The Art of Scientific Investigation

Louis Pasteur in his laboratory, holding a jar containing the spinal cord of a rabbit infected with rabies, which he used to develop a vaccine against the disease — Science History Institute/Gregory Tobias


Undoubtedly chance has played an important role in scientific discoveries. Its importance increases when we think about how common failures and frustrations are in research. Probably most of the discoveries in biology and medicine have been unexpected or at least have had an element of chance, especially the most important and revolutionary ones. This should not surprise us if we consider that if something new is revolutionary, it could hardly be foreseen relying on prior knowledge. When some scientists talk about a discovery they have made, they say almost embarrassedly, “I found it by accident.” This phrase shows that even when you know that chance is a factor in the formation of discoveries, the magnitude of its importance is rarely appreciated and the significance of its role does not seem to have been fully understood.

or this reason, the researcher should take advantage of this knowledge of the importance of chance in discoveries and not look at it as if it were a rarity or, worse still, as something that diminishes due credit for the discovery and that, therefore, should be underestimated. Although scientists can not deliberately produce chance, they should be alert to recognizing it when it happens. He who wants to dedicate his life to the advancement of science must practice his powers of observation, so that he develops that mental attitude which consists of always being on the lookout for the unexpected and getting into the habit of examining any possibility that chance offers him. Discoveries are made by attention to all indications, however small they may be.

A good maxim for the novice researcher is “Attention to the unexpected.”

Many relate chance with luck, but it is not advisable to use the term luck in research as it can lend itself to misinterpretation. There is no objection to using it when you want to mean simply coincidence, but for many people luck is a metaphysical concept, the sort that in a mystical way influences events, and this type of concept should not ever enter in scientific thinking. The good scientist pays attention to every observation or unexpected event offered by chance and investigates carefully all those that seem most promising. In this regard Alan Gregg wrote: “One wonders if that rare ability to always be aware and take advantage of the slightest deviation from the expected behavior of nature is not the true secret of the best scientific minds, a secret that could explain why some men convert the most trivial accidents into memorable events. Behind such attention lies an extreme sensitivity.”

The history of discoveries demonstrates that chance plays an important part even in those discoveries that are attributed to it completely. For this reason, it is a misleading half-truth to refer to unexpected findings under the category of “accidental discoveries.” If chance or accidents were solely responsible for such discoveries, any researcher would have equal opportunity to realize such discoveries from the start, whether that person is a Pasteur or a Bernard.

The truth of this problem is contained in Pasteur’s famous dictum: “In the field of observation, chance favors only the prepared mind.” The role of chance consists simply in providing an opportunity, but it is the scientist who has to recognize it and take advantage of it.

Assessing the Opportunities

Given that the frequency of opportunities that involve making discoveries based on chance is very small, scientists spend most of their time at their work stations always attempting “something new,” and that is how they are exposed to encountering fortunate accidents. In addition, they require an acute power of observation to see any indication that is presented and at the same time a special ability to notice the unexpected while they are waiting for the expected. Then the scientist enters the most difficult stage of all and the one that requires what Pasteur called a “prepared mind.” This stage consists of interpreting and clarifying the possible significance of any indication. In this respect, Sir Henry Souttar has noted that it is that which is contained in the brain of the observer, accumulated over years of work, that makes triumph possible. Once the discovery has been made, the scientist has to suffer the impact of skepticism and often the resistance on the part of outsiders.

In itself, mankind shows reluctance to new ideas, since new ideas are generally revolutionary ones that refute established ideas and try to establish new patterns, more evolved than the older ones. That is why the post-discovery stage is considered one of the most difficult to work through, and this is where the scientist has to fight and sometimes, as we have seen in the past, even to lose their lives. These are the ironies of life: in enriching humanity with their ideas, they are rewarded with death.

Fortunately, today that is not the form of payment. I am not referring to material goods that may be given to the scientist, but only to affording them the highest respect, while trying always to keep an open mind to the new ideas they show us. This is how we can pay them for the innumerable advances humanity receives from them.