John Locke makes several important distinctions pertaining to ideas in his Essay Concerning Human Understanding. Among these are the distinctions between ideas arising from sensation and from reflection, between simple and complex ideas, and between the primary and secondary (sensory) qualities which give rise to ideas. I will outline these distinctions so that it is clear that there is no conflict between the different types of distinctions that Locke makes.
All of Locke's distinctions pertain to ideas, the subject of the second book of the Essay. An idea, Locke tells us at the beginning of Book Two, is an object of thinking, an entity of mental activity (Locke, 2.1.1). He repeats later that an idea is ``whatsoever the mind perceives in itself, or is the immediate object of perception, thought, or understanding'' (Locke, 2.8.8). Making a significant break from the previous philosophical tradition, Locke rejects the notion of innate ideas. There are, says Locke, no ideas known to us at birth; instead, the mind is a ``white paper'' which gains ideas through experience (Locke, 2.1.2).
Ideas may arise from two sources: sensation and reflection. Ideas from sensation rely on the senses to convey qualities, such as colors, sounds, and tastes, of external objects to the mind (Locke, 2.1.3). Ideas from reflection are ideas that arise from the mind's understanding of its own operations and are not dependent on external objects (Locke, 2.1.4). Ideas can arise from one sense, multiple senses, reflection, or by a combination of sensation and reflection (Locke, 2.3.1).
Ideas from sensation correspond with qualities of external objects. Locke (an apparent fan of distinctions), divides qualities (somewhat arbitrarily it seems to me) into primary and secondary qualities. Primary, or original, qualities are those which are inseparable from the body, such as solidity, extension, number, and motion (Locke, 2.8.9). Secondary qualities, in contrast, are not in the objects themselves, but are powers to produce various sensations in the mind, such as the power to produce the sensation of whiteness or coldness (Locke, 2.8.10). (There are also powers, of the active and passive variety, such as the power of fire to change wax by melting and of wax to be so changed, but the consideration of powers complicates the distinction here (Locke, 2.8.23).)
There are ideas corresponding to both primary and secondary qualities; those corresponding to primary qualities are resemblances, while those produced by secondary qualities are not. For example, we may say that an object has solidity (matter), but when speaking accurately would say not that a drink is cold, but that we perceive coldness. Secondary qualities, such as coldness, are subjective and depend on an observer, whereas an object has primary qualities independent of observation (Locke, 2.8.15).
Having considered simple ideas and qualities, I turn to complex ideas, which are composed of simple ideas and are of three kinds: modes, substances, and relations (Locke, 2.12.3). Modes, further classified into simple and mixed, are modifications of an idea or multiple ideas. As examples, Locke offers beauty, triangle, gratitude, and murder (Locke, 2.12.4). Substances, further divided into those of single units and collectives, are combinations of ideas such as lead (the combination of several properties), a man (a combination of parts), and a flock (a collective group) (Locke, 2.12.6). Relations involve the comparison of multiple ideas (Locke, 2.12.7).
Of these three kinds of complex ideas, perhaps the most interesting is that of substances. Complex ideas of substances are made of ideas of primary qualities, ideas of secondary (sensible) qualities, and powers which allow the substance to be altered or changed (Locke, 2.23.9). Finally, primary and secondary qualities and powers are clearly related to complex ideas. Consider the idea of a book (a complex substance). The book has solidity, size, shape, hardness, and color. It makes a particular noise when opened or dropped. It has the passive power of changing shape when torn. All of these are qualities which can be observed, and it is the perception of these qualities which produces a mental idea of a book.
Having rather explicitly reviewed the distinctions between simple and complex ideas and primary and secondary qualities, I do not see where inconsistencies between the two would arise. Ideas are mental entities (``located'' in the mind), whereas the corresponding qualities are properties or powers of external objects. There seems to me, then, no reason for conflict between the two notions to arise. I do not believe there is any direct pairing between, say, primary qualities and simple ideas or secondary qualities and complex ideas. I do not believe that the active operation of the mind which Locke speaks of with regard to complex ideas is the same operation as that by which secondary qualities are translated to ideas. Simple ideas may correspond to primary or secondary qualities; by combining simple ideas into a complex idea, a substance may be perceived. There is no need for conflict to arise between these distinctions of ideas and qualities because they are two orthogonally different kinds of distinctions.
In this essay I will consider Descartes' argument for the existence of God (as he conceives God). I will first explain why Descartes needs the existence of God to arrive at the existence of his body and external objects. I will then explain how Descartes' ``proof'' of the existence of God fails. I will then briefly suggest that Descartes' proof of the existence of God is pivotal, and that without this proof, Descartes needs some other way to rule out deception to be certain of the existence of his body and the external world.
Descartes begins his Meditations by doubting everything he had previously accepted. First, he establishes his mental existence. Then, he turns to the existence of God, a topic to which he devotes significant energy. Only then does he consider the existence of his own body and the physical objects of an external world. The ordering suggests, as I believe is the case, that Descartes relies on God's existence to establish the existence of the outside world.
Descartes' uncertainty about the existence of physical objects stems from his lack of trust in the method by which we are made aware of physical objects. Any beliefs we have about physical objects come to us through our (easily deceived) senses. Because we can not have immediate acquaintance with physical objects, only our perceptions of these objects, there is no justification for trusting that our perceptions correspond with such objects. Descartes suggests that it may be the case that there is a powerful evil demon deceiving him, causing him to believe in the existence of external objects which are really only illusions or dreams (Descartes, 79).
For Descartes to have knowledge of external objects, he must be free from such deception. So he examines whether there is such a deceiver. (Descartes, 88). Descartes attempts to show that his conception of God as a supreme creator who is ``eternal, infinite, immutable, omniscient, [and] omnipotent'' (Descartes, 90) implies that there is no way God could be a deceiver. From this Descartes will be able to argue that as he gets ideas of physical objects from God and God is not a deceiver, these physical objects must exist. Although I am not entirely convinced by this argument, it seems clear to me that if there is a deceiving God (or other such deceiver), then Descartes' conclusion that there is no certainty about external objects is the correct one.
Descartes develops not one but two proofs for the existence of God, which he presents in Meditations 3 and 5. Unfortunately, I think both of these proofs fail. The first one, concerning the origin of the idea of God, may be outlined thus: 1. I conceive of God, a perfect being. 2. That which is more perfect cannot arise from what is less perfect (Descartes, 91). 3. I am less perfect than the God which I perceive. 4. I have an idea of God and, as I am less perfect than God, that idea could not have originated from me (Descartes, 94). 5. If it did not originate from me, perhaps it came from my cause, that is, my parents (Descartes, 95). 6. But they must have received the idea from their causes, and their causes' causes... until some ultimate uncaused cause is reached, and that uncaused cause is God (Descartes, 97). 7. Therefore, my idea of God must have come from God himself, and so God exists (Descartes, 97).
My primary objection is to the second premise: that which is more perfect cannot arise from what is less perfect. I believe there are many counterexamples to this claim. Descartes' second proof (Descartes, 106-107), based on the idea that existence is part of the essence of God, fares no better:
1. I conceive of a most perfect God. 2. Something which (physically) exists is more perfect than it would be if it did not exist. 3. Therefore, if I conceive of a perfect God, he must exist. 4. Since I do conceive of such a God, God exists. That is, Descartes argues that God once conceived must exist because it is a ``contradiction to think of God (that is, a supreme being) lacking existence (that is, lacking a perfection)'' (Descartes, 107).
I think this is an extremely clever proof, but one which fails. First, I believe it is not logically sound because the second premise is false (or unsupported). Why is existence more perfect than non-existence? This is not an issue which I think Descartes has adequately addressed to assume as a premise. Second, I think there is an invalid inference in the argument based on a (deliberate) misuse of the meaning of existence. The third item (first conclusion) of the proof states that such a God must have, among his set of properties, the property of existing. However, I do not believe that existence is a normal property or predicate in this sense. Something does not have the property of existing; it simply exists. Finally, both this and the previous proof depend on a particular conception of God, as the most perfect being conceivable, rather than as the most perfect being possible. Both arguments confuse the idea of God with God himself in such a way as to beg the question of his existence.
I conclude then, that Descartes' proofs for the existence of God fail. But is such an intermediate proof necessary to reach certainty about objects of the external world? It seems clear that we need some way to discount the possibility of deception by evil demons (or other means), but perhaps the existence of a perfect non-deceiving God is not required to rule out deception. Sketching out such an argument is an interesting question to ponder. It is beyond the scope of this paper, but the suggestion of the possibility of such an argument opens up another way for Descartes to achieve certainty about the external world, while shifting the burden of proof to his opponent who must show that no alternative proof can succeed. Although Descartes' proof of the existence of God fails, an argument for the external world may be found which does not rely on God's existence The failing of Descartes' God proof need not be an immediate cause for skepticism about the external world.
Two ideas central to the moral theory of Immanuel Kant's Groundwork of the Metaphysics of Morals are those of duty and the categorical imperative. In this essay I will explore these two strongly related ideas as I sketch Kant's theories of obligation and moral worth.
Generally speaking, duty refers to both moral obligations and the compulsion felt to meet such obligations. Duty is ``the objective necessity to act from obligation'' (Kant, 107) or ``the necessity to act out of reverence for the law'' (Kant, 68). For Kant, duties are self-imposed rational rules of action. Kant enumerates duties, such as the duty of a grocer to not overcharge, the duty to preserve one's life, the duty to help others, and the duty not to lie or make false promises (Kant, 65-67). These are all things Kant believes one ought (or ought not) to do.
Duty is an important concept for Kant because it is central to his idea of moral worth. Kant's system of ethics is deontic, rather than consequential. The moral worth of an action comes not from the outcome, but from the motive by which it is performed. For an action to have moral worth, Kant says, it must be done from the motive of duty (Kant, 65). That is, it must be performed from the sense that one is doing what one ought to do.
Note that Kant does not just say for an action to have moral worth it must be performed in accord with duty. For Kant, duty is even more important than that; morally worthy actions are performed from the motive of, not just in accord with, duty. That is, Kant does not believe there is any moral worth to be ascribed to the actions of a grocer who does not overcharge so as to maintain his customers nor to the actions of one who helps others because she enjoys doing so. For an action to have moral worth, it must be done not from personal inclination, but from unwavering duty (Kant, 66).
Imperatives also play a central role in Kant's moral theory. An imperative, Kant explains, is an ought command or a moral obligation. A categorical imperative, in contrast to a hypothetical one, represents ``an action as objectively in itself apart from its relation to a further end'' (Kant, 82). A categorical imperative is an obligation which one has a duty to fulfill in all circumstances. Kant further explains that there is only one single categorical imperative (though there are several equivalent formulations of the imperative), and that this objective, rational principle is the basis of moral action.
Kant's first formulation of the categorical imperative (the formula of universal law) is as follows: ``act only on that maxim through which you can at the same time will that it should become a universal law'' (Kant, 88). Similarly, the formula of the law of nature is to ``act as if the maxim of your action were to become through your will a universal law of nature'' (Kant, 89). Kant later introduces a second formula (the formula of the end itself), which though it seems quite different is, according to Kant, equivalent: ``act in such a way that you always treat humanity never simply as a means but always as an end'' (Kant, 96). Finally, Kant considers formulas of autonomy and the kingdom of ends: to act as though the will ``can regard itself as at the same time making universal law by means of its maxim'' (Kant, 101) and ``act on the maxims of a member who makes universal laws for a merely possible kingdom of ends'' (Kant, 106).
I will focus on the first formula, to act only on maxims one would want to have as universal laws. The difference between a maxim and a law is that a maxim is a subjective principle of action, whereas a law is an objective principle (Kant, 88). The first formula then says, to act only according to those principles which one would want to be followed by all.
All imperatives of duty, Kant believes, can be derived from this categorical imperative. Kant considers the action of making a false promise (lying) in order to borrow money and the corresponding maxim to make a promise that one has no intention of keeping in order to borrow money. When deliberating whether to perform this action, one should ask what the outcome would be if the maxim were universally adopted. As this would render the act of promising meaningless, neither this maxim nor the single instance of it can be morally accepted. Kant similarly draws the conclusions that it is wrong to commit suicide, let one's talents go to waste uncultivated, and to ignore others in need of help. These examples illustrate that a rather fully developed system of moral commands can be derived from the first formulation of the categorical imperative (Kant, 89-91).
With the ideas of categorical imperatives and maxims in mind, I return to duty and moral worth. These ideas are tied together by Kant as follows: ``An action done from duty has its moral worth, not in the purpose to be attained by it, but in the maxim in accordance with which it is decided upon'' (Kant, 67-68). Moral worth is not just tied to duty, but also to the content of one's maxims. If one acts only such that the maxims of one's actions could be (and are) universal law, then one's actions are morally worthy only if they are done in accord with the categorical imperative. Duty must follow the form of a categorical imperative, an unconditional obligation. Duty also plays a second role in that one has a duty or obligation to follow the categorical imperative and act in accord with universal law.
If this seems almost circular, it is because the notions of duty and the categorical imperative are so tightly entwined. Duty relies on categorical imperatives and moral worth relies on duty. Moral worth, then, relies on the categorical imperative and one's duty to follow categorical imperatives (oughts) and the maxims which stem from these imperatives.