A Treatise of Human Nature taste to be in the other), arguing that unextended perceptions must somehow exist without having a location. But the contrary problem arises for dualists: how can extended perceptions (of extended objects) possibly be conjoined to a simple substance? Indeed, Hume waggishly adds, this is basically the same problem that theologians commonly press against Spinoza's naturalistic metaphysics: thus if the theologians manage to solve the problem of extended perceptions belonging to a simple substance, then they give "that famous atheist" Spinoza a solution to the problem of extended objects as modes of a simple substance. Finally, Hume examines "causal relations", arguing
Chemistry reduction as a decrease in oxidation number. Although the concept of equilibrium is widely used across sciences, in the context of chemistry, it arises whenever a number of different states of the chemical composition are possible, as for example, in a mixture of several chemical compounds that can react with one another, or when a substance can be present in more than one kind of phase. A system of chemical substances at equilibrium, even though having an unchanging composition, is most often not static; molecules of the substances continue to react with one another thus giving rise to a dynamic