For we cannot observe any alteration to be made in, or operation upon anything, but by the observable change of its sensible ideas; nor conceive any alteration to be made, but by conceiving a change of some of its ideas.
Izan ere, ezein gauzatan ere ezin dugu aldaerarik ez eraginik hauteman, haren ideia sentigarrietan hauteman daitekeen aldaketaren bidez ez bada, ez eta aldaerarik egin denik bururatu ere, haren ideiatako batean aldaketa bururatu ezean.