Berkeley wants to avoid the uncertainty in Locke’s representative realism; he wants a theory of the world and our knowledge of it that allows us to be absolutely certain that the world is as it appears.
Before presenting his own theory, Berkeley must show that Locke’s theory is false. He does this by presenting arguments against each major component of Locke’s view: the causation and resemblance theses, and the primary/secondary quality distinction.
Arguments Against the Causation Thesis
The causation thesis says that a mental state is a representation of an object only if it was caused by that object. Locke needs this thesis to distinguish between mental states that are representations and those that are not.
Epistemic Argument: The purpose of this argument is to show that Locke has no evidence for his claim that some mental states are representations of material objects. The key is in the causal connection: Locke says that representation requires a causal connection, and the veil of perception prevents us from having evidence that some mental states are caused by external objects.
According to Locke’s theory, one can observe only mental states, not material objects. (The veil of perception prevents one from directly observing external objects.)
3. According to Locke’s theory, one has no evidence that material objects cause mental states.
Metaphysical Argument: The purpose of this argument is to show that, given Locke’s view of the world (particularly his mind/body dualism), a mental state could not possibly be a representation of an external object. Because minds are non-physical (according to Locke), they cannot be involved in causal connections with material objects.
1. In order for x to cause y, x and y must come into contact with one another.
2. Material objects cannot come into contact with non-physical minds. (This depends upon Locke’s claim that the body is physical but the mind is non-physical.)
3. Material objects cannot cause representations in non-physical minds.
The resemblance thesis says that a mental state is an accurate representation of an object only if that mental state is caused in the right way. Locke needs this thesis to distinguish between accurate and inaccurate mental representations.
Epistemic Argument: The purpose of this argument is to show that Locke has no evidence for his claim that some mental states are accurate representations of material objects. To have evidence that two objects resemble one another, one must examine both of them. Locke says that some mental states resemble material objects, but the veil of perception prevents him from directly examining material objects.
1. If one is unable to compare x and y, then one has no evidence that xresembles y.
2. Locke is unable to compare mental states with external material objects.
3. Locke has no evidence that mental states resemble external material objects.
Metaphysical Argument: The purpose of this argument is to show that, given Locke’s view of the world (particularly his mind/body dualism), a mental state could not possibly resemble an external object. Berkeley assumes (incorrectly, as it turns out) that objects resemble one another only if they share properties. Locke says that minds are non-physical, so mental states have no physical properties. Physical objects have only physical properties. Thus, mental states and external objects cannot share any properties, and thus cannot resemble one another.
1. If x and y do not share any properties, then x and y do not resemble one another.
2. Mental states and material objects do not share any properties.
3. Mental states and material objects do not resemble one another.
Arguments Against the Primary/Secondary Quality Distinction
According to Locke, primary qualities are really “out there” in objects, but secondary qualities are not. Instead, secondary qualities result from the way our sensory systems (vision, hearing, etc.) respond to objects’ primary qualities. The issue of accuracy applies only to primary qualities.
Berkeley’s inseparability argument states that it is impossible for there to be a distinction between primary and secondary qualities. His test for what is impossible is this: Anything that cannot be imagined is impossible. Remember that imagination involves forming a mental picture.
Berkeley argues that one cannot imagine an object’s primary qualities separate from its secondary qualities. Any mental image of primary qualities will have to include some secondary qualities as well. Because it cannot be imagined, this distinction is impossible.
Problem with this argument: Our inability to imagine something does not show that it’s impossible. E.g., a chiliagon (1,000-sided regular polygon) is possible even though we cannot imagine one.
Berkeley interprets Locke as saying that secondary qualities are the ones that vary from person to person or situation to situation. Berkeley then argues that the properties Locke says are primary (size, shape, motion/rest) vary from person to person. Thus, all properties of objects are secondary; thus, there is no primary/secondary quality distinction.
Problem with this argument: Objects do not seem to change size or shape in the ways Berkeley describes.
Idealism: The theory that only minds and ideas exist. There are no material objects, but physical objects do exist. According to idealism, a physical object is a certain sort of cluster of ideas in the mind. We are directly aware of those objects, and we can be certain that they are as they appear.
These ideas are caused by God (not by interaction with material objects).
Although we are generally directly aware of physical objects (because objects are clusters of ideas in our minds, and we are directly aware of the contents of our own minds), there are some cases in which we are indirectly aware of objects. This occurs when we are aware of just one of the object’s qualities and must infer from this what that object is. In other words, indirect awareness involves experiencing only one component of this cluster of ideas, and infer that if we were to take certain steps (e.g., investigating further) we would experience more of those ideas.
E.g., When you hear a train (but don’t see it or experience it in any other way), you infer that if you were to look outside (etc.) you would experience more of these train sensations. This is indirect awareness of the train.
Berkeley argues that it is impossible for an object to exist unperceived. This is part of defending his idealism. If objects cannot exist without being perceived, this will fit with his idealism but not with any sort of realism (which claims that there is a mind-independent external world). Berkeley has two arguments for this:
The first argument begins by claiming that an object is nothing more than the sum of its qualities. The qualities of an object are only the sensations or experiences one has when encountering that object. All sensations and experiences are in the mind, so the object itself must be in the mind. For an object to be unperceived, there would have to be a set of ideas or experiences that are not in a mind, and this is impossible.
Problem: This argument assumes the truth of idealism instead of defending it using premises that even its opponents would accept. In other words, this is a circular argument. (Definition: An argument is circular when it assumes the truth of the conclusion it is intended to support.)
The second argument uses Berkeley’s claim that something is possible only if it can be imagined (i.e., if one can form a mental image of it). Berkeley claims that one cannot have a mental image of an unperceived object, so unperceived objects are impossible.
Berkeley says that any mental image of an object is an image of a perceived object. The image is the way the object would appear if one were there perceiving it.
Problem: Berkeley’s test of possibility (can’t imagine it not possible) is incorrect. This flaw is illustrated by the chiliagon (1,000-sided regular polygon): This is possible, but cannot be imagined.
Unintended Consequences of Berkeley’s Idealism:
Objects do not persist for very long. Every time our perception of an object is interrupted (e.g., by looking away from it), that object goes out of existence and is replaced by a duplicate when we observe it again.
Two people never observe the same object. The object you perceive is a set of ideas in your mind, and the object I perceive is a set of ideas in my mind. Berkeley thinks that because all these ideas were put in our minds by god, they all count as the same object.