ABSTRACT
Assertions of brute fact are naturally expressed in the more concrete type of proposition; assertions of connection between conditions and results are as naturally expressed in the more abstract types of proposition. The categorical type of proposition is the natural vehicle of the more concrete assertions of brute fact; the hypothetical proposition is the natural vehicle of the more abstract assertions of universal connections. The main feature of the hypothetical type of proposition is the assertion of a connection between an antecedent and a consequent. The difference between if and when is this: if introduces a condition of a certain event and a real condition is universal, and is best expressed in an hypothetical proposition; when introduces instances of a certain event and an assertion about instances is best expressed in the categorical form of proposition. The fact remains that people do sometimes use particular hypothetical propositions, which have to be dealt with accordingly.
