Berkeley. Three Dialogues Between Hylas and Philonous Dialogue 1.
 
Berkeley turns to an older theory of material substance, a substratum theory. At least since Aristotle, philosophers had held that qualities of material objects depend on and exist in a substance which has those qualities. This supposed substance allegedly remains the same through change. But if one claims there are material substances, one must have reasons to support that claim. In Principles §§16-24 Berkeley develops a series of arguments to the effect that (1) one cannot form an idea of a substratum, (2) the theory of material substance plays no explanatory role, and (3) it is impossible to produce evidence for the mere possibility of such an entity.
Can one form an idea a substratum? No. At least one cannot form a positive idea of a material substratum itself - something like an image of the thing itself - a point that was granted by its most fervent supporters (see Descartes 1:210; Locke 2.23.3, p. 295). The most one can do is form "An obscure and relative Idea of Substance in general" (Locke 2.23.3, p. 296), “though you know not what it is, yet you must be supposed to know what relation it bears to accidents, and what is meant by its supporting them" (PHK §16). Berkeley argues that one cannot make good on the notion of 'support' - "It is evident support cannot here be taken in its usual or literal sense, as when we say that pillars support a building: in what sense therefore must it be taken?" (PHK §16) - so one does not even have a relative idea of material substratum. Without a clear notion of the alleged relation, one cannot single out a material substance on the basis of a relation to something perceived (PHK §17).