Does Berkeley credibly refute the distinction of mind-independent and mind-dependent qualities?
Berkeley’s critique of materialism presents commonly accepted notions of matter with serious trouble – this essay will analyse how Berkeley’s immaterialism levels a charge against the distinction of mind-independent and mind-dependent qualities of matter, also referred to as primary and secondary qualities (cf. Locke). First we will explicate the underlying assumptions of the distinction of qualities into mind-independent and mind-dependent. Following this we will consider Berkeley’s responses to these assumptions. It will be shown that to ignore what Berkeley has to say about sensory qualities is to leave undoubted basic premises of philosophy.
The materialist account of qualities
What Berkeley habitually refers to as the ‘materialist’ position might be defined as follows: Qualities are taken to be divided into at least 2 different types – what we will call mind-independent and mind-dependent qualities. Mind-independent qualities are qualities that exist without the mind, such as extension, number, shape and motion. Mind-dependent qualities on the other hand are only within a mind – without a perceiver they would not persist. Commonly referred to as mind-dependent are colour, odour, taste, sound, as well as heat and cold.
This view as proposed by Hobbes, Descartes and Locke is based upon several premises which are important to explicate:
(i) It is supposed that mind-independent qualities, i.e. matter, exists independently of any perceiving subject
(ii) Mind-independent qualities are thought to act upon the senses (via for example motion) so as to give the perceiving subject the Idea of mind-dependent qualities.
(iii) Mind-dependent qualities somehow inhere in mind-independent qualities, i.e. objects are understood to have a disposition causing sensations (cf. Descartes).
Berkeley’s immaterialist view
Berkeley argues against all of these premises. Against (i) he maintains that material things, mind-independent qualities are in indeed inconceivable without the mind.
[…] surely there is nothing easier than to imagine trees, for instance, in a park, or books existing in a closet, and no body by to perceive them. I answer, you may so, there is no difficulty in it: but what is all this, I beseech you, more than framing in your mind certain ideas which you call books and trees, and at the same time omitting to frame the idea of any one that may perceive them? But do not you yourself perceive or think of them all the while? This therefore is nothing to the purpose: it only shows you have the power of imagining or forming ideas in your mind; but it doth not shew that you can conceive it possible, the objects of your thought may exist without the mind: to make out this, it is necessary that you conceive them existing unconceived or unthought of, which is a manifest repugnancy. (PHK23)
Berkeley’s move is a simple one: As no objects can be imagined by a mind without the mind itself conceiving of them and thereby contemplating but the ideas of the mind itself, the conclusion that there is a material world because we can imagine a world containing material objects unperceived does not follow.
Furthermore, the proposition that there is an external material world is but an inference from the occurrence of Ideas in the Mind, which might be interpreted so as to resemble mind-independent qualities. Yet as one must do with any and all inferences, we must prove that it is indeed the best possible explanation – it is here that Berkeley’s argument acquires its full strength: he argues that to presume the existence of the material world, all the whilst being led to doubt by mistaken sensory perceptions cannot but lead to scepticism. Indeed, to have Ideas he thinks does not entail the existence of objects causing them. Instead of arguing in favour of ever disputed mind-independent qualities Berkeley advances the mind-dependency of all sensory input. (PHK19)
Premise (ii) entails that the existence of mind-independent qualities is prior to the occurrence of mind-dependent qualities. Accordingly it should be a simple task to conceive of mind-independent qualities on their own, of objects where all mind-dependent qualities have been subtracted and all that is left is left is but extension, shape and motion. Yet to think of an apple only as extension, without colour or other mind-dependent qualities is not possible – it seems that to conceive of an object consisting of purely primary qualities is unattainable. 
Premise (iii) requires us to distinguish between qualities of an object and qualities that these ‘primary’ qualities cause. However, this distinction as Berkeley renders apparent is ultimately arbitrary for all qualities can be shown to reside in the mind itself:
[…] why may we not as well argue that figure and extension are not patterns or resemblances of qualities existing in Matter, because to the same eye at different stations, or eyes of a different texture at the same station, they appear various, and cannot therefore be the images of anything settled and determinate without the mind? (PHK14)
Imagine, if you will, a tower standing in the middle of a field and a man walking towards it, when will he come to know the extension of the tower? As he walks toward it, surely his judgement about the size of the building will change continuously; even as he comes closer he cannot pass any absolute judgement about the ‘true’ extension of the construction. Can the extension of the tower be said to have remained the same throughout the experience of the man? Surely not, it seems then that Berkeley is correct to conflate mind-independent and mind-dependent qualities into one set of mind-dependent qualities.
Is it not as reasonable to say that motion is not without the mind, since if the succession of ideas in the mind become swifter, the motion, it is acknowledged, shall appear slower without any alteration in any external object? (PHK14)
Berkeley’s example concerning motion suggests an all too obvious counterargument materialists might invoke: Indubitably one might argue that motion can be determined and established as mind-independent by consulting another mind or other equipment providing empirical evidence. Thus evidence may be offered to resolve the deadlock.
This argument rests upon two premises:
(i) Firstly, subjective perception is thought to be insufficient.
(ii) Secondly, it is presupposed that an objective perception of the object (i.e. its motion) can be accomplished.
Berkeley’s response might read as follows: Premise (ii) ignores a fundamental aspect of perception itself, namely that any perception must always be mediated by a mind. To invalidate Berkeley’s argument one would appeal to appearances, however appearances as perceptions are mind-dependent. This of course seems to commit us to saying that premise (i) bears no relevance. This is due to two reasons: Firstly, as the Idea of an object is not the representation of an object, there are no grounds for comparison with a model or an original. Secondly, as the only perception available is the sensory perception of a mind there is no alternative promising objectivity.
As the Idea of an object is at no stage a representation of an object and indeed the perceptions of an object directly constitute the object as object there arises a difficulty with Berkeley’s account of sensory perception: If perceptions directly constitute their object and there is no original or model to compare it with, how can one’s perception at any point be incorrect? It is clear that in everyday routine we often encounter situations in which our perceptions are invalidated and said to be incorrect. As we have seen above mind-independent and mind-dependent qualities are one and the same in so far as they are both mind-dependent, extension, shape and motion, colour, odour and taste all are completely dependent on the perceiving mind. Consequently an object for Berkeley is always exactly like our sensory perception.
Berkeley resolves this by saying that we are not mistaken in the immediate perception, but rather in the inferences we make. Recall the man walking towards the tower – all his estimates of the size of the tower are true in the moment in which they are formulated, his error then would not be to treat his judgement as true but rather to make the inference that the size of the tower does not change as he moves toward it.
Berkeley’s arguments for the mind-dependency of all qualities have been demonstrated to refute the materialist account of sensory qualities. His account, though startling it may be, can provide responses to the different objections that have been levelled against it. Berkeley’s immaterialist view thus has to be taken seriously and the distinction of mind-independent and mind-dependent qualities should be abandoned.
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