Leonhard Euler quotes

Mathematicians have tried in vain to this day to discover some order in the sequence of prime numbers, and we have reason to believe that it is a mystery into which the human mind will never penetrate. (Leonhard Euler)
To those who ask what the infinitely small quantity in mathematics is, we answer that it is actually zero. Hence there are not so many mysteries hidden in this concept as they are usually believed to be.
Leonhard Euler
For since the fabric of the universe is most perfect, and is the work of a most wise Creator, nothing whatsoever takes place in the universe in which some relation of maximum and minimum does not appear.
Leonhard Euler
Madam, I have come from a country where people are hanged if they talk.
Leonhard Euler
Nothing takes place in the world whose meaning is not that of some maximum or minimum.
Leonhard Euler
Now I will have less distraction.
Leonhard Euler
A function of a variable quantity is an analytic expression composed in any way whatsoever of the variable quantity and numbers or constant quantities.
Leonhard Euler
Although to penetrate into the intimate mysteries of nature and thence to learn the true causes of phenomena is not allowed to us, nevertheless it can happen that a certain fictive hypothesis may suffice for explaining many phenomena.
Leonhard Euler
Logic is the foundation of the certainty of all the knowledge we acquire.
Leonhard Euler
It would be a considerable invention indeed, that of a machine able to mimic speech, with its sounds and articulations. ... I think it is not impossible.
Leonhard Euler
Of course, when the effective causes are too obscure, but the final causes are more readily ascertained, the problem is commonly solved by the indirect method. (Leonhard Euler)
The kind of knowledge which is supported only by observations and is not yet proved must be carefully distinguished from the truth; it is gained by induction, as we usually say. Yet we have seen cases in which mere induction led to error.
Leonhard Euler