Law of Similars Homeopathy Hahnemann: A Glossary of Core Terms

Similia Similibus Curentur: The Phrase and Its Literal Meaning

The Latin phrase breaks down into three components: similia (things that are like), similibus (by things that are like), and curentur (are cured). The full rendering is 'like things are cured by like things.' Hahnemann published the phrase in his first edition of the Organon of the Rational Art of Healing in 1799, and it reappeared in the 1805 second edition with expanded commentary. He did not coin the underlying idea in isolation; the concept of using a substance to treat the symptoms it produces in healthy people had earlier advocates, but Hahnemann gave it a systematic, testable procedure and a named principle.

In practical terms, the phrase commits to a specific causal claim: a substance that produces a particular set of symptoms in a healthy person holds the specific capacity to cure that same set of symptoms in a sick person. The word 'specific' is doing heavy work here. Hahnemann was not claiming that any substance matching one symptom would help; he was claiming that the entire constellation of effects produced during a proving must correspond to the entire constellation of symptoms presented by the patient. This is what separates the Law from a simple 'like goes with like' folk observation.

The phrase also carries an implicit rejection of what Hahnemann called antipathy (treating with opposites) and allopathy (treating with substances that produce symptoms unlike the disease). For Hahnemann, the Law of Similars was not one option among several; it was the only rational basis for selecting a therapeutic agent. Every other choice, in his framing, was guesswork or a violation of the disease's own internal logic.

• Similia: the substance that provokes symptoms in a healthy person
• Similibus: the matching symptom picture presented by the sick person
• Curentur: the claimed curative outcome when the match is exact
• The claim is specific, not general: the whole symptom set must align, not a single feature

The Proving: Hahnemann's Method of Recording Symptom Data

A proving is a structured experiment in which one or more healthy volunteers ingest a substance and then record every change in sensation, mood, sleep, appetite, and physical comfort over a defined period. Hahnemann conducted or directed hundreds of these experiments between the 1790s and his death in 1843. The recorded data formed the raw material of the Materia Medica, the reference texts that list which substances produce which symptoms in which order and with which peculiarities.

The key feature of a proving is that it is conducted on healthy individuals, not on patients. This is deliberate: the goal is to isolate the substance's specific effect from the background noise of a disease process. If a person takes fresh garlic and develops a burning sensation in the stomach, a headache, and irritability, those are the garlic's signature effects in a healthy body. When a sick person presents with that same triad, the Law of Similars says garlic is the indicated remedy.

Proving data are not binary. Hahnemann recorded the sequence in which symptoms appeared, their intensity, the time of day they worsened, and the patient's subjective character (for example, whether the headache felt like a tight band or a stabbing pain). This level of detail is what allows a practitioner to distinguish between two substances that both cause stomach burning but differ in the accompanying mental and physical picture.

Symptom Totality: What 'Like' Actually Means in Matching

The word 'like' in the Law of Similars does not refer to a single symptom. It refers to what Hahnemann called the totality of symptoms: the complete picture of the patient's physical, mental, and emotional state at the time of assessment. A patient with stomach burning who is also anxious, worse in the evening, and who craves cold drinks presents a different totality than a patient with stomach burning who is irritable, worse after eating warm food, and who feels better with heat applied to the abdomen. Under the Law, these two patients would receive different remedies even though the headline symptom is identical.

Hahnemann placed particular weight on mental and emotional symptoms. In his view, the mind's state during illness is a more reliable indicator of the correct remedy than any single physical complaint, because mental symptoms are harder to mask or misattribute. A feeling of despair, a specific type of fear, or an unusual craving can be the decisive detail that narrows the choice from dozens of candidate substances to one.

The concept of the similimum sits at the centre of this logic. The similimum is the remedy whose proving picture most closely matches the patient's totality. It is not the 'closest' match in a rough sense; it is the match where the practitioner can point to a specific proving entry and say, 'this person's experience is described in this exact language.' The goal is a near-verbatim correspondence between the patient's report and the recorded proving data.

The Law of the Minimum: Potentization Within the Framework

The Law of Similars operates in conjunction with what Hahnemann called the Law of the Minimum (simillimum dosis). The second law states that the curative power of a substance increases as it is diluted and succussed (vigorously shaken). Hahnemann argued that the minute dose is not merely safer but more potent: the dilution process, he claimed, releases a vital-force-like activity from the substance that is inaccessible in its crude form.

Potentization involves a serial dilution. A tincture of the substance is mixed with an equal volume of alcohol or water, succussed, and one drop is taken into a fresh vial of solvent. This is repeated. The notation (1X, 2X, or in centesimal scale 1C, 2C, etc.) tracks the number of dilution steps. At each step, Hahnemann believed the curative specificity increased while the material toxicity decreased. The process is called 'potentization' because, in his framework, the remedy is made more powerful, not less.

Critics note that at high dilutions (beyond 12C, roughly one part in ten trillion), the probability of a single molecule of the original substance remaining in any given dose approaches zero. Hahnemann's own explanation for this was that the diluted substance imprints an 'oscillatory' or dynamic quality on the solvent itself, a kind of information transfer that does not require material presence. This is the point at which the Law of Similars becomes entangled with a non-standard theory of how matter and energy interact.

The Organon's Specific Aphorisms on the Law

The Law of Similars is not stated as a single sentence in the Organon. It is distributed across multiple numbered paragraphs (aphorisms) in different editions. In the 1799 first edition, the principle appears in the opening sections where Hahnemann contrasts rational medicine with the 'heroic' and 'palliative' methods of his era. In the 1805 second edition, the statement is more explicit and carries the full Latin phrase with a German gloss.

The most frequently cited passage is from the 200th edition of the Organon (published posthumously in 1905 from Hahnemann's notes). Here, the Law is presented as the foundational axiom from which all subsequent therapeutic decisions follow. Hahnemann writes that the physician's task is to find the medicine that can produce in a healthy person the very symptoms the sick person is experiencing, and to administer it in the smallest possible dose. The language is prescriptive: the physician must select, not guess.

Later editions of the Organon also record Hahnemann's evolving refinements. He grew more insistent on single-remedy prescribing, more rigid about the time intervals between doses, and more explicit that the totality must include the patient's miasmatic tendency (a classification of chronic disease patterns he developed). These refinements did not alter the core statement but tightened the operational rules around it.

Hahnemann's Threefold Classification of Treatment Approaches

To make the Law of Similars intelligible by contrast, Hahnemann defined two alternative approaches and argued that both were irrational. Antipathy is the practice of treating a symptom with a substance that produces the opposite symptom: fever with a cooling agent, inflammation with an anti-inflammatory. Hahnemann acknowledged that antipathy could produce temporary relief but argued it never cured the underlying disease process and often suppressed symptoms into a deeper, more dangerous state.

Allopathy, in Hahnemann's usage, is the practice of treating a disease with a substance that produces symptoms entirely unlike the disease, often at a high dose. He associated this with the dominant medical practice of his time: bloodletting, purging, and the administration of strong mineral salts for conditions they did not specifically mimic. He considered allopathy not merely inferior but actively harmful, because it introduced a second, competing disease into the patient.

The table below summarises the three approaches as Hahnemann framed them. The distinction matters because it shows that the Law of Similars was not simply a preference for gentle remedies; it was a specific logical claim about the direction of the therapeutic match.