 Both symmetry and monotonicity have important explanatory roles for certain linguistic phenomena. Symmetry is a feature of (most of) the quantifiers allowed in so-called existential there sentences (e.g.  There are at least five men in the garden is fine, but There are most men in the garden is not). Monotonicity is crucial for explaining the distribution of polarity items (No one will ever succeed is fine but Someone will ever succeed is not: negative polarity items such as ever require a decreasing  environment).[27]  Furthermore, monotonicity is crucially involved in natural forms of reasoning; see  section 18.