The philosophy of mind is one of the most alive research sectors in the field of philosophical studies nowadays. But there is no universal agreement on what exactly naturalism in the philosophy of mind is, and there is even less agreement on how naturalism in the philosophy of mind relates to naturalism as a general philosophical outlook. At the most general level, naturalism is often characterized by slogans such as -Everything that exists is part of the natural order-, or -The methods of natural science provide the only avenue to truth-, or -There is no place for a first philosophy prior to natural science-. Naturalistic theories of mind explicitly or tacitly accept or presuppose the following principles: Minds (as well as consciousness, spirit or subjectivity) are part of the real world. Nature is the whole real world. Therefore minds, consciousness and subjectivity are part of the nature. Nature can be known only by empirical sciences. There is no knowledge a priori (or obtained by methods that are different from the methods of empirical sciences) of any part of nature. Therefore minds, consciousness and subjectivity, as part of the nature, can be known only by means of empirical sciences."