The distinction between primary and secondary qualities, most famously outlined by Galileo, and subsequently supported, inter alia, by Descartes and by Locke, has widely been considered one of the crucial factors in the development of modern idealism. In its contemporary form, the distinction identifies some of the perceived properties as mental phenomena due to their content and structural dependence on the mind. However, this account of the primary/secondary distinction is largely different from its original version developed by the above-mentioned philosophers, within whose work the mental being of the perceived qualities was demonstrated objectively, from the conceptually-derived nature of matter, and not subjectively, by referring to the mind’s participation in the cognitive process. It was only at the next stage of the early modern subjectivisation of sense perception, best exemplified by such philosophers as Arnold Geulincx and Richard Burthogge, that the creative role played by the mind in sensation and, consequently, the mind-dependency of the sensible qualities was recognised – a turn influenced by the reinterpretation of Aristotelian philosophy offered by Jacopo Zabarella and the Paduan school, as well as by anti-Aristotelianism of the kind developed in Netherlands. Furthermore, the two different approaches to the primary/ secondary distinction can be linked with two main types of post-Cartesian idealism, i.e. Berkeleian and Kantian – a claim for which illustrative evidence from British philosophy, namely from Berkeley’s and Burthogge’s respective theories, can be drawn.