This paper aims to distinguish two main types of coarse graining, and reveal the relationship between the notions of coarse graining and emergence. In physics, some forms of coarse graining seem to be indispensable to show a physical property, and the other merely changes our descriptions of the system. To clarify the notion of coarse graining, this article investigates the cases of the renormalization group method and irreversibility, both of which have been important topics in philosophy of science, and the case of the rigid body in classical mechanics, which is an elementary case including coarse graining. The case studies reveal the distinction between substantial and mere coarse-graining. This distinction clarifies the relationships between the notions of coarse graining and emergence and further provides some implications for the issues about emergence.

本文旨在区分粗粒化的两种主要类型，并揭示粗粒化概念与涌现之间的关系。在物理学中，某些形式的粗粒化似乎是显示物理特性不可或缺的，而另一种则只是改变了我们对系统的描述。为了澄清粗粒化的概念，本文研究了重整化群方法和不可逆性的情况，这两者都是科学哲学中的重要主题，以及经典力学中刚体的情况，这是一个基本情况，包括粗粒化。案例研究揭示了实质性粗粒度化和纯粹粗粒度化之间的区别。