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27 chapters
INTRODUCTION
INTRODUCTION
It has been suggested that some reference, of an apologetic nature, to the title of this book may be desirable, so I wish to point out that it can really be justified. Science, says Driesch, is the attempt to describe Givenness, and Philosophy is the attempt to understand it. It is our task, as investigators of nature, to describe what seems to us to happen there, and the knowledge that we so attain—that is, our perceptions, thinned out, so to speak, modified by our mental organisation, related
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CHAPTER I THE CONCEPTUAL WORLD
CHAPTER I THE CONCEPTUAL WORLD
Let us suppose that we are walking along a street in a busy town; that we are familiar with it, and all the things that are usually to be seen in it, so that our attention is not likely to be arrested by anything unusual; and let us further suppose that we are thinking about something interesting but not intellectually difficult. In these circumstances all the sights of the town, and all the turmoil of the traffic fail to impress us, though we are, in a vague sort of way, conscious of it all. El
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CHAPTER II THE ORGANISM AS A MECHANISM
CHAPTER II THE ORGANISM AS A MECHANISM
We propose now to consider the organism purely as a physico-chemical mechanism, but before doing so it may be useful to summarise the results of the discussions of the last chapter. Let us, for the moment, cease to regard the organism as a structure—a “constellation of parts”—and think of it as the physiologist does: it is a machine; it is essentially “something happening.” What, then, is the object of its activity? Whatever else the study of natural history shows us, it shows us this, that the
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CHAPTER III THE ACTIVITIES OF THE ORGANISM
CHAPTER III THE ACTIVITIES OF THE ORGANISM
The rather lengthy discussion of the last chapter was necessary in order to show just how far the principles of energetics established by the physicists applied to the organism. We have seen that the first law of thermodynamics does so apply with all its exclusiveness. The more carefully a physiological experiment is made; the more closely do its results correspond with those which theory demands. It is true that relatively few experimental investigations can be controlled in this way, but in th
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CHAPTER IV THE VITAL IMPETUS
CHAPTER IV THE VITAL IMPETUS
Two main conclusions emerge from the discussions of the last three chapters: (1) that physiology encourages no notions as to a “vital principle” or force, or form of energy peculiar to the organism; and (2) that although physiological analysis resolves the metabolism of the plant and animal body into physico-chemical reactions, yet the direction taken by these is not that taken by corresponding reactions occurring in inorganic materials. From these two main conclusions we have, therefore, to con
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CHAPTER V THE INDIVIDUAL AND THE SPECIES
CHAPTER V THE INDIVIDUAL AND THE SPECIES
What is an individual organism? A Protozoan, such as an Amœba or a Paramœcium , is a single cell: it is an aggregate of physical and chemical parts, nucleus, cytoplasm, etc., and no one of these parts can be removed if the organism is to continue to live. The cell can be mutilated to some extent, but, in general, its life depends on the integrity of its essential structures, and it cannot be divided without ceasing to be what it was. It contains the minimum number of parts which are necessary fo
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CHAPTER VI TRANSFORMISM
CHAPTER VI TRANSFORMISM
The species is therefore a group of organisms all of which exhibit the same morphological characters. This sameness is not absolute, for the individuals composing the species may vary from each other with respect to any one character. But the range of these variations is limited. They fluctuate about an imaginary mean value which remains constant in the case of a species which is not undergoing selection, and is therefore nearly the same throughout a series of generations. The formal characters
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CHAPTER VII THE MEANING OF EVOLUTION
CHAPTER VII THE MEANING OF EVOLUTION
Apart from experimental investigation, the results of comparative anatomy, even if they are amplified by those of comparative embryology, and even if they include fossil as well as living organisms, do no more than suggest the occurrence of an evolutionary process. It is in vain that we attempt a demonstration of transmutation of forms of life by showing that a similarity of structure is to be observed in all animals belonging to the same group. We may show successfully that the skeleton of the
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CHAPTER VIII THE ORGANIC AND THE INORGANIC
CHAPTER VIII THE ORGANIC AND THE INORGANIC
It is convenient that we should express the results of biological investigation in schemes of classification, for only in this way can we reduce the apparent chaos of naturally occurring organic things to order, and state our knowledge in such a way that it can easily be communicated to others. But we must always remember that the classifications of systematic biology are conceptual arrangements, depending for their precise nature on the point of view taken by their authors. The clear-cut distin
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INFINITY
INFINITY
What is really meant when the mathematician uses the concept of infinity in his operations? Suppose that we take a line of finite length and divide it into halves, and then divide each half into halves, and so on ad infinitum . We make cuts in the line, and these cuts have no magnitude, so that the sum of the lengths into which we divide the line is equal to the length of the undivided line. We can divide the line into as many parts as we choose, that is, into an “infinite” number of parts. Supp
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FUNCTIONALITY
FUNCTIONALITY
If we pour some mercury into a U-tube closed at one end, the air in this end will be contained in a closed vessel under pressure. We can increase the pressure by pouring more mercury into the open end of the tube. We can measure the volume of the air by measuring the length of the tube which it occupies. We can measure the pressure on this air by measuring the difference of length of the mercury in the two limbs of the tube. By taking all necessary precautions we shall find that for each value w
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THE NOTION OF THE LIMIT
THE NOTION OF THE LIMIT
But the reasoning would be faulty. The line ff 1 only touches the curve, it does not coincide with an element of the curve. Also at the point b 1 the pressure has a certain definite value, and there is no change. At the corresponding point b 11 the volume also has a certain definite value, and there is no change. There can therefore be no rate of variation. The value of the tangent does not give us a measure of the rate of variation: it gives us the limit to the rate of variation, when the press
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FREQUENCY DISTRIBUTIONS AND PROBABILITY
FREQUENCY DISTRIBUTIONS AND PROBABILITY
Let the reader keep a note of the number of trumps held by himself and partner in a large number of games of whist (the cards being cut for trump). In 200 hands he may get such results as the following: No. of trumps in his own and partner’s hands —0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13. No. of times this hand was held —0, 0, 0, 1, 9, 29, 53, 52, 35, 14, 6, 1, 0, 0. He should note also the number of times that trumps were spades, clubs, diamonds, and hearts: he will get some such results a
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MATTER
MATTER
Our generalised notion of matter is that it is the physical substance underlying phenomena. Immediately, or intuitively, we attain the notion of matter because of our perceptions of touch, and our perception of muscular exertion. The distance sense-receptors, visual, auditory, and olfactory, would not give us this intuition of matter. Material things are extended, that is, they have form, and they exclude each other, so that they cannot occupy the same place. They appear to us to be aggregates o
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MASS
MASS
When matter is perceived by the tactile and muscular sense organs, we have the intuition of mass. It is heavy , and the degree of heaviness is proportional to the quantity of matter in the body which we feel, that is, to its mass. Heaviness is synonymous with weight, but weight does not depend alone on the quantity of matter in the body. If the latter were removed to an infinite distance from the earth or other cosmic bodies, its weight would disappear, but its mass would remain. We could still
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INERTIA
INERTIA
If the body were in motion, we should find that muscular exertion is necessary in order that it might be brought to rest; and if it were at rest, we should find that muscular exertion was necessary in order that it might be moved. The body, matter in general, possesses inertia, and this is its most fundamental attribute. Mass we can only conceive in terms of inertia. If two bodies were at rest, and if the same degree of muscular exertion conferred on each the same initial velocity of motion, the
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FORCE
FORCE
The feeling which we experience when we move a body from a state of rest, or stop a body which is moving, is what we call force. If on climbing a stair in the dark we think there is one step more than there is, and so have the queer, familiar, feeling of treading on nothing, we have the intuition of energy; but when we tread on the steps, and so raise our body, we have the intuition of force. Force is that which accelerates the velocity of a mass. If the latter is at rest, we consider it to have
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ENERGY
ENERGY
Energy is therefore indefinable. It is an elemental aspect of our experience. Nature to us is an aggregate of particles in motion. We have to speak of massive particles, whether we call these visible material bodies, or molecules, or atoms, or electrons, in order that we may describe nature. We must employ the fiction of a substantia physica . We only know the substance or matter in terms of energy; it is really the latter that is known to us. It is the poverty of our language, or rather it is t
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POTENTIAL ENERGY
POTENTIAL ENERGY
Therefore, if energy disappears or appears, we do not say that it is destroyed or is created: we invent potential energies, into which we suppose that the energies in question have become transformed, in order that we may still think of them as being subject to an a priori principle of conservation. Although a particle of radium continually generates heat, we do not therefore think of the first principle of energetics as being invalidated, for we suppose that the energy which thus appears was re
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ISOTHERMAL AND ADIABATIC CHANGES
ISOTHERMAL AND ADIABATIC CHANGES
Let us consider the changes which occur in a gas under the influence of changes in temperature and pressure, premising that the remarks which we have to make can be applied to bodies in the liquid and solid conditions, with some necessary modifications. A gas, then, consists of a very great number of particles, or molecules, in motion. These molecules move in straight lines at very high velocities, and if the envelope in which the gas is contained is a restricted one, the molecules collide with
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THE CARNOT ENGINE
THE CARNOT ENGINE
This is an imaginary mechanism which performs a certain cycle of operations. It does not really exist, but the conception of its operation is of the greatest value in the consideration of energy-transformations, and it is for this reason that we discuss it here. Consider a gas, or some other substance capable of expanding or contracting. It contains intrinsic energy, and it is capable of doing work. Thus, since a gas can expand indefinitely it can be made to do mechanical work. A mass of gas at
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THE CARNOT POSITIVE CYCLE
THE CARNOT POSITIVE CYCLE
We have therefore a substance which can be heated by contact with a hot body, and which can then expand, doing mechanical work by raising a piston, and perhaps turning a flywheel, and on which work is then done so that it returns to its original condition. This is a cycle of operations. If we consider only the changes which occur in the working substance we can represent these changes by a diagram. First operation , (1→2). We suppose that the valve is turned so that the non-conducting plug close
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THE CARNOT NEGATIVE CYCLE
THE CARNOT NEGATIVE CYCLE
This is simply the positive cycle reversed . The reader should puzzle it out for himself if he is not already familiar with it. It consists of an adiabatic contraction 2→1, an isothermal contraction 1→4, an adiabatic expansion 4→3, and an isothermal expansion 3→2. A quantity of heat, Q 1 , is taken from the refrigerator at a temperature T 1 °, and another quantity, Q 2 , is given up to the source at a temperature T 2 °. But Q 2 is greater than Q 1 , and the engine therefore gives up more heat th
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REVERSIBILITY
REVERSIBILITY
The Carnot engine and cycle are therefore perfectly reversible. Not only can the engine turn heat into work, but it can turn work into heat. This perfect, quantitative reversibility is, however, a property of the imaginary mechanism only, and it does not exist in any actual engine....
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ENTROPY
ENTROPY
Let us consider the cycle more closely. In the operation 4→1, which is an isothermal expansion, there is a flow of heat-energy from the source and a transformation of energy into work. The gas in the condition represented by the point 4 had a certain pressure and a certain volume. In the condition represented by the point 1, its pressure has decreased, its volume has increased, and its temperature is the same. Its physical condition has been changed, and to bring it back into its former conditio
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AVAILABLE AND UNAVAILABLE ENERGY
AVAILABLE AND UNAVAILABLE ENERGY
Consider the Carnot engine as a perfect mechanism. It takes heat-energy from a source at a temperature T 2 °, and it gives up heat to a refrigerator at a temperature T 1 °, T 2 ° being greater than T 1 °. In the adiabatic expansion 1→2 the gas continues to expand until its temperature becomes equal to that of the refrigerator. It cannot, then, expand and do work any longer, and thus the proportion of the heat, Q 2 , received from the source, which can be converted into work, depends on the diffe
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INERT MATTER
INERT MATTER
We can see now what is indicated by Bergson’s “inert matter.” It is not matter deprived of energy —such an expression has no meaning— it is energy which is unavailable for further transformations . The matter in which we choose to say that this energy is inherent has become inert . Let us substitute for the Carnot engine the actual steam-engine of a ship, the condenser of which is cooled by the sea water which is taken in, and which is then heated and flows out again into the sea. The heat deriv
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