I. Relation of Taste to Imagination. Taste is usually associated with imagination, which is usually understood as something midway between external senses and our rational and moral abilities. Gerard is not inclined to put much weight on this usual understanding of what taste or imagination are; while our mental operations are present to us, he thinks they are hard to pin down -- they appear and disappear swiftly and seem to blend into each other. He does think, however, that this common understanding captures something genuine. There are two basic elements of this.
The first is that taste is a kind of sensation. It is an original source of ideas that cannot be reduced to other senses or to the mere act of reflection; it makes us aware of features and qualities of objects, both internal and external, but does so in a way distinct from the way in which this is done by external senses or the mere consciousness of our own thoughts. The perceptions of taste are as simple, immediate, and regular as any other sensations, and have the same kinds of effects as any other sensations. For instance, in general, when an object of sense comes before our minds, "the mind conforms itself to its nature and appearance, feels an emotion, and is put in a frame suitable and analogous" (ET 149). Our mind adapts itself to the objects of taste, like novelty, sublimity, and beauty, in the same way that it adapts itself to the objects of the external senses.
On the other hand, taste involves imaginative association. It has layers to it that are not found in the external senses, and these are built up by the ordinary operations associated with the imagination. Many of the rules and regularities governing taste are nothing other than these associative regularities of imagination; Gerard lists resemblance, contrarieity, and vicinity, as well as custom, co-existence, causation, and order (as in design or organization). This associative structure gives a complexity to taste that is lacking to the external senses. For instance, because imaginative associations, especially when close, allow the mind to move very quickly from one idea to another, this associative character of all but the most basic kinds of taste means that taste can link radically different things as if they went naturally together, or even as if they were one thing. This gives taste some of its je ne sais quoi character -- something may be beautiful, for instance, but the full account of this beauty might require extraordinary analytic precision combined with an ability to perceive accurately how a large number of features are related to each other. The full force of its beauty might be obvious to the mind rushing along associative tracks, but it might well take philosophers an immense amount of study to unravel exactly why it has this force of beauty. Likewise, this associative character is the reason why so much of our art is concerned with metaphor and symbolism.
II. Relation of Taste to Genius. Of all the questions of how taste fits into broader human psychology, the relation of taste to genius is perhaps the most interesting. Taste observes beauties; genius makes them. Is there a relation between the two that goes beyond that connection? For instance, is (to use James Beattie's terms) taste a kind of passive genius and genius a kind of active taste, so that they are complementaries? Or might it be the case that genius is just a particular kind of taste ("talent is taste exercised," as I think James McCosh will say later)? Gerard gives two very different roles to genius and taste.
The key feature of genius is its inventiveness, which Gerard links to imaginative association: "from a confused heap of materials, collected by fancy, genius, after repeated reviews and transpositions, designs a regular and well-proportioned whole" (ET 164). When we are dealing with genius in the fine arts, we need to add to this an ability to express this imaginative construct in appropriate materials. This is why poetic genius and pictorial genius can be distinguished, however; they can have a close similarity at the imaginative level, but the results are appropriate to very different kinds of materials.
Genius builds, forms, makes. Taste, however, is needed in order to impose the proper restraints on genius:
Thus genius is the grand architect that not only chuses the materials, but disposes them into a regular structure. But it is not able to finish it by itself. It needs the assistance of taste, to guide and moderate its exertions. Though the different relations of the parts, in some measure, determine the form and position of each, we acquire much ampler assurance of its rectitude, when taste has reviewed and examined both the design and the execution. It serves as a check on mere fancy; it interposes its judgment, either approving or condemning; and rejects many things which unassisted genius would have allowed. (ET 166-167)
We might put it this way: Genius is the drafting power; taste is the revising power. They both are rooted in the imagination, but they are different expressions of the same imaginative principles. You can't have one without something of the other, because they operate on the same associative principles and are cultivated in at least some of the same ways, but at the same time a given person may have more of one than the other. Bold genius might accompany poor taste; excellent taste might go with mediocre genius. In a sense, every artist is in pursuit of the perfect blending of the two, powerful genius with a taste adequate to it, and it is something that is very difficult to achieve. At the same time, it is something well worth achieving: "Taste, united to genius, renders the effects of the latter like to diamonds, which have as great solidity as splendour" (ET 168). Nonetheless, we can have good taste even where genius is lacking, because even if we do not have the dazzling spontaneous ability to order a massive number of imaginative connections into a tightly unified whole, we may still have some narrower or weaker analogue of this ability. I think we can see what Gerard has in mind here by thinking of a common experience in reading. When reading one of the great authors, like Dante, or Shakespeare, or Austen, people regularly find that they discover more every time they go back to read -- that is one of the reasons why such authors endure. The reader may not be able to grasp all the imaginative connections in a work by Austen in a way that makes for a perfectly unified experience, a sort of sheer contemplation of the whole of (say) Emma all at once, with all its parts and their appropriateness seen together, but he or she may well be able to take in (and enjoy!) a portion of them at one time, and the richness of the experience will be linked to the ability to take in all these associations together, in something at least analogous to the way in which Austen herself arranged them.
III. Relation of Taste to Criticism. Taste is the completion of the work of the artist, artisan, or author; it is the starting-point of the critic, and in the critic it must be completed by reflective judgment. As Gerard puts it, the critic must not only feel but accurately reflect so as to be able to identify the feelings and explain them. We can, in a sense, think of criticism as the opposing complement of art, since art starts with genius and improves it by taste, whereas criticism starts with taste and improves it by genius. The particular genius required for criticism is a philosophical genius, able to take a mass of thing and "subject these materials to a regular induction, reduce them into classes, and determine the general rules which govern them" (ET 171). The great critic does not merely appreciate; he or she classifies, sets in order, identifies the underlying principles, and, more than that, with extraordinary ingenuity finds ways to go beyond the obvious in doing these things. As Gerard says (ET 174),
If taste is wanting, our conclusions must be defective, faulty, or precarious; if philosophical genius, our observations will be trifling, superficial, unconnected, and perplexed with too great particularity.
Gerard has some very harsh things to say about critics through the ages on this point, so he obviously regards the relevant philosophical genius as rare. People try to substitute mechanical systems or simplistic rules for true critical genius. Real critics, however, plumb the depths of human life, tracing back the entire aesthetic experience, just as it really is, to its fundamental roots in human nature.
IV. Relation of Taste to the Provinces of Life. Gerard suggests that taste can be looked at in a very different light. How does taste relate to major areas of human life, like nature, art, and science?
With regard to nature, which is the common subject of the other two, taste and reason are employed in conjunction. In art, taste is the ultimate judge, and reason but its minister. In science, reason is supreme, but may sometimes reap advantage from using taste as an auxiliary. (ET 176)
Reason investigates the laws of nature, but taste uncovers the beauty of nature; both of them are essential features of our experience of the world. On the side of art, every art, however humble, has its own beauties and and excellences, and these are the primary point, reason serving in an instrumental capacity to taste, which sets the practical ends. And while matters of knowledge are primarily the province of reason, it is also obvious that taste plays a role. It would be foolish to draw conclusions solely on the basis of what is elegant or beautiful and take those conclusions to be certain; but it is clear that the elegance and beauty of conclusions is relevant to knowledge, when they are in their proper place. For one thing, while reason may discover, taste motivates us to discover. People are driven to understand because of the beauties they find when they do understand. Moreover, inquirers pursue not merely truths but beautiful truths -- people are dissatisfied with explanations that are clumsy and inelegant, for instance, thinking that they must at least be incomplete, whereas the beauty of a well-supported explanation strengthens our sense that it must be true. Gerard uses Newtonian physics as an example. It was accepted as it was because it was founded on good reasoning, yes; but the full explanation of why Newtonian physics was so satisfying to the understanding has to reckon with its aesthetic side, its excellence in terms of taste. It was elegant, beautiful, simple -- and on Gerard's reflex-sense account of taste, these aren't arbitrary judgments or mere expressions of preference but real properties that can actually be perceived in the system.
In these four areas Gerard has covered briefly the relation between taste and various aspects of human life. In later editions of the Essay on Taste he goes on to discuss the important question of the standard of taste. But before we look at that, I think we will take a detour and look more closely at Gerard's account of genius, as laid out in his (much later) Essay on Genius.