qualities seem to begin to change – such as a candle melting; this quality is called the tertiary quality. Tertiary qualities “of a body are those powers in it that, by virtue of its primary qualities, give it the power to produce observable changes in the primary qualities of other bodies”; “the power of the sun to melt wax is a tertiary quality of the sun”. They are “mere powers; qualities such as flexibility, ductility; and the power of sun to melt wax”. This goes along with “passive power: the capacity a thing has for being changed by another thing”. In any object, at the core are the primary qualities (unknowable by the human mind), the secondary quality (how primary qualities are perceived), and tertiary qualities (the power of the combined qualities to make a change to the object itself or to other objects). Robert Boyle's corpuscularian hypothesis states that "all material bodies are composites of ultimately small particles of matter" that "have the same material qualities as the larger composite bodies do". Using this basis, Locke defines his first group, primary qualities, as "the ones that a body doesn't lose, however much it alters." The materials retain their primary qualities even if they are broken down because of the unchanging nature of their atomic particles. If someone is curious about an object and they say it is solid and extended, these two descriptors are primary qualities. The second group consists of secondary qualities which are "really nothing but the powers to produce various sensations in us by their primary qualities." Locke argues that the impressions our senses perceive from the objects (i.e. taste, sounds, colors, etc.) are not natural properties of the object itself, but things they induce in us by means of the "size, shape, texture, and motion of their imperceptible parts." The bodies send insensible particles to our senses which let us perceive the object through different faculties; what we perceive is based on the object's composition. With these qualities, people can achieve the object through bringing "co-existing powers and sensible qualities to a common ground for explanation". Locke supposes that one wants to know what "binds these qualities" into an object, and argues that a "substratum" or "substance" has this effect, defining "substance" as follows: This substratum is a construct of the mind in an attempt to bind all the qualities seen together; it is only