 Since modes of distinct attributes cannot cause or explain one another, and since God is the cause of modes only insofar as he is considered to be affected by another thing under the attribute of which they are modes (IIp6, IIp9), it follows that every determination of an extended thing results from the exclusive determining operations of other extended things. In this light, Spinoza should have felt more acutely than Descartes the need for a set of collision laws of fully general application.