One can assume that there is a cause or an agent of causation, but the syntactic structure of the anticausative makes it unnatural or impossible to refer to it directly.
are not; it depends on whether causation is defined as having to do with an animate volitional agent (does "falling" mean "being accelerated down by gravity" or "being dropped/pushed down by someone"?
Many Indo-European languages lack separate morphological markings for these two classes, and the correct class needs to be derived from context: (Lithuanian) (Russian) In English, many anticausatives are of the class of "alternating ambitransitive verbs", where the alternation between transitive and intransitive forms produces a change of the position of the patient role (the transitive form has a patientive direct object, and this becomes the patientive subject in the intransitive).
In passive voice, the agent of causation is demoted from its position as a core argument (the subject), but it can optionally be re-introduced using an adjunct (in English, commonly, a by-phrase).
In the examples above, The window was broken, The ship was sunk would clearly indicate causation, though without making it explicit.
[3] Bardi is an Australian Aboriginal language in the Nyulnyulan family which uses the root -jiidi- 'go' to denote anticausatives as part of complex predicate constructions.
In the anticausative construction, the light verb reduces the valency of the predicate and the item which is closed becomes the subject.