Law of similars

The law of similars or similarity principle is one of the two basic concepts of homoeopathy. According to this principle, every disease is said to be curable by substances causing similar symptoms when taken by a healthy patient. The law of similars is not only a rule of thumb in homoeopathy but is understood as a basic law of nature.

Taken serious scientifically, the principle is easily disproved. It does not take more than to come up with one disease which cannot be cured by similars. One such example is sufficient to falsify (disprove) a theory expressed so broadly. Even viewed as a mere rule of thumb, it may be expected to find a vast majority of diseases which will be cured by remedies causing similar symptoms. However, such a general proof of efficacy could not be provided. Therefore, the law of similars corresponds to magical thinking and has no relation to science.

Samuel Hahnemann, the founder of homoeopathy, referred to his successful chinchona test which had inspired the law of similars. This experiment, however, could not be replicated, and is to be seen as one of the errors of homoeopathic doctrine. The law of similars already had been discussed prior to Hahnemann, but was made popular first through homoeopathy.

See also: Doctrine of Signatures

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• Deutsch: Simile-Prinzip