In this paper I analyze the most controversial thesis of Aristotelian substantialism, namely, that substances cannot be composed of other substances. I call this position the Mereological Limitation Thesis (MLT). I find MLT valid and defend it. My argument for MLT is a version of the argument from the unicity of substantial form. Every substance can have only one substantial form, thus, if some substances compose the object O, then what binds them is only a set of their accidental forms (relations) and in the result thereof O is not a substance (O is not informed by a substantial form). I argue against the relativization of the substantiality of forms to the level of composition by showing that substantial forms must be absolutely identity-independent. In the last section I specify the ontological status of parts of substances and argue that they are spatially distributed bundles of accidents of a compound substance itself.

在本文中，我分析了最有争议的亚里士多德实在论的论点，即物质不能由其他物质组成。我称这个职位为“ Mereological Limitation Thesis”（MLT）。我认为MLT是有效的，并为之辩护。我对MLT的论证是从实质形式的统一性出发的论证的一个版本。每个物质只能具有一个基本形式，因此，如果某些物质组成对象O，则束缚它们的只是它们的一组偶然形式（关系），结果O不是物质（O没有实质性形式的通知）。我通过表明实质性形式必须绝对独立于身份，反对形式的实质性相对于构成水平的相对化。在上一节中，我指定了物质各部分的本体论状态，并指出它们是复合物质本身在空间上分布的事故束。