“In the field of observation,” legendary disease prevention pioneer Louis Pasteur famously proclaimed in 1854, “chance favors only the prepared mind.” “Knowledge comes from noticing resemblances and recurrences in the events that happen around us,” neuroscience godfather Wilfred Trotter asserted. That keen observation is what transmutes information into knowledge is indisputable — look no further than Sherlock Holmes and his exquisite mindfulness for a proof — but how, exactly, does one cultivate that critical faculty?

From The Art of Scientific Investigation (public library; public domain) by Cambridge University animal pathology professor W. I. B. Beveridge — the same fantastic 1957 compendium that explored the role of the intuition and imagination in science and how serendipity and “chance opportunism” fuel discovery — comes a timeless meditation on the art of observation, which he insists “is not passively watching but is an active mental process,” and the importance of distinguishing it from what we call intuition.

Though a number of celebrated minds favored intuition over rationality, and even Beveridge himself extolled the merits of the intuitive in science, he sides with modern-day admonitions about our tendency to mislabel other cognitive processes as “intuition” and advises:

It is important to realize that observation is much more than merely seeing something; it also involves a mental process. In all observations there are two elements : (a) the sense-perceptual element (usually visual) and (b) the mental, which, as we have seen, may be partly conscious and partly unconscious. Where the sense-perceptual element is relatively unimportant, it is often difficult to distinguish between an observation and an ordinary intuition. For example, this sort of thing is usually referred to as an observation: “I have noticed that I get hay fever whenever I go near horses.” The hay fever and the horses are perfectly obvious, it is the connection between the two that may require astuteness to notice at first, and this is a mental process not distinguishable from an intuition. Sometimes it is possible to draw a line between the noticing and the intuition, e.g. Aristotle commented that on observing that the bright side of the moon is always toward the sun, it may suddenly occur to the observer that the explanation is that the moon shines by the light of the sun.

For the practical applications of observation, Beveridge turns to French physiologist Claude Bernard’s model, pointing out the connection-making necessary for creativity:

Claude Bernard distinguished two types of observation: (a) spontaneous or passive observations which are unexpected; and (b) induced or active observations which are deliberately sought, usually on account of an hypothesis. … Effective spontaneous observation involves firstly noticing some object or event. The thing noticed will only become significant if the mind of the observer either consciously or unconsciously relates it to some relevant knowledge or past experience, or if in pondering on it subsequently he arrives at some hypothesis. In the last section attention was called to the fact that the mind is particularly sensitive to changes or differences. This is of use in scientific observation, but what is more important and more difficult is to observe (in this instance mainly a mental process) resemblances or correlations between things that on the surface appeared quite unrelated.

Echoing Jean Jacques Rousseau’s timeless words that “real wisdom is not the knowledge of everything, but the knowledge of which things in life are necessary, which are less necessary, and which are completely unnecessary to know” and Noam Chomsky’s similar assertion centuries later, Beveridge cautions:

One cannot observe everything closely, therefore one must discriminate and try to select the significant. When practicing a branch of science, the ‘trained’ observer deliberately looks for specific things which his training has taught him are significant, but in research he often has to rely on his own discrimination, guided only by his general scientific knowledge, judgment and perhaps an hypothesis which he entertains.

He cites Alan Gregg, the then-director of Medical Sciences for the Rockefeller Foundation:

Most of the knowledge and much of the genius of the research worker lie behind his selection of what is worth observing. It is a crucial choice, often determining the success or failure of months of work, often differentiating the brilliant discoverer from the … plodder.

Observation, like all virtuous habits worth acquiring, can be cultivated with deliberate practice — a skill that Beveridge argues, as E. O. Wilson advised young scientists and social scientists have corroborated, is superior to mindlessly stored knowledge:

Powers of observation can be developed by cultivating the habit of watching things with an active, enquiring mind. It is no exaggeration to say that well developed habits of observation are more important in research than large accumulations of academic learning.

Ultimately, Beveridge argues that the art of observation depends on developing the capacity for pattern-recognition, which in turn relies on a broad pool of networked knowledge that allows you to spot the piece that doesn’t fit:

In carrying out any observation you look deliberately for each characteristic you know may be there, for any unusual feature, and especially for any suggestive associations or relationships among the things you see, or between them and what you know. … Most of the relationships observed are due to chance and have no significance, but occasionally one will lead to a fruitful idea. […] Training in observation follows the same principles as training in any activity. At first one must do things consciously and laboriously, but with practice the activities gradually become automatic and unconscious and a habit is established. Effective scientific observation also requires a good background, for only by being familiar with the usual can we notice something as being unusual or unexplained.

It seems, then, that Steven Johnson was right in augmenting Pasteur’s famous words to “chance favors the connected mind.”

Despite its title, The Art of Scientific Investigation is a priceless treasure trove of insight on creativity in all domains — highly recommended. This article was illustrated with gender-gap-defying public domain images of women in science courtesy of the ever-wonderful Flickr Commons archive.