Definition

1. Noun (countable and uncountable):
   • Lack of a common measure: "incommensurability" refers to the state or quality of being impossible to measure or compare using a shared standard or unit.
   • Mathematical concept: In mathematics, "incommensurability" describes the property of two quantities that have no common measure (i.e., their ratio is irrational).
   • Philosophical and scientific concept: In philosophy of science, "incommensurability" denotes the idea that competing theories or paradigms cannot be directly compared because they lack a common vocabulary or set of standards.

Usage Examples

• General:

  • The incommensurability of their moral frameworks made debate futile. (Their ethical systems could not be measured by the same standard, so discussion was pointless.)

• Mathematical:

  • The diagonal of a square demonstrates incommensurability with its side. (The ratio of the diagonal to the side is irrational, so they share no common unit of measurement.)

• Philosophical:

  • Thomas Kuhn argued that scientific paradigms exhibit incommensurability, meaning they cannot be objectively compared. (Kuhn claimed that different scientific worldviews lack a neutral basis for evaluation.)

Advanced Usage

• "Incommensurability of values": A concept in ethics where different moral values cannot be ranked or measured against each other.

  • The incommensurability of values complicates ethical decision-making. (Because some values are not comparable, choices require judgment beyond simple calculation.)

• "Incommensurability thesis": The philosophical claim that certain concepts or theories are fundamentally incomparable.

  • Proponents of the incommensurability thesis reject the idea of a universal standard for truth. (They argue that different systems of thought cannot be evaluated by a single measure.)

Variants and Related Words

• Incommensurable (adjective): impossible to measure or compare.

  • The two theories are incommensurable, as they use entirely different definitions of "mass". (They cannot be compared because their basic terms do not align.)

• Incommensurately (adverb): in a manner that lacks common measure.

  • The values were incommensurately expressed, making direct comparison impossible. (They were stated using incompatible units.)

Synonyms

• Incomparability: the quality of being unable to be compared.
• Irreducibility: the state of not being reducible to a common basis.
• Incompatibility: the inability to exist or work together due to fundamental differences.

Related Idioms

• "Apples and oranges": A common phrase for things that are fundamentally different and cannot be compared.

  • Comparing their achievements is like comparing apples and oranges — there is incommensurability between their fields. (The domains are so different that no fair comparison is possible.)

• "No common ground": Lack of shared basis for comparison or agreement.

  • The two sides had no common ground, highlighting the incommensurability of their positions. (Their starting points were so different that dialogue was impossible.)