By asking a series of questions, I aim to discover how philosophical reasoning approaches the possibility of some qualities, such as shape and duration, being more real than other qualities, such as colour. A suitable starting point to this analysis seems to be to question what we mean by qualities.
Descartes poses two central questions in his Meditations: Do others exist? and Does the past exist? By analysing the possibilities of deception and misinterpretation, he concludes that the only foundation of which he can be certain is that by the process of doubting, he must exist to doubt (cogito, ergo sum). He then turns his doubts to the reliability of his sensory perceptions of the real world, and to do so studies a piece of wax. By watching it melt, altering thereby its shape, smell, opaqueness, temperature and consistency, Descartes finds himself still concluding that the observed article is wax, and so that there must be “more to wax than our sensory input”. This example illustrates that there are intrinsically stable properties to bodies “which are known … and which pertain … real nature” as well as mutable ones: the wax tells us that shape, odour, opacity, temperature and consistency are all mutable – that wax may remain wax whilst changing these qualities, yet retains its identity via Descartes’ memory of the thing which is changing and its constancy in space.
However, it is questionable whether Descartes violates his logical reservations about the existence of the past by assuming the wax is still wax. If the reality of the wax may be condensed down to its flexibility and extension, how does anything else not merely condense down to these same qualities? Thus, how may they be said to be qualities? If these qualities are thus so generalised, Descartes cannot confirm on their basis that the wax he observed prior to its melting is still the same wax. Herein lies the problem: that Descartes does not define exactly what he means by wax: the identity “wax” might rely just as heavily upon its mutable properties as its intrinsic ones, such that the alteration brought about returns us to a new object. If chemical tests are applied to “prove” the intrinsic material constancy of the wax, this is reliant upon perception, and Descartes has dismissed the senses as doubtful and/or deceitful.
Space and time are relative to the observer. The wax appears to stay in the same space: ergo it is the same wax. However, we know from science that the whole planet is actually in motion, so the constancy of the wax in space is only relative to the earth, so it only remains as wax relative to the earth. Descartes’ wax model assumes it justified to consider space (and similarly time) a superior quality. The difference between assumed and tested qualities is that time and space are active properties, which the observer must participate in, whilst the colour and shape of the wax are independent of Descartes’ colour and shape, and so he may observe them passively.
Having considered the identity of “qualities”, we now move on to question why we would want to define any difference between qualities. The example of Descartes has shown us that active qualities are often assumed more real because they are too difficult to entangle from the self. Similarly, on burning magnesium in air, magnesium oxide forms. In studying this process chemically, it is important to define the difference between magnesium and its oxide because of their different chemical applications. Yet under appropriate conditions, the oxide may be returned to the metal, just as melted wax, on cooling, returns to its opaque form. Since the magnesium is always magnesium, and still remains, whether bound to oxygen and appearing like soil, or as a shiny metal, the intrinsic identity may be argued to be identical. Where we define the difference between treatment of magnesium and treatment of wax depends upon how such differences affect us in the real world, and whether it is necessary to define a separation. Likewise, if one piece of copper is found to conduct electricity, it increases the probability that all pieces of copper will conduct electricity, whereas if one man in a room is a third son, this does not increase the probability that all men in a given room are third sons. Some properties may be said to be law-like, and are component to inductive reasoning. Others are accidental statements which merely reflect a distribution of properties. We may choose to define a difference between the qualities of conductivity and birth order because of the way we would test and apply them.
The grue hypothesis also illustrates how we make selections in the qualities we consider most real. If grue is a predicate for observing an object as green before time t, and blue afterwards, and bleen is its opposite, a contradiction arises within probability. If every time an object is selected it is green and grue, we would predict the next selected object to be green and grue. Yet if this next object is selected after time t, it cannot be simultaneously green and grue, for grue at this time would imply blueness. We choose the predicates blue and green over grue and bleen as those with the highest inherent consistency: the probability discussion for grue must take into account the passing of time t, making grue and bleen inferior since they “reference… a specific temporal position”. We find that if t is not a recurring time, then it must be constantly redefined to give grue meaning. If it isn’t, then as time increases, the definition of grue tends towards blue. However, were we to define green and blue in terms of grue and bleen, we would see that standard colours now have a temporal reliance, where grue and bleen are statutory: green exists as grue before time t, and bleen afterwards. Goodman deduces that there is no explainable reason why we recognise green over grue.
Accepting that we separate qualities into categories because it is useful, it becomes prudent to question how far they may be separated. Descartes’ wax example has already shown us that shape may be seen as less real than time, whereas some philosophers would consider it integral to the identity of an object to have shape, whatever this shape may be, to define its existence, whereas colour may be taken as a quality of its existence. Goodman’s grue shows us that some predicates of colour may be more real or more useful than others.
Arguably, only linguistic convention separates sets of qualities. Had Descartes never seen wax melt before, would he define molten wax as the same thing as its solid substance? If he would define them differently, then would not the qualities of shape, smell, opacity, temperature and consistency, which he has defined as less real, be equally as real as flexibility and extension? Just so, were I to claim “all swans are white” and you were to present me with a bird which in every other aspect was identical to my definition of swanness, but that it were black, whilst I might retract my former statement, I may also justifiably reject this specimen as being not a swan on the premises that it lacked whiteness. Therefore, any bases for differences between qualities is contextually dependent, and a deductive production of language and mathematics.
How far the observed behaviour of objects affects our prioritisation of different qualities depends upon which qualities we consider “effects” and which primary causes. Experience limits our expectations: observable physical characteristics are often unsuitable explanations for cause and effect, since “every effect is a distinct event from its cause”. Whilst we expect one billiard ball hitting a second will cause the second to move, this is only gleamed from experience. Were we never to have seen this sequence before, we might predict that one billiard ball impacting another would bring them both to a standstill, or cause one to change colour. By equal deduction, we might infer that a bird is a swan because it is white, but that our experience has shown us that there are many other birds which are white, but in other aspects different from the swan.
Our agreed concept of reality is based upon cause and effect sequences, which are not arbitrary because they derive from repeated experiences. From experience, we assume that nature has laws which it obeys, and thus uniformity of nature allows us to assume cause and effect relations, so giving rise to a cyclic process. From this we conclude that reality has no certain basis, and whilst causation is probably valid, Hume asserts that its identification is inaccessible. It becomes philosophically inadequate, regardless of correctness, to assert that qualities may be more or less real based upon our contextual perceptions of them.
The extent to which differences between properties may be related to their degree of reality depends upon how we define reality. Descartes proposes that the “distinct idea of the nature of a body” does not “derive any argument which necessarily proves the existence of any body”. If bodies do not exist, neither do their properties, so all qualities are equally non-real. Meanwhile, whilst he perceives that the existence of a body in a dream is a reflection of its existence, or of the existence of its qualities, in waking, a “more real” state, this does not persuade him that the world we know in waking isin fact the real world, and not another reflection. Thus, we many only derive the existence of qualities, not the existence of bodies. This implies that all qualities are equally real. If we consider that dreams are a component of the real world, then bodies which exist in dreams exist in the real world, insofar as dreams exist in the real world. Hume argues that we might separate qualities into degrees of reality only if we can determine how far the existence of a body is dependent upon those qualities, giving form and presence priority over secondary qualities such as colour. Yet if the existence of qualities is more certain than the existence of bodies, then presumably the less dependent qualities should be more real?
Perhaps a more useful question would be whether the identity of reality even matters in terms of qualitative priority. In the application of qualities to scientific purpose, we sometimes need to assume differences between categories of properties, even without any philosophical basis to do so, just as Descartes did with his wax example. If a quality is passive with respect to experimentation, its contribution to the mechanism of the change under study is neglected, and the quality may be taken as fundamental. Science is concerned with determining the limits of induction by inductive methods, and may essentially only be reduced to “ultimate springs and principles” which reflect uniformity of nature. Deciding that duration is more real than colour is relevant to science because things tend to continue existing whilst changing colour, or take a reliable time to undergo a change between shades of colour only separable to a specific degree.