'There cannot be mental atrophy in any person who continues to observe, to remember what he observes, and to seek answers for his unceasing hows and whys about things.'

'Mr. Watson, come here. I want to see you.'

- Alexander Graham Bell's first words transmitted via telephone (March 10, 1876)

'Imagination is more important than knowledge. For knowledge is limited, whereas imagination embraces the entire world.'

- Albert Einstein

'It's those who lie outside ordinary experience who have the most to teach us.'

- Author Malcolm Gladwell (1963 - present)

'Adults ask questions as a child does. When you stop wondering, you might as well put your rocker on the front porch and call it a day.'

- Comedian and late night host Johnny Carson (1925–2005)

'Others have seen what is and asked why. I have seen what could be and asked why not.'

- Pablo Picasso

'Happiness depends more upon the internal frame of a persons own mind—than on the externals in the world.'

- George Washington (1732-1799)

'Be silent, if you choose; but when it is necessary, speak—and speak in such a way that people will remember it.'

- Wolfgang Amadeus Mozart (1756–1791)

'Knowledge will forever govern ignorance.'

- US President James Madison (1751-1836)

'I just enjoy the moment I'm in. For me, life is a whole experience, not just a series of isolated moments. It's like submerging yourself into a warm bath rather than sticking your toe under the faucet.'

- longtime 'Jeopardy!' host Alex Trebek

'The more clearly we can focus our attention on the wonders and realities of the universe about us, the less taste we shall have for destruction.'

- Marine biologist and environmentalist Rachel Carson (1907-1964)

'The urge to explore has propelled evolution since the first water creatures reconnoitered the land. Like all living systems, cultures cannot remain static; they evolve or decline. They explore or expire.'

- Astronaut Buzz Aldrin (1930-present)

A quote by scientist Nikola Tesla

"The scientific man does not aim at an immediate result ... His duty is to lay the foundation for those who are to come, and point the way."

'Don’t try to be young. Just open your mind. Stay interested in stuff. There are so many things I won’t live long enough to find out about, but I’m still curious about them.'

- Actress Betty White (1922-2021)

A history of "Memento Mori," from the ancients to today

The ancient Latin phrase 'memento mori' means 'remember you will die.' The counterintuitive utterance has long provided a moral and spiritual framework for individuals to evaluate their life's decisions and worldview. Though it appears morbid at first glance, the saying is meant to inspire a thirst for life. Review the various ways the idea has inspired different cultures in this article, from the Romans and Egyptians to contemporary tech leaders like Steve Jobs.

'The beautiful thing about learning is nobody can take it away from you.'

- American musician BB King (1925-2015)

'Those who dream by day are cognizant of many things which escape those who dream only by night.'

- Edgar Allan Poe (1809-1849) in "Elenora"

Wilhelm Wundt's place in the history of psychology

While ancient philosophers considered the central problems of psychology, it was Wilhelm Wundt who first called himself one. Here's a quick video overview of his contribution.

Wilhelm Wundt, the forgotten father of modern psychology

He was the first psychologist to call himself one, and he influenced a whole generation of early psychologists. Learn about the life and works of Wilhelm Wundt with this thorough entry from a philosophy encyclopedia.

Two scientists argue consciousness evolved through 'unlimited associative learning,' the ability to learn almost any new pattern during a lifetime.

Watch a USA Memory Champion answer questions about memory

Six-time USA Memory Champion, Nelson Dellis, answers popular questions about memory, from how sleep, stress, emotion, and attention influence memory to ways techniques like the memory palace, mnemonics, and the PAO system can dramatically improve recall.

Thomas Edison, eager to communicate with ghosts, tinkered with an apparatus called the 'spirit phone.'

'Every day sees humanity more victorious in the struggle with space and time.'

- Radio inventor Guglielmo Marconi

'In life, unlike chess, the game continues after checkmate.'

- Isaac Asimov

'The man who views the world at 50 the same as he did at 20 has wasted 30 years of his life.'

- Boxing champion Muhammad Ali (1942-2016)

'Her own thoughts and reflections were habitually her best companions.'

- Legendary author Jane Austen (1775 -1817)

The basics of behaviorism and its founder John B. Watson

Watson believed he could use classical conditioning to shape the behavior of infants toward positive outcomes, culminating in his famous "Little Albert" experiment. Here's a quick overview of his life and thought.

'Mental hygiene' was the 1843 term for mental health

It was coined by American psychiatrist William Sweetzer to reference the same idea as personal hygiene. Mental hygiene, in Sweetzer's view, needed to be maintained in the same way people attend to their personal cleanliness, an idea that was supplanted by better understanding of the complexities of mental health disorder causes in the decades that followed.

'Mistakes are almost always of a sacred nature. Never try to correct them. On the contrary: rationalize them, understand them thoroughly. After that, it will be possible for you to sublimate them.'

- Artist Salvador Dalí (1904-1989)

'In my experience, each failure contains the seeds of your next success—if you are willing to learn from it.'

- Microsoft cofounder Paul Allen (1953–2018)

Mathematicians often solve problems using wordless mental processes

It's a common technique among expert mathematicians, where thinkers rely on intuition, blurry perceptions and subconscious work—no writing, no formulas. The state is distinct from daydreaming, and often relies on sudden illuminations stemming from extended periods of subconscious reflection.

A quote by Alex Haley

"Either you deal with what is the reality, or you can be sure that the reality is going to deal with you."

'It's the repetition of affirmations that leads to belief. And once that belief becomes a deep conviction, things begin to happen.'

- Legendary boxer Muhammad Ali (1942–2016)

'Mutual ignorance breeds mutual distrust.'

- Businessman Andrew Carnegie (1835–1919)

Writer Christopher Hitchens on why Orwell matters

In this 2008 segment with NPR, the author of "Why Orwell Matters" discusses his admiration for the author and fields questions from callers. Hitchens notes that anyone can write about tyranny, but that Orwell's brilliance is in exploring why people "are so keen to obey."

'I love quotations because it is a joy to find thoughts one might have, beautifully expressed with much authority by someone recognized wiser than oneself.'

- Actress and singer Marlene Dietrich (1901-1992)

'When I was a boy and I would see scary things in the news, my mother would say to me, 'Look for the helpers. You will always find people who are helping.''

- Mister Rogers (1928-2003)

'Many of life's failures are people who did not realize how close they were to success when they gave up.'

- Inventor Thomas Edison (1847 - 1931)

Two 100-year-old sisters share their tips for staying mentally sharp

Shirley Hodes, 106, and her sister Ruth Sweedler, 103, don’t routinely do crossword puzzles, but both have stayed sharp as they aged. Though they live states apart, they share similar advice for maintaining mental acuity. They sum up their strategies for cognitive health with four verbs: work, connect, learn, and appreciate. Read this article to learn more about their approach to staying 100-plus years young.

Some of the 'Jeopardy!' host Alex Trebek's best quotes

"The secret to happiness, of course, is not getting what you want; it's wanting what you get."

How to build curiosity

Change and uncertainty induce stress, but reframing the unknown into an opportunity for discovery has tangible benefits. Approaching change with curiosity enhances activity in the hippocampus and promotes neuroplasticity, promoting learning and serving as a barrier against anxiety. A neuroscientist explains how embracing the unknown, trying small experiments, and other techniques build curiosity.

'Years ago, I tried to top everybody, but I don't anymore. I realized it was killing conversation. When you're always trying for a topper you aren't really listening.'

- Comedian Groucho Marx (1890-1977)

'Because of phones, we always have the ability to jump out of ourselves. But unless you learn how to be in your head, you’ll never learn how to create.'

- Songwriter and actor Lin-Manuel Miranda (1980-present)

'Mediocrity is always invisible until passion shows up and exposes it'

- Graham Cooke

Ten writers and thinkers on what growing older actually requires of us

The Marginalian's Maria Popova curates a collection arguing our culture has learned to dread aging while forgetting it is a privilege, and that the antidote is sustaining passions strong enough to keep us from turning inward. Voices include Simone de Beauvoir, Joan Didion, Pablo Casals, and Kahlil Gibran.

What is the brain up to when the mind wanders?

As you stare into the distance while washing your home's seemingly never-ending pile of dishes, the brain activates its default mode network. This collection of "task-negative" brain regions associated with memory, reward, action consideration, and prediction alight with activity when humans mentally turn inward, possibly giving rise to the brain's ability to wander and humans' ability to construct internal narratives about the world.

'The Father of Positive Psychology' gives tips on building resilience

People differ in how they respond to setbacks. Famed psychologist Martin Seligman outlines three key pillars for resilience: developing mental toughness by interpreting failures as external and temporary, recognizing and using one’s signature strengths, and cultivating strong relationships that offer support and meaning.

Martha Graham's philosophy of creativity

The influential choreographer and dancer once said that creative people will never be satisfied with their work. Instead, "there is only a queer divine dissatisfaction, a blessed unrest that keeps us marching and makes us more alive than the others."

'(Kids) don't remember what you try to teach them. They remember what you are.'

- "Muppets" creator Jim Henson (1936-1990)

'In three words I can sum up everything I've learned about life: it goes on.'

-Poet Robert Frost (1874-1963)

'There are no passengers on Spaceship Earth. We are all crew.'

- Philosopher Marshall McLuhan (1911-1980)