Jouffroy says that “It is established by experience that we cannot give our attention to two different objects at the same time.”  And Holland states that “Two thoughts, however closely related to one another, cannot be presumed to exist at the same time.”  And Lewes has told us that “The nature of our organism prevents our having more than one aspect of an object at each instant presented to consciousness.” Whateley says:  “The best philosophers are agreed that the mind cannot actually attend to more than one thing at a time, but, when it appears to be doing so it is really shifting with prodigious rapidity backward and forward from one to the other.”

By giving a concentrated Voluntary Attention to an object, we not only are able to see and think about it with the greatest possible degree of clearness, but the mind has a tendency, under such circumstances, to bring into the field of consciousness all the different ideas associated in our memory with that object or subject, and to build around the object or subject a mass of associated facts and information.  And at the same time the Attention given the subject makes more vivid and clear all that we learn about the thing at the time, and, in fact, all that we may afterwards learn about it.  It seems to cut a channel, through which knowledge flows.

Attention magnifies and increases the powers of perception, and greatly aids the exercise of the perceptive faculties.  By “paying attention” to something seen or heard, one is enabled to observe the details of the thing seen or heard, and where the inattentive mind acquires say three impressions the attentive mind absorbs three times three, or perhaps three times “three times three,” or twenty-seven.  And, as we have just said, Attention brings into play the powers of association, and gives us the “loose end” of an almost infinite chain of associated facts, stored away in our memory, forming new combinations of facts which we had never grouped together before, and bring out into the field of consciousness all the many scraps of information regarding the thing to which we are giving attention.  The proof of this is within the experience of everyone.  Where is the one who does not remember sitting down to some writing, painting, reading, etc., with interest and attention, and finding, much to his surprise, what a flow of facts regarding the matter in hand was passing through his mind.  Attention seems to focus all the knowledge of a thing that you possess, and by bringing it to a point enables you to combine, associate, classify, etc., and thus create new knowledge. Gibbon tells us that after he gave a brief glance and consideration to a new subject, he suspended further work upon it, and allowed his mind (under concentrated attention) to bring forth all his associated knowledge regarding the subject, after which he renewed the task with increased power and efficiency.

The more one’s attention is fixed upon a subject under consideration, the deeper is the impression which the subject leaves upon the mind.  And the easier will it be for him to afterwards pursue the same train of thought and work.