Most of the vices and mortal sins condemned today correspond to inclinations that were purely adaptive or at least harmless in primitive man.

It is a good morning exercise for a research scientist to discard a pet hypothesis every day before breakfast. It keeps him young.

Historians will have to face the fact that natural selection determined the evolution of cultures in the same manner as it did that of species.

Every man gets a narrower and narrower field of knowledge in which he must be an expert in order to compete with other people. The specialist knows more and more about less and less and finally knows everything about nothing.

I have found the missing link between the higher ape and civilized man; it is we.

We do not take humor seriously enough.

Evil, by definition, is that which endangers the good, and the good is what we perceive as a value.

We had better dispense with the personification of evil, because it leads, all too easily, to the most dangerous kind of war: religious war.

Most of the vices and mortal sins condemned today correspond to inclinations that were purely adaptive or at least harmless in primitive man.

Truth in science can be defined as the working hypothesis best suited to open the way to the next better one.

I believe that present day civilized man suffers from insufficient discharge of his aggressive drive.

Barking dogs occasionally bite, but laughing men hardly ever shoot.

The bond with a true dog is as lasting as the ties of this earth will ever be.

'I don't need brains,' says the billionaire contemptuously. 'I'm brainy enough myself!' The broker cries out in desperation, 'What, in heaven's name, do you want?' 'Goodness,' is the answer.

Ethologists are often accused of drawing false analogies between animal and human behaviour. However, no such thing as a false analogy exists: an analogy can be more or less detailed and, hence, more or less informative.

From a neighbour, I got a one-day-old duckling and found, to my intense joy, that it transferred its following response to my person. At the same time, my interest became irreversibly fixated on water fowl, and I became an expert on their behaviour even as a child.

I consider early childhood events as most essential to a man's scientific and philosophical development.

I grew up in the large house and the larger garden of my parents in Altenberg. They were supremely tolerant of my inordinate love for animals.

I owe undying gratitude to my patient parents.

In the course of evolution, it constantly happens that, independently of each other, two different forms of life take similar, parallel paths in adapting themselves to the same external circumstances.

Practically all animals which move fast in a homogeneous medium have found means of giving their body a streamlined shape, thereby reducing friction to a minimum.

The father-mother family with two children isolated in a city flat is already insufficient.

There is indeed the possibility that the evolutionary process has, in gray antiquity, bred into us an excess of aggression.

When I was about ten, I discovered evolution by reading a book by Wilhelm Boelsche and seeing a picture of Archaeopteryx.

Whenever we find, in two forms of life that are unrelated to each other, a similarity of form or of behaviour patterns which relates to more than a few minor details, we assume it to be caused by parallel adaptation to the same life-preserving function.

The human mind in taking us down the path of technocracy has become the adversary of life itself and collaterally the adversary of the human soul.

Man has been driven out of the paradise in which he could trust his instincts.

The cat is a wild animal that inhabits the homes of humans.

The bond with a dog is as lasting as the ties of this earth can ever be

Roosevelt's magic lay in one facet of his personality: He knew how to take the risk. No other man in public life I knew could so readily take the challenge of the new.

Man was born free, and he is everywhere in chains.

Photography is a major force in explaining man to man.

The world is... the natural setting of, and field for, all my thoughts and all my explicit perceptions. Truth does not inhabit only the inner man, or more accurately, there is no inner man, man is in the world, and only in the world does he know himself.

I am neither a child, a young man, nor an ancient; nor am I of any caste.

I want the municipality to be a helping hand to the man with a desire of sympathy, to help the fallen when it is not in their power to help themselves.

I always looked for a man to rescue me and bring me happiness. I bought into that myth, of course, and looked for my own Prince Charming.

A desire to be observed, considered, esteemed, praised, beloved, and admired by his fellows is one of the earliest as well as the keenest dispositions discovered in the heart of man.

Nonviolence is a powerful and just weapon. which cuts without wounding and ennobles the man who wields it. It is a sword that heals.

Let me first state that I believe that marriage is a sacred union between one man and one woman.

A man must be strong in that profession, he must have vigor of body and mind, yet I am all out of breath if I walk up a hill; I have not the heart to crush even a fly.

An intelligent man is sometimes forced to be drunk to spend time with his fools.

I believe that if a man does a job as well as a woman, he should be paid as much.

For a man to strike any women is most brutal, and I, as well as everyone else, think this far worse than any attempt to shoot, which, wicked as it is, is at least more comprehensible and more courageous.

There is always a type of man who says he loves his fellow men, and expects to make a living at it.

A man may be in as just possession of truth as of a city, and yet be forced to surrender.

The bravest sight in the world is to see a great man struggling against adversity.

If a man is dumb, someone is going to get the best of him, so why not you? If you don't, you're as dumb as he is.

Happy the man who has been able to learn the causes of things.

Work is not man's punishment. It is his reward and his strength and his pleasure.