In this blog post, we will examine the limitations and issues of analogical reasoning as a method of inference, even when it is based on simple similarities.
Analogical reasoning is a method of reasoning in which, given that two objects are similar in some respects, it is inferred that one object has an additional characteristic because the other object is known to have that characteristic. This method of argument has been widely used from the development of logic by ancient Greek philosophers to modern scientific research. Analogical reasoning is useful because it allows us to draw new conclusions from premises we already know, and is therefore commonly used in everyday life and science. In particular, the argument that animal experiments on mammals are valid for medical purposes and the criticism of this argument provide a good example of analogical reasoning.
Those who argue for the validity of animal experiments using analogical reasoning infer that because humans and laboratory animals are similar, the results of experiments on laboratory animals can be safely applied to humans when it comes to new drugs and toxic substances. Based on this, they argue that animal experiments provide clear and significant benefits to humans. For example, if positive results are obtained from experiments on mice during the development of a new drug, it is expected that these results will have a similar effect on humans.
The likelihood that the new information obtained is true is called the plausibility of the analogy. For plausibility to be high, there must be a high degree of similarity between the objects being compared, and this similarity must not be merely superficial, but must be relevant to the new information. For example, those who argue for the validity of animal experiments claim that the similarities between mammals, which are often used as experimental animals, and humans, such as the fact that they have similar blood circulation and breathe with lungs, are relevant to the experimental results, and therefore their analogy argument is highly plausible. On the other hand, although humans and tailed experimental animals do not share the similarity of having tails, this is considered irrelevant to the experiment and can therefore be ignored.
However, those who oppose animal experimentation criticize those who argue for its validity on two counts in relation to the analogy argument. First, although it is said that there are similarities between humans and laboratory animals as described above, these are only similarities at the functional level. Even if the functions of humans and laboratory animals are similar, there is scientific evidence that the causal mechanisms that realize those functions differ between animals. Second, while focusing on functional similarities, they do not pay attention to the functional similarity that humans and animals feel pain. Humans cannot directly feel the pain of animals, unlike their own pain, but even so, we can know that animals feel pain through analogy because their behavior, such as moaning or cowering when they are hit, is functionally similar to that of humans.
Furthermore, the debate over the validity of animal experimentation is not merely a scientific issue, but also an ethical one. Those who support animal experimentation argue that it is essential for saving human lives and curing diseases, while those who oppose it argue that it is unethical to cause unnecessary suffering to animals. As such, the debate over the validity and ethics of animal experimentation continues, further highlighting the limitations of the analogy argument.
In short, the first criticism points out that the analogy argument used to justify animal testing is not very plausible, while the second criticism raises ethical issues regarding animal testing on the grounds that animals also feel pain.
This is because it is considered unfair to think that experiments that cause pain to humans should not be conducted, but experiments that cause pain to animals are acceptable, given that both humans and animals feel pain. Ultimately, the issue of ethics also stems from the inconsistent use of the analogy argument. The analogy argument is an important tool not only in animal testing but also in various academic and practical situations.
For example, when introducing a new teaching method in education, if a school has achieved successful results, it is logical to expect similar results from other schools with similar environments and student characteristics. However, even in this case, it is necessary to give sufficient consideration to the differences in the environments and characteristics of the students at each school, and it can be dangerous to generalize the results based on simple similarities.
As such, although analogical reasoning has a wide range of applications and is useful, caution must always be exercised when applying it. It is necessary to thoroughly examine whether the similarities between the objects of comparison are superficial or have deep relevance, otherwise there is a risk of reaching the wrong conclusion. Therefore, when using analogy, sufficient examination and analysis are necessary to increase its plausibility. In order to increase the accuracy and reliability of analogy, it is essential to examine it from various perspectives and analyze it based on as much evidence as possible.
Ultimately, analogical reasoning is a powerful tool in itself, but its use requires thorough verification and caution. When used appropriately, analogical reasoning can be a great help in gaining new information and broadening our understanding. However, it is important to always keep in mind that if used incorrectly, it can lead to false conclusions and confusion.
