Here are some excerpts from Rilke's observations of Rodin published in this riveting small book (made available for free use online via Project Gutenberg).

"For it was just that which Rodin was seeking: the grace of the great things."

"There were small figures, animals particularly ... All had transformed and accommodated themselves to this environment; they had lost nothing of life. On the contrary, they lived more strongly and more vehemently—lived forever the fervent and impetuous life of the time that had created them. And whosoever saw these figures felt that they were not born out of a whim nor out of a playful attempt to find forms unheard of before. Necessity had created them."

"The language of this art was the body."

"Here was a task as great as the world ... Here already Rodin's deep harmony with Nature revealed itself; that harmony which the poet George Rodenbach calls an elemental power ... He began with the seed beneath the earth, as it were. And this seed grew downward, sunk deep its roots and anchored them before it began to shoot upward in the form of a young sprout. This required time, time that lengthened into years. "One must not hurry," said Rodin to the few friends who gathered about him, in answer to their urgence."

"His real development ... was compressed into the free hours of the evening and unfolded itself in the solitary stillness of the nights; and he had to bear this division of his energy for years. He possessed the quiet perseverance of men who are necessary, the strength of those for whom a great work is waiting."

"Rodin knew that, first of all, sculpture depended upon an infallible knowledge of the human body ... it was this surface toward which his search was directed. It consisted of infinitely many movements. The play of light upon these surfaces made manifest that each of these movements was different and each significant ... There were undulations without end. There was no point at which there was not life and movement."

"Rodin had now discovered the fundamental element of his art; as it were, the germ of his world. It was the surface,—this differently great surface, variedly accentuated, accurately measured, out of which everything must rise,—which was from this moment the subject matter of his art, the thing for which he laboured, for which he suffered and for which he was awake. His art was not built upon a great idea, but upon a minute, conscientious realization, upon the attainable, upon a craft."

"The next task was to become master of himself and of his abundance. Rodin seized upon the life that was everywhere about him. He grasped it in its smallest details; he observed it and it followed him; he awaited it at the cross-roads where it lingered; he overtook it as it ran before him, and he found it in all places equally great, equally powerful and overwhelming. There was not one part of the human body that was insignificant or unimportant: it was alive."

"For years Rodin walked the roads of life searchingly and humbly as one who felt himself a beginner. No one knew of his struggles; he had no confidants and few friends. Behind the work that provided him with necessities his growing work hid itself awaiting its time. He read a great deal."

"Rodin dwelt in the books of the poets and gleaned from the past. Later, when as a creator he again touched those realms, their forms rose like memories in his own life, aching and real, and entered into his work as though into a home."

"Only his work spoke to him. It spoke to him in the morning when he awakened, and at even it sounded in his hands like an instrument that has been laid away. Hence his work was so invincible. For it came to the world ripe, it did not appear as something unfinished that begged for justification. It came as a reality that had wrought itself into existence, a reality which is, which one must acknowledge."

"Rodin's conception of Art was not to beautify or to give a characteristic expression, but to separate the lasting from the transitory, to sit in judgment, to be just."

"To Rodin the participation of the atmosphere in the composition has always been of greatest importance. He has adapted all his figures, surface after surface, to their particular space and environment; this gives them the greatness and independence, the marvelous completeness and life which distinguishes them from all other works. When interpreting nature he found, as he intensified an expression, that, at the same time, he enhanced the relationship of the atmosphere to his work to such a degree that the surrounding air seemed to give more life, more passion, as it were, to the embraced surfaces."

"... he worked incessantly; his life passed like a single working day."

"He was a worker whose only desire was to penetrate with all his forces into the humble and difficult significance of his tools. Therein lay a certain renunciation of Life, but in just this renunciation lay his triumph, for Life entered into his work."

Artists of all stripes swear by the need for solitude. A simple internet search will churn out 100s of quotes from well-known and accomplished individuals avowing the same. So there seems to be broad consensus for this idea. Indeed, the quest for self-knowledge, self-realization and self-awareness to any end across different spiritual traditions (e.g., achieving a deep understanding one's self, realizing that the self is an illusion, etc.)  emphasizes the need for some form of effortful distancing. Distancing oneself away from the collective via solitude or silence in order to be in a position to engage in deep self-reflection or inward monitoring. 

At the same time, meaningful collaboration and connection with thought-stimulating others has also been touted as exceedingly important in the creative process. Discourse allows for the exchange of ideas. Exposure to others' ideas increases our own conceptual knowledge. With that, the chance of our arriving at unusual combinations of ideas increases. It is little wonder then that the vital role of social spaces in facilitating discourse has been strongly advocated by several experts (e.g., Steven Johnson's "Where Good Ideas Come From"). This is in fact one of the grounds that have been put forward to explain greater levels of innovation and productivity in big cities (Bettencourt et al., 2007; 2011).

I think the following quotes by Rainer Maria Rilke capture some aspects of these two sides well.

• “The only journey is the one within.”
• “I want to be with those who know secret things or else alone.”
• “Make your ego porous. Will is of little importance, complaining is nothing, fame is nothing. Openness, patience, receptivity, solitude is everything."

 
Most of the discussion of what we "gain" in communication with others is on the increase of our knowledge by virtue of exposure to others' ideas (that resonate with us or fundamentally inform us in some way). We are mere RECIPIENTS in this constellation.

*********

Here is what's missing from this picture though.
What rarely, if ever, gets a mention much less a discussion is the fact that one also arrives self-knowledge as the AGENT of communication. This is exemplified in letters between artists and people close to them. Indeed, Rilke's outpourings of introspective wisdom (and inestimable generosity) were captured beautifully in his countless letters, the most well-known of which are the collection titled 'Letters to Young Poet'. Here are four further examples of powerful statements made by other profoundly reflective thinkers that speak to this idea.

1. (A quote by Michel de Montaigne)
“The most fruitful and natural exercise for our minds is, in my opinion, conversation.” 


2. (An excerpt from the 2014 Paris Review Interview of Adam Phillips by Paul Holdengraber)
PHILLIPS
"... a Welshman called Ernest Jones, had an idea that, interestingly, sort of disappeared. He believed that everybody’s deepest fear was loss of desire, what he called aphanisis. For him that’s the thing we’re most acutely anxious about, having no desire. People now might call it depression, but it wouldn’t be the right word for it, because he’s talking about a very powerful anxiety of living in a world in which there’s nothing and nobody one wants. But it can be extremely difficult to know what you want, especially if you live in a consumer, capitalist culture which is phobic of frustration—where the moment you feel a glimmer of frustration, there’s something available to meet it. Now, shopping and eating and sex may not be what you’re wanting, but in order to find that out you have to have a conversation with somebody. You can’t sit in a room by yourself like Rodin’s Thinker.

INTERVIEWER
Why not?

PHILLIPS
Because in your mind, you’re mad. But in conversation you have the chance of not being. Your mind by itself is full of unmediated anxieties and conflicts. In conversation things can be metabolized and digested through somebody else—I say something to you and you can give it back to me in different forms—whereas you’ll notice that your own mind is very often extremely repetitive. It is very difficult to surprise oneself in one’s own mind."


3. (An Interview with Martin Shaw, mythologist & storyteller.
Watch from the start. The moment arrives around the 1st minute.)


4. (An excerpt from Kahlil Gibran's 'Self-Knowledge')
And a man said, Speak to us of Self-Knowledge.
And he answered saying:
Your hearts know in silence the secrets of the days and the nights.
But your ears thirst for the sound of your heart’s knowledge.
You would know in words that which you have always known in thought.
You would touch with your fingers the naked body of your dreams.

And it is well you should.
The hidden well-spring of your soul must needs rise and run murmuring to the sea;
And the treasure of your infinite depths would be revealed to your eyes.
But let there be no scales to weigh your unknown treasure;
And seek not the depths of your knowledge with staff or sounding line.
For self is a sea boundless and measureless ...