In an analogy, two objects or events, A and B, are supposed to be similar. Then, it is argued that since A has property P, B must also have property P. An analogy is false when A and B are materially different such that B doesn’t possess property P. 2) An imperfect analogy may succeed in predicting property P in B, but in B the property is possessed differently or only partially. So, analogies fail either by seeing an analogy where none exists, or by overestimating the value or significance of the analogy. However, determining whether an analogy is good, false, or imperfect is as much an art as a science. Accordingly, the examples provided below are not necessarily false or imperfect analogies. We leave that judgment to you. Furthermore, even a good analogy is not a proof and at most provides probabilistic or inductive evidence.
- "'A good marriage is like a game of baseball. In baseball, if a player follows the rules, the game will be a success. Likewise, in marriage, if the players stick to the rules the partners accept, the marriage will flourish.' ... Marriage and baseball may have a few surface similarities, but marriage is much more complex than baseball. The relationship between 'the rules' and 'success' is infinitely more intricate in marriage than it is in baseball." (Rozakis, The Complete Idiot's Guide to Public Speaking, p. 96.)
- Just as a map is a guide, not a literal copy, of the terrain to which it refers, the mind's eye is like an imperfect map of the external world. Though what we see may have some resemblance to the world itself, we do not see the world itself.
- A common prolife argument draws this analogy. A hunter who sees movement in the brush is not permitted to fire at will. Rather, he is expected to positively identify his target as a deer or foul, and not another hunter or hiker. When human life is at stake, we must err on the side of caution. Likewise, even if we cannot determine with certainty that a fetus is a human person, we should err on the side of caution and never abort.
- "England, France, and Germany are the great powers of Europe. Both England and Germany have signified their willingness to sign this treaty. We are therefore certain that the great powers of Europe will become parties to this treaty provided we give them the opportunity." (Ketcham, The Theory and Practice of Argumentation and Debate, p. 257.)
- "Gentlemen, suppose that all the property you were worth was in gold and you put it in the hands of Blondin, the famous rope-walker, to carry it across the Niagara Falls on a tight rope. Would you shake the rope while he was passing over it, or keep shouting to him, 'Blondin, stoop a little more. Go a little faster.' No. I am sure you would not. You would hold your breath as well as your tongue, and keep your hand off until he was safely over. Now, the government is in the same situation. It is carrying an immense weight across a stormy ocean. Untold treasure are in its hands. It is doing the best it can. Don't badger it. Just keep still and it will get you safely over." (U. of Wisconsin, The Principles of Effective Debating, p. 31.) » Abraham Lincoln employed this argument to quell the restlessness of some who were pressing him to act more forcefully during the Civil War. The analogy here is compelling, but the poles in the comparison are of such a disparate nature, it's difficult to appraise its force, not to mention that any argument intended to silence dissent is deserving of particular scrutiny.
- "For example, we might enumerate many points of external resemblance between the Whale and the Shark, and found upon them an analogical argument to the effect that the respiration-processes in the two animals must be similar. The whale, we might say, resembles the shark not only in all the common characters of Vertebrates, but also in its submarine habitat and in being (as regards many species) one of the very largest of marine animals. Like the shark, it is fish-like in external form, its fusiform body being well fitted for cleaving the water. Anteriorly its body passes into the head without any distinct neck, and posteriorly it is furnished with a swimming-tail into which the body gradually tapers. It has no hairy covering. Like the shark, again, it has a wide mouth, and it is of predaceous habit, feeding only on living animal nutriment. Therefore we may with great probability conclude that its method of respiration is like that of the shark — i.e., that it breathes the oxygen dissolved in the water, and has no need to be supplied with atmospheric air. But this argument is unsound. The points that we ought to have observed are the characters connected with the function of respiration. The presence of gill-slits in the shark and their absence in the whale is a difference so essential to the inquiry that its observation would at once have been sufficient to make our analogy fall to the ground." (Gibson & Klein, The Problem of Logic, pp. 359-60.)
- "Other people resemble me in many important respects: we are all members of the same species, and consequently we have quite similar bodies; we also behave quite similarly. When I'm in extreme pain I scream, and so do most members of the human species when they are in situation in which I would expect them to be experiencing pain. The argument from analogy claims that the similarities in body and behaviour between my own case and those of other people are enough for me to infer that other people are genuinely conscious in the way that I am. (Warburton, Philosophy, p. 145.)
- "But suppose I had found a watch upon the ground, and it should be inquired how the watch happened to be in that place; I should hardly think of the answer which I had before given, — that, for any thing I knew, the watch might have always been there. Yet why should not this answer serve for the watch as well as for the stone? ... For this reason, and for no other, viz. that, when we come to inspect the watch, we perceive ... that its several parts are framed and put together for a purpose, e. g. that they are so formed and adjusted as to produce motion, and that motion so regulated as to point out the hour of the day. ... [E]very indication of contrivance, every manifestation of design, which existed in the watch, exists in the works of nature; with the difference, on the side of nature, of being greater and more, and that in a degree which exceeds all computation. ... Were there no example in the world ... except that of the eye, it would be alone sufficient to support the conclusion which we draw from it, as to the necessity of an intelligent Creator. (Paley, Natural Theology.) » Basically, Paley argued that just as we infer from the complexity and purposefulness of a watch that there is a watchmaker, so too can we infer from these properties in the natural world that a Creator exists. To what extent the analogy has merit is the subject of considerable philosophical debate.