Antonie van Leeuwenhoek Quotes

Early numbers are always wrong.

Every human creative endeavor is subject to mathematical law that you’re not always going to be right all the time.

I have lately examined water, in which beaten pepper was steeped, and found two sorts of animals for shape, and each of those sorts to contain greater and smaller kinds: the greater I supposed the elder, the less the younger.

Well, I'm a bacteriologist, you know. I live in a nine-hundred-diameter microscope. I can hardly claim to take serious notice of anything that I can see with my naked eye.

Did you ever look through a microscope at a drop of pond water? You see plenty of love there. All the amoebae getting married. I presume they think it very exciting and important. We don't.

I observed certain animalcules, within whole bodies I saw so quick a motion as to exceed belief; they were about the size of a large grain of sand, and their bodies being transparent, that the internal motion could plainly be seen. Among other things, I saw in the body of one of these animalcules a bright and round corpuscle, placed near the head, and in which a very wonderful swift motion was to be seen, consisting of an alternate extension and contraction. This particle I concluded to be the heart.

The 31th of May, I perceived in the same water more of those Animals, as also some that were somewhat bigger. And I imagine, that [ten hundred thousand] of these little Creatures do not equal an ordinary grain of Sand in bigness: And comparing them with a Cheese-mite (which may be seen to move with the naked eye) I make the proportion of one of these small Water-creatures to a Cheese-mite, to be like that of a Bee to a Horse: For, the circumference of one of these little Animals in water, is not so big as the thickness of a hair in a Cheese-mite.

Be approximately right rather than exactly wrong.

Each time I undertake to paint a picture I have a sensation of leaping into space. I never know whether I shall fall on my feet. It is only later that I begin to estimate more exactly the the effect of my work.

Examining this water...I found floating therein divers earthy particles, and some green streaks, spirally wound serpent-wise...and I judge that some of these little creatures were above a thousand times smaller than the smallest ones I have ever yet seen, upon the rind of cheese, in wheaten flour, mould, and the like.

Nothing, I believe, is so full of life under the microscope as a drop of water from a stagnant pool.

A chemist who does not know mathematics is seriously handicapped.

How incredibly far our lives drift from where we knew with all certainty they would go. How little today resembles what yesterday thought it would look like.

The unexpected is always likely to happen.

We are far too willing to reject the belief that much of what we see in life is random.

When you can measure what you are speaking about, and express it in numbers, you know something about it.

A fundamental principle of information theory is that you can’t guarantee outcomes… in order for an experiment to yield knowledge, it has to be able to fail. If you have guaranteed experiments, you have zero knowledge

What gets measured gets improved.

The method I take to do this is not yet very usual; for instead of using only comparative and superlative Words, and intellectual Arguments, I have taken the course (as a Specimen of the Political Arithmetic I have long aimed at) to express myself in Terms of Number, Weight, or Measure; to use only Arguments of Sense, and to consider only such Causes, as have visible Foundations in Nature.

It is also true that the less competent a person is in a given domain, the more he will tend to overestimate his abilities. This often produces an ugly marriage of confidence and ignorance that is very difficult to correct for.

Almost all thinking people agree that you should not have probability 1 (or 0) for any event, other than one demonstrable by logic, like 2 x 2 = 4.

[Donald] Trump is now. And we don't know what the rules are now.

I do not believe that I am now dreaming, but I cannot prove that I am not.