Full Idea
Nature's laws ....are everywhere and always the same; so that there should be one and the same method of understanding the nature of all things whatsoever, namely through nature's universal laws and rules.
Gist of Idea
Laws of nature are universal, so everything must be understood through those laws
Source
Baruch de Spinoza (The Ethics [1675], III Pref)
Book Reference
Spinoza,Benedict de: 'Ethics, Improvement of Understanding, Letters', ed/tr. Elwes,R [Dover 1955], p.129
A Reaction
Leiter calls this Methodological Naturalism, which says that the procedures and findings of philosophy should conform to those of science. I think I'm also a Substantive Naturalist, who says 'that's all there is'.