“It will, of course, be understood that directly or indirectly, soon or late, every advance in the sciences of human nature will contribute to our success in controlling human nature and changing it...”

“Nowhere more truly than in his mental capacities is man a part of nature.”

“Human beings are accustomed to think of intellect as the power of having and controlling ideas and of ability to learn as synonymous with ability to have ideas. But learning by having ideas is real...”

“Just as the science and art of agriculture depend upon chemistry and botany, so the art of education depends upon physiology and psychology.”

“Psychology is the science of the intellects, characters and behavior of animals including man.”

“Human folk are as a matter of fact eager to find intelligence in animals.”

“When man will return to nature, nature will return to him.”

“The sky is an enormous man.”

“When the full-grown poet came,Out spake pleased Nature (the round impassive globe, with all its shows of day and night,) saying, He is mine;But out spake too the Soul of man, proud, jealous and unr...”

“Even the Middle Ages, which condemned and punished animals in due form, was in this way much closer to them than we are. They held them to be guilty: which was a way of honoring them. We take them ...”

“The clearest way into the Universe is through a forest wilderness.”

“Until one has loved an animal, a part of one's soul remains unawakened.”

“Watch out for intellect,because it knows so much it knows nothingand leaves you hanging upside down,mouthing knowledge as your heartfalls out of your mouth.”

“How very paltry and limited the normal human intellect is, and how little lucidity there is in the human consciousness, may be judged from the fact that, despite the ephemeral brevity of human life...”

“Ideas are the source of all things”