1. Tensions in the Account of Illusions in Happiness

In the Discourse on Happiness, Du Châtelet claims to provide her reader with ‘what age and the circumstances of their life would provide too slowly’, and to save them ‘time which they should devote to securing the pleasures that they can enjoy’ (Reference Du Châtelet, Zinsser, Bour and Zinsser2009: 349). She is providing advice on how to be happy, which she believes most people only understand late in life. While most of her advice—to be free of prejudice, to be virtuous and healthy—might seem fairly intuitive, Du Châtelet's suggestion that susceptibility to illusion is one of the necessary conditions for happiness is not. She writes,

Her advice is that, since most of our pleasures involve illusions, we should not use reason to dispel illusions that bring us happiness. Du Châtelet thinks that happiness consists in pleasure gained by having passions, which are movements of the soul that always have an affective part (an associated emotion) and an appetitive part (that is something like desire or motivation), and tastes, which are less intense and akin to preferences. So, if we are fond of, for instance, watching Game of Thrones, we will receive pleasure from satisfying this passion (or taste) while watching the show. This pleasure is increased, according to Du Châtelet, if while we are watching, we allow ourselves the illusion of believing that the stories depicted are real and ongoing. Giving ourselves over to these experiences as completely as possible allows for maximal enjoyment, which ‘is the polish’ that our illusions afford us (Du Châtelet Reference Du Châtelet, Antoine Suard and de Bourlet Vauxcelles1796: 15, my translation). However, one might think that in advocating the maintenance of illusions, she is condoning a mechanism that leads us into error and self-deception. After all, if one's happiness is increased by giving oneself over to illusion in certain situations, why not give oneself over completely to illusions? Would doing so result in an error on our part? Du Châtelet does not think illusions of happiness are errors. She writes,

Here, Du Châtelet argues that the illusions we allow ourselves in order to be happy are like optical illusions. Du Châtelet claimed she knew Newton's Opticks ‘almost by heart’, and optical illusions are discussed in several of her works (Zinsser Reference Zinsser2006: 162). In this passage, Du Châtelet maintains that optical illusions are not errors; rather, they merely allow us to experience things in a way that makes them useful for us as human beings. The limitations and misrepresentations of sight, for instance, allow us not to be overwhelmed by large objects in our visual array. Here, Du Châtelet takes a line on illusion very much like the one that Descartes takes in the Meditations on First Philosophy. In replying to the possible objection that God might be a deceiver because our senses do not give us the true nature of things, Descartes notes that our senses were created in the best way for our survival (that is, for our benefit). Even though the senses seem to deceive us occasionally, as when the man suffering from dropsy feels an overwhelming thirst, which if satisfied might kill him, the senses usually are an extremely efficient means for directing us to what is useful and what is harmful. Descartes writes,

The system by which sensations of pleasure and pain alert us to what is beneficial and what is harmful for our bodies does not always represent things as they truly are. Descartes goes on to argue, ‘there is nothing else which would have been so conducive to the continued well-being of the body’ (Reference Descartes, Cottingham, Stoothoff, Murdoch and Kenny1984: AT 88/CSM 61). Du Châtelet agrees that our senses are set up in such a way that they sometimes seemingly mislead us, but generally they serve the purpose of assuring our well-being. I return to this issue below in section 2.

Yet Du Châtelet sometimes discusses optical and other sensory illusions as if they were the source of some error. As Judith Zinsser notes, although Du Châtelet was ‘a strong believer in the value of “experience”, of observations by the senses tempered by reasoned reflection, she was also quick to point out that the senses can mislead and are an imperfect guide to discovery of “truth,” of what she considered certain knowledge’ (Reference Zinsser and Hayden2011: 140). As Zinsser also points out, Du Châtelet considers a case where our sense of touch might mislead us. Du Châtelet considers that sometimes two objects at the same temperature—wool and marble—will not make the same impression on a human who touches them. The marble will feel cooler than the wool, and thus we will judge it to be at a cooler temperature when it is not (Reference Du Châtelet, Zinsser, Bour and Zinsser2009: 95). In judging that the wool really is warmer than the marble we mistake our sensations for facts about the object itself. Zinsser also notes that Du Châtelet recognizes that our perception of objects is relative to our sense availability and thus may not give us information about the nature of the object itself. Zinsser writes,

Likewise, in the Foundations of Physics Du Châtelet claims that Descartes's principle of clear and distinct ideas went too far in allowing ‘a lively, internal sense of clarity and evidence to serve as the basis of our reasonings’ (Reference Du Châtelet, Zinsser, Bour and Zinsser2009: 125). She claims that this inner sense can lead to error and falsity since our perceptions of objects and their real natures might differ.

Finally, it is not clear that the illusions she claims are necessary for happiness are like sense illusions at all. For we cannot help but see the sun as we do. But believing that the events depicted in a play or opera are real might take some act of will on our part. In what follows, I explore this issue in greater detail below, but first I examine Du Châtelet's account of methodology and avoidance of error.

2. Inner Sense of Liberty and (Exterior) Sense Illusions

In what follows, I provide a more in-depth discussion of Du Châtelet's use of illusions in her other texts before returning to the Discourse on Happiness in order to assess her claims about illusions of happiness in light of her views on truth and error. I begin with her comparison of our inner sense of liberty as a possible illusion and exterior sense illusions.

In her essay ‘On Liberty’, Du Châtelet argues that we can know that we are free because we have an ‘inner sense’ of our own liberty. In her discussion, she considers the objection that such an inner sense might be deceptive like our exterior senses, which are prone to illusion. Her reply to the objection will help us see how Du Châtelet conceives of sensory illusions and why she does not see them as errors.

Du Châtelet notes that the ‘enemies of liberty’ object to the argument that our inner sense of liberty shows that we are in fact free. She states the objection as follows:

Here, the objector makes an analogy between our inner sense of our power to act as we will and our exterior sense of sight. The claim is that since our exterior senses are deceptive, we have no reason to trust the veracity of our inner sense. That is, our inner sense of liberty might be illusory. Du Châtelet responds by claiming that the two cases are not analogous. She writes,

Here, in addition to denying the illusory nature of our inner sense of liberty. Du Châtelet emphasizes some of the features of nondeceptive sense illusions. First, as I note above, sense illusions are the result of a combination of the laws of nature and the structure of the human perceptual system. Second, these illusions are necessary for our well-being. Finally, these illusions are correctable in that we can know that, and how, they misrepresent through reason and experiment. Because sense illusions have these characteristics, Du Châtelet believes the senses are not deceptive. The main difference between these sensory illusions and the case of our inner sense of liberty is that there is no way to correct for our inner sense of liberty if it is false. Thus, Du Châtelet says that if we are not really free, this would be due to a ‘perpetual illusion [“illusion perpétuelle”] that God would cause in us, and this way of acting in the supreme Being is unworthy of his nature’ (Reference Du Châtelet and Barber1989: 489, emphasis added). Of course, a false sense of liberty might still be due to our constitution and might be useful for us in the sense of making us feel responsibility for our actions, a sense of duty, guilt, and the like, but the belief that we were free would still be an error. So, this illusion of inner sense, were it real, would be of a different kind than optical and other illusions of exterior sense.

The three features of sense illusions listed above are necessary for any illusion to count as nondeceptive for Du Châtelet. It is easy to see that Du Châtelet does not confine harmless sense illusion to optical illusions. As I note above, in her Dissertation on the Nature and Propagation of Fire, she discusses an illusion of touch. In the passage quoted below, she clearly states that this illusion is due to our nature:

Du Châtelet notes that our perception of cold in these cases is an illusion. However, she does not claim that the illusion is deceptive. Rather, this is an example of a sense illusion that is easily correctable by the aid of scientific experiment. It may be difficult for us to understand how these illusions are conducive to our well-being. But her example might be understood as indicating that the sense illusion of warmth in the wool, which would lead to a preference for sleeping on it in the winter, could help preserve body heat.

While Du Châtelet notes that our senses do produce illusions, it is important for her to maintain that these illusions are not errors. After all, we rely on our senses for verifying claims about reality. To claim that our senses cannot be trusted at all because of these sensory illusions is a sure route to skepticism (as we might think that Descartes demonstrates in the First Meditation). Since we can understand the limitations of our exterior senses and be on guard for situations in which they may mislead us, we can correct for their vulnerabilities.

3. Illusions of the Imagination

The external senses are not the only faculties used in the pursuit of truth and action. Next, we turn to the use of imagination its associated illusions. In this section, I examine her views concerning the role of the imagination in metaphysics and physics and how we can avoid error in these endeavors.

In the Foundations of Physics, Du Châtelet discusses the role of imagination in pursuing truths about the nature of reality. She argues that the role of imagination is limited with respect to methodology in physics and metaphysics because many things cannot be represented pictorially. Thus, we must exercise extreme caution in order to avoid illusions of the imagination. This stance seems to put Du Châtelet in line with a tradition that is critical of the use of imagination in matters of truth and fact. While it is beyond the scope of this article to delve into the specifics of the long and interesting history of the deceptive nature of the imagination, a short overview of those authors with whom Du Châtelet was likely familiar is instructive. For instance, Pascal writes in Pensees that the imagination is ‘that deceptive faculty, which seems to have been expressly given us to lead us into necessary error’ and that

Pascal argues that imagination can lead us to truth, but because it more often leads to error and falsity, we can never trust it. Moreover, imagination presents things as true to us in the same manner whether the thing imagined is true or not. Du Châtelet seems to have similar worries about our ability to determine cases when the imagination is leading us into error. However, unlike, Pascal, she seems to think that there is a remedy for error. In a similar vein, Montaigne, whom Du Châtelet mentions in her Discourse on Happiness, argues that imagination is determined by custom and education, and that reason is powerless against it (Reference Montaigne and Screech1987: 109–20). Malebranche held that the imagination ‘consists only in the soul's power of forming images of objects producing changes in the fibers of that part of the brain which can be called the principle part, because it corresponds to all the parts of our body, and is the place where the soul immediately resides’ (Reference Malebranche, Lennon and Olscamp1997: 88). Malebranche goes on to provide detailed explanations of how the imagination is involved in both physical and mental errors. Leibniz also warns against ‘strange imagination’, ‘conceits of imagination’, and ‘specters of imagination’ in his correspondence with Clarke (Reference Leibniz and Ariew2000: 42–43, 45, 48). Leibniz's use of the term imagination in this correspondence is often in the context of critical remarks about our ability to understand the fundamental nature of the world through mental representations. Finally, Hume argues that the imagination is dangerous for reason and that philosophical mistakes often proceed ‘merely from an illusion of the imagination; and the question is, how far we ought to yield to these illusions’ (Reference Hume, Norton and Norton2007: 1.4.7.6; SBN 267). Most of these philosophers held that imagination usually leads to error and falsity, and only a two of those mentioned above thought that reason was capable of guiding us away from these errors—Leibniz and Du Châtelet.

Du Châtelet's attacks on the misuse of imagination in her Foundations focus on claims about extension as the essence of bodies and the ideas of absolute space and time. With respect to the essence of body, Du Châtelet's complaint seems to be that the criterion for having a clear and distinct idea of the nature of body, which is based on a certain inner sensation of clarity and distinctness, cannot determine the dispute. She writes of Descartes,

She argues that in this case, Descartes's imagination represented body as something extended and this produced a ‘lively and internal sense’, which he took to indicate the truth that the essence of body is extension. However, Du Châtelet held that Descartes's claim about extension could be proven false by the principle of sufficient reason. She argues that the cause of the existence of extension in the world must lie either in extended things themselves or in some non-extended thing. Since extended things cannot be the cause of themselves, the cause of extension must be simple nonextended beings. She notes, however, that this ‘conclusion astonishes the imagination, simple beings are not within its province, they cannot be represented by images, and only the understanding can conceive of them’ (Reference Du Châtelet, Zinsser, Bour and Zinsser2009: 165, emphasis added). She adds that these simple beings ‘disgust the imagination’, and that ‘this rebellion of the imagination against simple beings comes probably from our habit of representing our ideas with perceivable images, which cannot help us here’ (Reference Du Châtelet, Zinsser, Bour and Zinsser2009: 173, emphasis added). Du Châtelet saw the imagination as a source of possible error because the illusions it creates are deceptive. However, we can remedy this by the use of the principal of sufficient reason.

Du Châtelet also saw the idea of absolute space as a result of unreasoned imagination (For the debates about absolute space, see Belkind Reference Belkind2007; Garber Reference Garber1992; Gorham and Slowik Reference Gorham2012, Huggett and Hoefer Reference Huggett and Zalta2015; Janiak Reference Janiak2008; and Lin Reference Lin2016). Regarding Leibniz's denial of absolute space, she writes, ‘Mr. Leibniz was right to banish absolute Space from the Universe, and to regard the idea that several Philosophers believe they have, as an illusion of the imagination [“une illusion de l'imagination”]’ (Du Châtelet Reference Du Châtelet and Brading2017: 5.74). Noting the pictorial representation of extension and absolute space, she writes,

Because our imagination allows unlimited combination and abstraction, Du Châtelet argues that the use of imagination alone in physics and metaphysics is methodologically unsound. Without the use of sufficient reason, we fall into error with respect to the nature of material bodies and space, as well as with respect to time where use of imagination leads us to make ‘duration an eternal being’ (Reference Du Châtelet, Zinsser, Bour and Zinsser2009: 155–56). She is so wary of the use of imagination in these cases that she titles a section of the Foundations of Physics, ‘One Must Distrust One's Imagination and Only Yield to Evidence’ (Reference Du Châtelet, Zinsser, Bour and Zinsser2009: 126).

While Du Châtelet advises against the use of imagination in physics and metaphysics, she notes that it may be useful in geometry in cases where we consider simple lines and shapes. In addition, she praises the use of imagination with respect to developing testable hypotheses. She writes,

The imagination is useful in the development of hypotheses because we are imagining the possible causes of certain phenomena, which are to be determined as either true or false through further observation and experiment. In imagining these possibilities, we must draw upon our past experiences of similar instances or abstract from particular circumstances to find general patterns. These mental acts require the use of imagination, which involves memory, recombination, and abstraction in its operations. However, Du Châtelet claims that in order to keep hypotheses from being ‘fictions’ and natural philosophy from being ‘a heap of fables’ (Reference Du Châtelet, Zinsser, Bour and Zinsser2009: 155), we must obey the two rules of developing hypotheses:

The key here, of course, is that a good hypothesis is one that is consistent with the two great principles and is sensitive to the nature of reality as we currently understand it. This goes for hypotheses concerning the fundamental nature or essences of things as well. In matters concerning which no empirical study can be done, only first principles are available to help us avoid taking illusion for reality:

Despite Du Châtelet's apparent distrust of the imagination in discovering the fundamental nature of physical beings and metaphysical truths, where its use often leads us to illusions and error, she does think that there are appropriate uses of the imagination. In holding that the imagination is properly used in geometric reasoning and hypothesis development, she departs from the more radical evaluation of the imagination as a deceitful faculty against which reason is helpless. The use of first principles allows us to avoid these illusions. Du Châtelet's contrast of reason and imagination can be seen in her explanation in choosing Mandeville's Fable of the Bees as a translation project rather than a work of fiction. Zinsser notes that Du Châtelet tells us she favored works of reason over those ‘of imagination’ because ‘reason and morality are of every country’ (Reference Zinsser2002: 606).

4. Illusions of Happiness, Glory, and Love

Returning to illusions of happiness, I first examine the similarities between Du Châtelet's views and those of her friend Julien Offray de La Mettrie and then examine the way in which illusions of happiness are not errors.

As Zinsser notes, Du Châtelet's Discourse on Happiness was influenced by works on happiness written by Claude Helvéticus, Voltaire, Montaigne, and La Mettrie (Reference Zinsser2006). Barbara Whitehead has outlined some similarities between Du Châtelet's Discourse on Happiness and La Mettrie's ‘Anti-Seneca or the Sovereign Good’ (also published as Discours sur la Bonheur). Whitehead conjectures that the similarities could be explained by the fact that Du Châtelet and La Mettrie likely discussed some of the views that would occur later in their works (Reference Zinsser2006: 257). One of the topics that each of them discusses is illusion. Whitehead argues that La Mettrie takes a more radical stance on illusion than does Du Châtelet, as he argues that all illusory states, including dreams and hallucinations (like those caused by opium use), are perfectly good means to happiness. La Mettrie writes of the state induced by opium: ‘one would like to remain for eternity; it would be the true paradise of the soul if it were permanent’ (Reference La Mettrie and Thomson1996: 123). He also argues that curing someone of delirium or madness is often a ‘disservice’ (Reference La Mettrie and Thomson1996: 124). La Mettrie seems to embrace the more radical stance that any pleasant illusion, delusion, or dream, although completely divorced from reality, adds to our well-being. Finally, La Mettrie questions the utility of reason as a guide to reality or truth. He writes, ‘Could not a man's reason be always dreaming, for it deceives us so often, and doubts itself and its evidence in good faith’ (Reference La Mettrie and Thomson1996: 124).

Du Châtelet's stance on beneficial illusions is more nuanced than La Mettrie's view. First, it is likely that Du Châtelet would not accept either dreams or hallucinations as mere illusions. She thinks that illusions can be dispelled through reason, but the position of one in a dream or hallucination is not one where the agent always is capable of using reason. However, Du Châtelet writes in her Reference Du Châtelet1740 Institutions de physique (Foundations of Physics) that we can tell the difference between dreams and reality when we are awake because dreams violate the principle of sufficient reason. She notes that in dreams one thing instantly may change into another or move to a faraway place, but these occurrences cannot be real as there can be no cause or reason for them.

Recall that Du Châtelet thinks sense illusions are those most similar to illusions of happiness, and they are such that they are due to our physical constitution, necessary for our well-being, and are correctible by reason. Recall also that illusions of our inner sense of liberty are not correctable by reason while illusions of the imagination are not necessary for our well-being. Illusions of happiness might seem similar to optical illusions, as du Châtelet claims, but there might seem to be one difference: sense illusions appear unavoidable while illusions of happiness might require some sort of effort on our part. However, Du Châtelet argues that these illusions of happiness come to us as naturally as sense illusions do. After a discussion of the merits of illusion in viewing the opera, she writes,

Du Châtelet implies that the illusions we experience while watching spectacles are natural to us. We are pulled into these performances. If this is so, then it is natural to think that it is due to our human perceptual and mental constitution. But we might wonder why she believes we cannot give ourselves illusions. The answer is that close and critical examination dispels illusions of happiness, and so any subject that we initially approach in this critical way will not be one where we naturally have illusions. Once we see something in this way, we cannot force ourselves to see it in the less critical more ‘soft focus’ way that we might have seen it. So, for Du Châtelet illusions require a type of willingness to not examine things too closely. This allows us to view something as a pleasing whole rather than fixating on the small imperfections and limitations that will become apparent upon close scrutiny. In the same way, Du Châtelet thinks that once we have lost an illusion, it is impossible to get it back. If we focus on the cables that enable an actor to fly, we will lose the illusion that they do fly by means of their papier-mâché wings. This loss will put a distance between ourselves and the play that will only diminish our pleasure:

There is a reason that human beings love stories, shows, and performances of these types: they bring us pleasure. Du Châtelet seems to hold that we naturally seek pleasure and that we are fitted with the means of improving these pleasures through our susceptibility to illusion. Of course, this natural inclination is consistent with the fact that there are times when we are simply not in the mood or the spectacle at hand fails to immerse us. But when we are immersed in such an illusion, it is only through a conscious act of willing that we dispel the illusion by, for instance, reminding ourselves of how the opera is staged or the ways in which the feats are achieved.

But illusions of happiness are not simply confined to the theatre and the arts. Du Châtelet claims that illusions are helpful in all of our pleasures. She mentions specifically the pleasures of glory and of love. Du Châtelet notes that glory is completely based on illusion but that it produces a real pleasure for us. She writes,

The glory of which Du Châtelet speaks is the admiration and acclamation that one receives from others for achieving great things in one's life. This pursuit of glory, she tells us, makes human beings strive to achieve things that are beneficial to their society. The aim of this glory seems to be a sort of immorality in the minds of others—to be remembered well after your death. In Mandeville's Fable of the Bees, which Du Châtelet translated into French (with liberal additions), he often speaks of the love of glory as a positive motivating factor in human achievements. He writes of the ‘Reward of Glory … that it consists in a superlative Felicity which a Man, who is conscious of having perform'd a noble Action, enjoys in Self-love, whilst he is thinking on the Applause he expects of others’ (Reference Mandeville1988: 82).

Glory, however, is illusory in the sense that it depends on what particular societies value as useful or heroic. Du Châtelet notes that women are largely excluded from seeking glory because they lack access to education and are excluded from the professions seen as conducive to glory. There is only one way for women to seek glory—through study:

While glory is founded on illusion in that it there are no objective means by which it can be achieved, Du Châtelet still believes, like Mandeville, that glory is something that human beings naturally seek, something that brings them the real pleasure that results from the admiration of others. In addition, we can receive pleasure from imagining that this glory will continue after we die. In this way, the illusion of glory is much more like illusions of the imagination than it is like sense illusions. For much of the pleasure we get from glory comes from our imagining, as Mandeville also notes, the applause of others. This is why Du Châtelet recommends that we avoid seeking glory and try not to be ambitious. While the pursuit of glory may produce great pleasure and benefits to society, it is also a source of great frustration for many (including the half of the population that is largely are excluded from its pursuit). Du Châtelet recommends that we make our happiness as little dependent upon others as possible. That is, we should not place the bulk of our well-being in things that depend on the good opinion of society, as she thinks that people judge harshly and are unforgiving of our faults. This said, Du Châtelet thinks that the greatest possible pleasure that we can have is in love, and in love our pleasure is dependent almost completely on another.

In love, according to Du Châtelet, we are most dependent upon others and in greatest need of illusion. In order to maximize the pleasure of love one must give oneself over completely to the passion. In order to do so, one must believe that this love will last forever. Of course, Du Châtelet acknowledges, in reality we all know that the passion of love lessens over time. She writes that the ‘cooling of passion’ seems inevitable and there are not those ‘whose power of illusion never wanes (for where is illusion more important than in love?)’ (Reference Du Châtelet, Zinsser, Bour and Zinsser2009: 360–61). Du Châtelet also notes that sometimes the passion of love only fades on one side. When this happens, she seems to suggest, someone who is susceptible to illusion may continue to be in love and gain happiness from the illusion of being loved in return. She writes,

Of course, this brings up a final worry about illusions of happiness. If we can achieve pleasure and happiness from allowing ourselves to engage in an illusion, what is to keep us from either maintaining our illusions perpetually even though they have no basis in reality, or from maintaining illusions that are actually harmful and painful for us? Du Châtelet's answer is, of course, that it is as necessary for us to use reason to achieve our happiness. The use of reason can break illusions that threaten to become harmful delusions. Du Châtelet holds that in order to maximize our happiness, we must use our reason to determine, to the best of our understanding, our own abilities and circumstances, which passions are most appropriate for our present circumstances, which will serve us best in the long term, and what the appropriate means for obtaining them are. She tells us that with respect to love, it is hard to break the bonds of unrequited love when we are young, but as we age and learn about human nature such feats become easier. In addition, she cautions us to be careful of too quickly placing our happiness in another:

Du Châtelet claims that we have no other duty in life but to acquire pleasure and happiness. Thus, we must keep in mind the goal of happiness and not submit ourselves unreasonably to persons or passions that we know will cause us to be unhappy. Of course, she acknowledges, human beings do not have perfect control over the passions. Sometimes we give in to delusions of love. When one does, she tells us, ‘one must not pride oneself on a constancy that would be as ridiculous as it would be misplaced’ (Reference Du Châtelet, Zinsser, Bour and Zinsser2009: 364). We must regain our reason and not ‘blush’ at having faltered. Moreover, as Du Châtelet thinks that remorse is not a useful feeling, we must not cause ourselves more unhappiness by regretting our past errors.

Du Châtelet claims at the beginning of the Discourse that people think that it is hard to be happy, ‘but it would be much easier for men to be happy if reflecting and planning conduct preceded action’ (Reference Du Châtelet, Zinsser, Bour and Zinsser2009: 349). This reflection on what truly will be conducive to our happiness and the appropriate means for achieving it is the only way to dispel the illusions that can lead to error and delusion. While illusion may add a ‘polish’ to things that are suited to make us happy, it is for reason to determine what is suitable in the first place.

Du Châtelet thinks that we are capable of using our liberty in order to improve our ability to follow passion in accordance with reason. She defines liberty as follows: ‘I call liberty the power to think a thing, or to not think, to move or to not move, according to the choice of one's mind’ (Reference Du Châtelet and Barber1989: 484). According to Du Châtelet, liberty comes in degrees. God has the most liberty since he always is able to act on his will. Human beings have a lesser degree of liberty since we are not always able to do as we will. In her essay On Liberty she writes,

The mechanism that Du Châtelet adopts for accomplishing this is John Locke's doctrine of suspension (Reference Locke and Nidditch1975: II.xxi.47–57). She writes,

In making decisions about what passions and tastes we should pursue, we must determine what will most increase our happiness and the best means to achieving our goals. In this, we must make good use of our reason and reflect upon the choices we have:

Reason may determine that we have to vanquish some of our illusions in order to be happy. We may have to leave love behind and turn to other sources of pleasure. But reason will allow us the illusions that truly do increase our happiness. These illusions are the ones that come to us naturally, promote our well-being, and are ‘correctable’ (when necessary) by reasoning and evidence.