conditions be fulfilled (cf Collingwood [1938] 1991, 153). Thus, in some cases ('tight causes') necessary connection is associated with the efficient cause as such; "the sun's motion, for example, necessarily gives rise to changes in terrestrial bodies" (SCG II: 29.18) and is therefore absolute necessity. In other cases ('loose causes') it is relative to both the agent and the patient; "if fire is hot, it necessarily has the power of heating, yet it need not heat, for something extrinsic may prevent it" (SCG II: 30.12). However, given both the agent and the patient, the necessity is just as absolute as in those cases in which the efficient cause itself is a sufficient cause. Aquinas therefore concluded that all inanimate things are character-ized by natural necessity: "For, as nature is, so is its action; hence, given the existence of the cause, the effect must necessarily follow" (SCG II: 35.4). Whereas man is endowed with free will, "inanimate things, plants, and brute animals" behave according to natural necessity (SCG II: 47.3), which is responsible for the uniform behavior of natural things: "... the power of every agent which acts by natural necessity is determined to one effect; that is why all natural things happen in the same way, unless there be an obstacle; while voluntary things do not" (SCG II: 23.2). By saying that "all natural things happen in the same way," Aquinas meant that things belonging to the same type act similarly in similar causal circumstanc-es. By thus relating efficient causality