What is intelligence? Let us count the ways. Actually, the many definitions you’ll find below are merely the tip of the iceberg. I have listed my sources at the end of this post.

“I’ve become more aware of and impressed by how much of leadership is about emotional intelligence. The more you lead, the more you understand how much of it is about motivation – and motivation is about emotions…To lead, being smart isn’t sufficient. You have to connect with people so that they want to help you move the organization forward.”

Robert Joss, Dean of Stanford University’s Business School.

“Knowing a great deal is not the same as being smart; intelligence is not information alone but also judgment, the manner in which information is collected and used.”

Carl Sagan

“I not only use all the brains that I have, but all that I can borrow.”

Woodrow Wilson

“It’s not that I’m so smart, it’s just that I stay with problems longer”

Albert Einstein

“Continuous effort – not strength or intelligence – is the key to unlocking our potential.”

Winston Churchill

“Intelligence is the ability to adapt to change.”

Stephen Hawking

“The capacity to acquire and apply knowledge, especially toward a purposeful goal.”

dictionary.com

“We define emotional intelligence as the subset of social intelligence that involves the ability to monitor one’s own and others’ feelings and emotions, to discriminate among them and to use this information to guide one’s thinking and actions.”

Salovey & Mayer, Emotional Intelligence (1990)

“Does a president need to be smarter than his advisors? The key is how to define ‘smart.’ A president can hardly be more expert than, in sum, a collection of advisors…”

Ron Suskind, The Price of Loyalty

“Much evidence testifies that people who are emotionally adept — who know and manage their own feelings well, and who read and deal effectively with other people’s feelings — are at an advantage in any domain of life, whether romance and intimate relationships or picking up the unspoken rules that govern success in organizational politics.”

Daniel Goleman

“Intelligence is solving a problem or creating a product that is valued in society.”

Howard Gardner

“Intelligence should not be defined as what you know, but what you do when you don’t know what to do.”

Jerome Bruner

“Intelligence is a very general mental capability that, among other things, involves the ability to reason, plan, solve problems, think abstractly, comprehend complex ideas, learn quickly, and learn from experience. It is not merely book learning, a narrow academic skill, or test-taking smarts. Rather it reflects a broader and deeper capability for comprehending our surroundings – “catching on,” “making sense” of things, or “figuring out” what to do.”

Linda Gottfredson

“The ability to use memory, knowledge, experience, understanding, reasoning, imagination and judgment in order to solve problems and adapt to new situations.”

AllWords Dictionary, 2006

“. . . the ability of a system to act appropriately in an uncertain environment, where appropriate action is that which increases the probability of success, and success is the achievement of behavioral sub-goals that support the system’s ultimate goal.”

J. S. Albus

“Any system . . . that generates adaptive behaviour to meet goals in a range of environments can be said to be intelligent.”

D. Fogel

“Intelligence is the ability to use optimally limited resources – including time – to achieve goals.”

R. Kurzweil

Miscellaneous insights regarding intelligence:

“The test of a first-rate intelligence is the ability to hold two opposed ideas in the mind at the same time, and still retain the ability to function.”

F. Scott Fitzgerald (1896 – 1940), “The Crack-Up” (1936)

“I happen to feel that the degree of a person’s intelligence is directly reflected by the number of conflicting attitudes she can bring to bear on the same topic.”

Lisa Alther, Kinflicks, 1975

“The ability to focus attention on important things is a defining characteristic of intelligence.”

Robert J. Shiller, Irrational Exuberance

“A great deal of intelligence can be invested in ignorance when the need for illusion is deep.”

Saul Bellow (1915 – 2005)

“So far as I can remember, there is not one word in the Gospels in praise of intelligence.”

Bertrand Russell (1872 – 1970)

“What a distressing contrast there is between the radiant intelligence of the child and the feeble mentality of the average adult.”

Sigmund Freud

“We use intelligence to structure our environment so we can succeed with less intelligence. Our brains make the world smart so that we can be dumb in peace.”

Andy Clark

“Intelligence is what is measured by intelligence tests.”

E. Boring

“Success is the ability to go from one failure to another with no loss of enthusiasm.”

Winston Churchill

I need to acknowledge the efforts of my friend Tom Hoerr, who collected many of these definitions. I also made use of several of the definitions of intelligence found in a 2006 article, which was quite reasonably entitled “A Collection of Definitions of Intelligence,” by Shane Legg and Marcus Hutter.  Additionally, I pulled several of these definitions from the vast collection of quotes at The Quotations Page.