The founding father of neuroscience, Santiago Ramón y Cajal, addresses ways in which talented individuals keep themselves from their own greatness in a chapter tilted, "diseases of will" in his book "Advice for a Young Investigator."

Published in 1897, he was able to identify six categories that still apply to people today. Despite all the advances society has undergone over the past 120 years, it seems that humanity and its psychological tendencies still remain the same.

He labels these six 'diseases of will' as contemplators, bibliophiles and polyglots, megalomaniacs, instrument addicts, misfits, and theorists. Here is a look at his labels and what it means for the modern day person.


Cajal defines this group of people as those who love the study for the beauty of the study and never have the desire to apply what they discover to a new problem or to a solution, and are therefore ineffective of making any progress.

'Bibliophiles and polyglots'

This group consists of people who use their depth of knowledge, not for advancement of any one thing in society, but rather to enlarge their own personal vanity. Cajal describes this class,

"The symptoms of this disease include encyclopedic tendencies; the mastery of numerous languages, some totally useless; exclusive subscription to highly specialized journals; the acquisition of all the latest books to appear in the bookseller's showcases; assiduous reading of everything that is important to know, especially when it interests very few; unconquerable laziness where writing is concerned; and an aversion to the seminar and laboratory." He adds, "All of the bibliophile's fondest hopes are concentrated on projecting an image of genius infused with culture."


Megalomaniacs are described as people who are gifted with talent, motivation and vision, but are cursed with an arrogance and expectation that they will become an overnight success.

All of their efforts are executed with hope of being the next big star. Obsessed with fantasy, the minute any project or endeavor becomes real and the lust has vanished, they lose interest all together.

This group lacks modesty and humility as well as a realistic expectation for what following through on vision really looks like.

'Instrument addicts'

Cajal describes instrument addicts as those who have a "fetishistic worship of research instruments. They are as fascinated by the gleam of metal as the lark is with its own reflection in a mirror."

A modern day person may spend most of their time acquiring the next software program, app, or technological gadget and yet never use it for any meaningful purpose.


"Instead of being abnormal, misfits are simply unfortunate individuals who have had work unsuited to their natural aptitudes imposed on them by adverse circumstances." Cajal adds that the reason this is a category is because this group lacks the energy to change their course in life.

One may fall into a certain job and simply complain about their position, appearing to be hopeless, victimizing themselves of their circumstance. Yet, they will never take any action to see how they might be able to improve their circumstance.


Cajal explains, "Basically, the theorist is a lazy person masquerading as a diligent one. He unconsciously obeys the law of minimum effort because it is easier to fashion a theory than to discover a phenomenon."

The theorists takes what is suppose to be a hypothesis that requires discovery and research as a conclusion and only narrows in on data that proves their theory to be correct, missing the purpose of the entire exercise of discovery.

All six categories apply to the modern day person. Having awareness of where some of these traits might be keeping you from your greatness, is the first step to understanding yourself better on the path to your greatness.