George Berkeley, answered from the texts and cited to the page.
An idea can be like nothing but an idea. The likeness principle is the simplest and the deepest of the arguments against matter. Two things can be known to be alike only if both can be compared, and comparison requires that both be objects of mind. The supposed material substance, ex hypothesi unperceivable, cannot be compared with any idea; therefore no idea can be known to resemble it; therefore no idea can be a "picture" or "representation" of it.
This holds whether the idea is of a primary quality or a secondary. Locke conceded that secondary qualities (colour, sound, taste, smell, warmth, cold) are not in matter as we sense them but are powers in matter to produce sensations of those qualities in us; he held that primary qualities (extension, figure, motion, solidity, number) are in matter as we conceive of them, by way of resemblance.123
The concession was fatal. If the likeness principle prevents secondary qualities from being in matter, it equally prevents primary qualities from being in matter: an idea can no more be like an extension in matter than like a colour in matter. Moreover primary qualities cannot be abstracted from secondary in any concrete case: extension is always coloured extension; motion is the motion of a coloured-and-resistant body.
Locke's distinction cannot be sustained. The matterist cannot retreat to it; the whole sensible world is in the mind, primary qualities and secondary together.45
HyLas. But what say you to fure intellect? May not abstracted ideas be framed by that faculty? PHILONOUs. Since I cannot frame abstract ideas at all, it is plain, I cannot frame them by the help of pure intellect, whatsoever 114 of all those—(A, B) of light and colours, hard and soft, hot and cold, with the rest of those. 1 28 size or figure, or sensible quality—(A, B) size, colour, @c.Works Vol 2 - Principles and Three Dialogues, pp. 204–205
Pray what think you of this? It is just come into my 30 head, that the ground of all our mistakes lies in your treating of each quality by itself. Now, I grant that each quality cannot singly subsist without the mind. Colour cannot without extension, neither can figure without some other sensible quality.Works Vol 2 - Principles and Three Dialogues, pp. 209–210
Are not these shocking notions, and are not they subject to as-many ridiculous inferences, as those you were obliged to renounce before in the case of sounds? 30 uytas. I frankly own, Philonous, that it is in vain to stand out any longer. Colours, sounds, tastes, in a word, all those termed secondary qualities, have certainly existence without the mind.Works Vol 2 - Principles and Three Dialogues, pp. 197–199
Or if you say it resembles some one only of our ideas, how shall we be able to distinguish the true copy from all the false ones? Hy.as. I profess, Philonous, I am at a loss. I know not what to say 10 to this. PHILONOUs. But neither is this all. Which are material objects in themselves, perceptible or imperceptible? HYLAS. Properly and immediately nothing can be perceived but ideas.Works Vol 2 - Principles and Three Dialogues, pp. 216–217
The very same. But doth this latter fact ever happen? PHILONOUs. You may at any time make the experiment, by looking with bare, and with the other through HYLAs. I know not how to maintain it, and yet I am loth to give up extension, I see so many odd consequences following upon such a concession. PHILONOUS. Odd, say you? After the concessions already made, Thope you will stick at nothing for its oddness.Works Vol 2 - Principles and Three Dialogues, pp. 200–201
One of Berkeley's most-vindicated diagnostic claims and the decisive technical move against Locke's representationalism. Hume in the Treatise I.iv.4 adopted the collapse without attribution and used it to undermine the entire framework of Lockean material substance. Kant's response was to relocate the question — phenomena are mind-correlative, things in themselves are unknowable — preserving the structure of the distinction at a deeper transcendental level rather than defending Locke directly. Reid's Common Sense response in the Inquiry into the Human Mind (1764) charged Berkeley with conflating psychology and metaphysics; the Reidian tradition remains a live alternative reading. Contemporary scientific realism (Boyd, Psillos) defends a successor distinction at the structural-causal level; whether this escapes the likeness principle is the contemporary question.