illustration, which was concerned with a question about a state of affairs in the past. In such cases the conclusion is tested by its power to connect together various observable items which, apart from the supposed connexions, would remain disconnected.

We have spoken of ‘directly observing something’. But what we directly observe, see with our eyes, for instance, is a very small part of what we observe when we say that we are perceiving so-and-so. Thus, for example, in looking at a puzzle picture where a man’s head is suggested by the lines drawn to indicate the leaves of a tree, we suddenly discover the head. Knowing what we are in search of we attend to some only of the lines drawn and actively connect them with others, finally making out of the set of lines attended to the representation of a man’s head. No hard and fast line can be drawn between what is actually seen and what is suggested by what is seen. We see what we have a mind to see. In the situations of everyday life our senses are being constantly stimulated by a variety of sense-impressions amongst which we have learnt to pay attention to some as being specially significant, that is as being signs of something else in which we are interested. When one thing signifies another, there is between them that connexion which enables us to pass in thought from the one to the other. The sun setting in a bank of clouds may be noticed merely for its shape and colour, and appreciated for its beauty. But it may also be apprehended as signifying wet day to-morrow. Again, waving a flag may be a sign of high spirits, or of a certain state of mind called patriotism.

Thinking, we have seen, essentially consists in solving a problem. The ability to think depends upon the power of seeing connexions. Reflective thinking consists in pondering upon a given set of facts so as to elicit their connexions. “I didn’t think” ...

Table of contents

• Cover
• Half Title
• Title Page
• Copyright Page
• Dedication
• Table of Contents
• PREFACE TO THE SECOND EDITION
• PREFACE TO THE FIRST EDITION
• PART I
• PART II
• PART III
• APPENDIX A. MEANING, REFERENCE AND DESCRIPTION
• APPENDIX B. LOGICAL CONSTRUCTIONS
• APPENDIX C. POSTULATIONAL SYSTEMS AND PRINGIPIA MATHEMATIGA
• APPENDIX D. THING AND CAUSE
• BIBLIOGRAPHY
• INDEX