the latter, a form of causation that Talmy termed extended causation is captured. More complexity More possibilities arise when another variable is introduced: change over time. This variable is exemplified by such expressions as A gust of wind made the pages of my book turn. In force dynamic terms, the situation can be described as the entering of an antagonist (the wind) that is stronger in force than the agonist (the pages) and changes the force tendency of the pages from a state of rest to a state of action (turning). In force dynamic diagrams, this motion (‘change over time’) of the Antagonist is represented by an arrow. The diagrams in Figure 2 to the right combine a shifting antagonist with agonists of varying force tendencies. The following sentences are examples for these patterns: a. A gust of wind made the pages of my book turn. b. The appearance of the headmaster made the pupils calm down. c. The breaking of the dam let the water flow from the storage lake. d. The abating of the wind let the sailboat slow down. In this series of scenarios, various kinds of causation are described. Furthermore, a basic relationship between the concepts of ‘causing something to happen’ and ‘letting something happen’ emerges, definable in terms of the balance between the force entities and the resultants of the interaction. Force entities do not have to be physical entities. Force dynamics is directly applicable to terms involving psychological forces like to persuade and to urge. The force dynamic aspect of the sentence Herbie did not succeed in persuading Diana to sing another song can be graphically represented as easily as the earlier example sentence The door cannot open (and, incidentally, by the same diagram). In addition, force entities do not have to be physically separate. A case in point is reflexive force dynamic constructions of the type Chet was dragging himself instead of walking. It is perfectly possible to represent this in a Force Dynamic diagram (representing Chet’s will as the Agonist keeping the body — the Antagonist — in motion). Thus, even though Chet is one person, his will and his body are conceptualized separately. Psychological basis The key elements of force dynamics are very basic to human cognition. Deane (1996:56) commented that “[f]rom a cognitive perspective, Talmy’s theory is a striking example of a psychologically plausible theory of causation. Its key elements