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exertions, of which few men are capable. The obvious effects which this tendency to combination produces on the judgment, in confounding together those ideas which it is the province of the metaphysician to distinguish, sufficiently illustrate the mode of its operation in those numerous instances, in which its influence, though not so complete and striking, is equally real, and far more dangerous. II. The association of ideas is a source of speculative errour, by misleading us in those anticipations of the future from the past, which are the foundation of our conduct in life. The great object of philosophy, as I have already remarked more than once, is to ascertain the laws which regulate the succession of events, both in the physical and moral worlds, in order that, when called upon to act in any particular combination of circumstances, we may be enabled to anticipate the probable course of nature from our past experience, and to regulate our conduct accordingly. As a knowledge of the established connections among events is the foundation of sagacity and of skill, both in the practical arts, and in the conduct of life, nature has not only given to all men a strong disposition to remark, with attention and curiosity, those phenomena which have been observed to happen nearly at the same time, but has beautifully adapted to the uniformity of her own operations, the laws of association in the human mind. By rendering contiguity in time one of the strongest of our associating principles, she has conjoined together in our thoughts, the same events which we have found conjoined in our experience, and has thus accommodated (without any effort on our part) the order of our ideas to that scene in which we are destined to act. The degree of experience which is necessary for the preservation of our animal existence, is acquired by all men without any particular efforts of study. The laws of nature, which it is most material for us to know, are exposed to the immediate observation of our senses, and establish, by means of the principle of association, a corresponding order in our thoughts, long before the dawn of reason and reflection; or at least long before that period of childhood, to which our recollection afterwards extends. This tendency of the mind to associate together events which have been presented to it nearly at the same time, although, on the whole, it is attended with infinite advantages, yet, like many other principles of our nature, may occasionally be a source of inconvenience, unless we avail ourselves of our reason and of our experience in keeping it under proper regulation. Among the various phenomena which are continually passing before us, there is a great proportion, whose vicinity in time does not indicate a constancy of conjunction; and unless we be careful to make the distinction between these two classes of connections, the order of our ideas will be apt to correspond with the one as well as with the other, and our unenlightened experience of the past, will fill the mind, in numberless instances, with vain expectations, or with groundless alarms, concerning the future. This disposition to confound together accidental and permanent connections, is one great source of popular superstitions. Hence the regard which is paid to unlucky days, to unlucky colours, and to the influence of the planets; apprehensions which render human life, to many, a continued series of absurd terrours. Lucretius compares them to those which children feel, from an idea of the existence
of spirits in the dark:
“Ac veluti pueri trepidant, atque omnia caecis
“In tenebris metuunt, sic nos in luce timemus,
“Interdum nihilo qua, sunt metuenda magis.” voi, i. 38
Such spectres can be dispelled by the light of philosophy only; which, by accustoming us to trace established connections, teaches us to despise those which are casual; and, by giving a proper direction to that bias of the mind which is the foundation of superstition, prevents it from leading us astray.
In the instances which we have now been considering, events come to be combined together in the mind, merely from the accidental circumstance of their contiguity in time, at the moment when we perceived them. Such combinations are confined, in a great measure, to uncultivated and unenlightened minds, or to those individuals who, from nature or education, have a more than ordinary facility of association. But there are other accidental combinations, which are apt to lay hold of the most vigorous understandings; and from which, as they are the natural and necessary result of a limited experience, no superiority of intellect is sufficient to preserve a philosopher, in the infancy of physical science.
As the connections among physical events are discovered to us by experience alone, it is evident, that when we see a phenomenon preceded by a number of different circumstances, it is impossible for us to determine, by any reasoning a priori, which of these circumstances are to be regarded as the constant, and which as the accidental, antecedents of the effect. If, in the course of our experience, the same combination of circumstances is always exhibited to us without any alteration, and is invariably followed by the same result, we must for ever remain ignorant, whether this result be connected with the whole combination, or with one or more of the circumstances combined ; and therefore, if we are anxious, upon any occasion, to produce a similar effect, the only rule that we can follow with perfect security, is to imitate in every particular circumstance the combination which we have seen. It is only where we have an opportunity of separating such circumstances from each other; of combining them variously together; and of observing the effects which result from these different experiments, that we can ascertain with precision, the general laws of nature, and strip physical causes of their accidental and unessential concomitants. To illustrate this by an example. Let us suppose that a savage, who, in a particular instance, had found himself relieved of some bodily indisposition by a draught of cold water, is a second time afflicted with a similar disorder, and is desirous to repeat the same remedy. With the limited degree of experience which we have here supposed him to possess, it would be impossible for the acutest philosopher, in his situation, to determine, whether the cure was owing to the water which was drunk, to the cup in which it was contained, to the fountain from which it was taken, to the particular day of the month, or to the particular age of the moon. In order, therefore, to ensure the success of the remedy, he will very naturally, and very wisely, copy, as far as he can recollect, every circumstance which accompanied the first application of it. He will make use of the same cup, draw the water from the same fountain, hold his body in the same posture, and turn his face in the same direction; and thus all the accidental circumstances in which the first experiment was made, will come to be associated equally in his mind with the effect produced. The fountain from which the water was drawn, will be considered as possessed of particular virtues; and the cup from which it was drunk, will be set apart from vulgar uses, for the sake of those who may afterwards have occasion to apply the remedy. It is the enlargement of experience alone, and not any progress in the art of reasoning, which can cure the mind of these associations, and free the práctice of medicine from those superstitious observances with which we always find it encumbered among rude nations.
Many instances of this species of superstition might be produced from the works of philosophers who have flourished in more enlightened ages. In particular, many might be produced from the writings of those physical inquirers who immediately succeeded to Lord Bacon; and who, convinced by his arguments, of the folly of all reasonings a priori, concerning the laws of nature, were frequently apt to run into the opposite extreme, by recording every circumstance, even the most ludicrous, and the most obviously unessential, which attended their experiments.”
The observations which have been hitherto made, relate entirely to associations founded on casual combinations of material objects, or of physical events. The effects which these associations produce on the understanding, and which are so palpable that they cannot fail to strike the most careless observer, will prepare the reader for the remarks I am now to make, on some analogous prejudices which warp our opinions on still more important subjects.
As the established laws of the material world, which have been exhibited to our senses from our infancy, gradually accommodate to themselves the order of our thoughts, so the most arbitrary and capricious institutions and customs, by a long and constant and exclusive operation on the mind, acquire such an influence in forming the intellectual habits, that every deviation from them not only produces surprise, but is apt to excite sentiments of contempt and of ridicule. A person who has never extended his views beyond that society of which he himself is a member, is apt to consider
* The reader will scarcely believe, that the following cure for a dysentery, is copied verbatim from the works of Mr. Boyle:
“Take the thigh-bone of a hanged man, (perhaps another may serve, but this was still made use of) calcine it to whiteness, and having purged the patient with an auth- monial medicine, give him one dram of this white powder for one dose, in some good cordial, whether conserve or liquor.”