In his entry from the Encyclopédie (1751–1766), Voltaire makes a puzzling statement: we ought to understand that “on n’est pas le maître de son imagination.” As Lorraine Daston observes, Voltaire is presenting a view that is typical for the Enlightenment: imagination is twofold. There is a ‘sane’ imagination, employed in both arts and sciences, and a pathological, ‘insane’ imagination, responsible for passions, diseases, and errors. Daston claims that, for Voltaire, the insane imagination is that which takes over such that the human is no longer in control, whereas a sane imagination is that which is always governed by reason. I don’t think this is quite right though. In my view, for Voltaire, both types of imagination– the ‘sane’ and the ‘insane’–act independently, in the sense that both are out of one’s control. Such that no one is truly the master of their imagination. Moreover, Daston does not observe that Voltaire’s labelling the sane imagination as active and the insane as passive is opposed to the renaissance and early modern categorisation of imagination, in which the sane imagination was seen as passive and the insane as active. Quietly, Voltaire reverses the categories. So….what are the implications of this shift?

There is a certain early modern tradition of dealing with the imagination that is a relatively little investigated world, a world filled with stories about monsters, fascination, minds communicating at a distance, with dead victims reacting in the presence of their killers. Imagination was regarded as the faculty responsible for receiving information from the senses and then combining it in order to form images of objects. When ideas were combined in accordance with sensorial input, imagination was seen as a passive faculty, subordinated to reason. And yet– the early moderns claimed– sometimes, imagination goes astray: sometimes our imagination combines images that are not supposed to go together, and thus forms images with no bearing on reality – such as that of a unicorn or a mermaid. These are the cases in which the early moderns were talking about imagination as active. It was active because it was overcoming reason. Because they were not guided by reason, those with hyperactive, and as it were, strong imagination were easily manipulated, and easily convinced by superstition. To put it bluntly (and overly simplified, of course), for the early moderns, passive imagination was ruled by reason and (most of the time) rather helpful, whereas the active imagination was unguided by reason, and rather harmful.

So let’s return now to Voltaire and see how he turns this picture upside down. Voltaire also distinguishes between the passive and the active imagination(s): the passive imagination is the one that has the function of retaining the simple impressions of objects, and the active imagination is the one that arranges these images and combines them “in a thousand manners.” We’ll turn to each of them in order to see how Voltaire modifies the early modern account.   

The passive imagination is common to animals and humans, and its functions appear to be similar to the ones he attributes to memory. But, then, Voltaire endows the passive imagination with a rather powerful function – it can also compose images of objects (even though in his introduction he suggests that this is the role of the active imagination). And when passive imagination composes ideas, “it is not the understanding that acts, but the memory which is mistaken.” So when passive imagination combines, it does so erroneously, because it is not acting through the understanding. (Let’s assume, for simplicity, that understanding and reason are the same thing.) That is, it steals the role of the active imagination, but when it does so, it always performs wrongly. Moreover, Voltaire continues, the passive imagination is an inner sense that governs the human being, and it is the source of our passions and of our errors. It should depend on the will, but instead it is what determines the will. Fear, violent desires, the diseases of the spirit, hallucinations, obsessions and enchantments are all effects that the images created by the passive imagination have upon our will. This passive imagination is, Voltaire thinks, a common characteristic of the ignorant, and it has been an instrument used by those with strong and active imaginations in order to dominate weak imaginations. We’ll return to this point later. Let’s move on now to the active imagination.

 What the active imagination does is to join together reflection and combinations (of images) with memory. In doing so it brings closer distant objects, it separates objects, it composes and changes them. There are two parts to active imagination. The first part is not something everyone has, but it is really important because it plays a major role in the invention of arts. The main feature of this part is to order its creations. This is the imagination employed not only in paintings and poems, but also in mathematics and even in the mechanical arts. The second part of the active imagination is that by which we create the details in our mental life; with its help we make our conversations charming, we paint everything in vivid images, we create the most stunning circumstances in our stories, we form and employ picturesque expressions, metaphors and allegories. The second part of the active imagination is the tool with which we create poems, odes, tragedies. And yet, not all poetic creation is the result of the active imagination. Fairy tales, Voltaire tells us, are not produced by the active imagination, because they do not follow any order. A ‘sane’ imagination corrects its own error and builds everything according to the order (of what is not clear. Of reason? Of nature?).

There is, for Voltaire, a strong correspondence between the classification of imagination and the classification of arts: from the fairy tales that are monstrous connections, to the details of description (not useful but pleasant), to invention of arts, which requires an imagination that follows an order. This correspondence deserves its own analysis, but I won’t go into this here. Instead, I would like to go back to the active–passive dichotomy and to its implications. As I hope to have suggested in this very brief discussion, both types of imagination (the passive and the active) are in fact creative, so then why hold that one is passive (while in fact it controls reason) and the other active (while it follows the order)? This is my first question. I don’t have a definitive answer, but a possible answer might be that since it is only the creations of the active imagination that have value, Voltaire’s distinction is not descriptive but prescriptive: the passive ‘insane’ imagination should not be allowed to create anything.

 A second question regards what could be called the dominance aspect of the passive imagination. During the Renaissance and the early modern period, the ‘vulgar’ were taken to have a strong and active imagination, which governed their reason. This meant that the vulgar did not use reason very frequently, and consequently could be easily manipulated. And, as we have seen, those who manipulated them had weak and passive imaginations, governed by reason. If manipulation is what one wants, one must possess the proper knowledge to do so, and one cannot have such knowledge without the use of reason. But if one uses “proper” knowledge to manipulate, is does not seem unreasonable to say that proper knowledge can also be used for malicious purposes (if, of course, we accept that manipulation is tout court bad), and all of this raises several problems regarding the morality behind the use of ‘powerful’ imaginations.

It might seem that except for a change of labels, Voltaire’s theory is very similar to the early modern tradition. But doesn’t the way in which we label the different aspects of imagination have consequences? If we think at what Voltaire would say about manipulation, perhaps one might want to defend the view that his solution for avoiding manipulation would be not to allow the passive imagination to govern the will and reason any longer, as this allows one not to be dominated by external factors, and thus not be manipulable. Is such a world realistically possible? Can we really circumvent the very pervasive activity of the passive imagination? It seems unlikely. So, that suggests a second way in which Voltaire might have dealt with manipulation: since the active imagination is governed by reason, it is allowed to act, and ultimately perhaps even to dominate ignorant minds. After all, in a world where the orders of nature and of reason are “good”, the result can only be ethical, right?

But this faith in nature and in reason does not explain Voltaire’s strong commitment to the idea that imagination, active and passive, is an independent faculty. How much can we actually trust that the active imagination really is governed by order and reason, since it is as independent as the passive one, and we know that “on n’est pas le maître de son imagination”?