Even facts become fictions without adequate ways of seeing the facts. We do not need theories so much as the experience that is the source of the theory. We are not satisfied with faith, in the sense of an implausible hypothesis irrationally held: we demand to experience the evidence.

Facts quite often, I fear to confess, like lawyers, put me to sleep at noon. Not theories, however. Theories are invigorating and tonic. Give me an ounce of fact and I will produce you a ton of theory by tea this afternoon. That is, after all, my job.

For reasons that are not entirely clear to me, Darwinism seems more in need of advocacy than similarly established truths in other branches of science. Many of us have no grasp of Einstein's theories of special and general relativity, but this does not lead us to oppose these theories.

It is often pointed out that chemists have failed in their attempts to duplicate the spontaneous origin of life in the laboratory. This fact is used as if it constituted evidence against the theories that those chemists are trying to test. But actually one can argue that we should be worried if it turned out to be very easy for chemists to obtain life spontaneously in the test-tube. This is because chemists' experiments last for years not thousands of millions of years, and because only a handful of chemists, not thousands of millions of chemists, are engaged in doing these experiments. If the spontaneous origin of life turned out to be a probable enough event to have occurred during the few man-decades in which chemists have done their experiments, then life should have arisen many times on Earth, and many times on planets within radio range of Earth.

There are many scientific theories that are in doubt. Even within evolution, there is some room for controversy. But that we are cousins of apes and jackals and starfish, let's say, that is a fact in the ordinary sense of the word.

One of the ways of stopping science would be only to do experiments in the region where you know the law. But experimenters search most diligently, and with the greatest effort, in exactly those places where it seems most likely that we can prove our theories wrong. In other words, we are trying to prove ourselves wrong as quickly as possible, because only in that way can we find progress.

Therefore psychologically we must keep all the theories in our heads, and every theoretical physicist who is any good knows six or seven different theoretical representations for exactly the same physics.

I am thinking of the Danish sculptor of great fame, Thorvaldsen, who chose to be buried in the midst of his work-not in a cathedral or a cemetery, but in a museum among the monuments of his own making- in the midst of his statuary; and there what he made and what he did with his life surrounds him. He did not theorize upon sculpturing, only, but with his hands and with his creative gift he fashioned those things and he lies there in the midst of his works, as we all shall do someday-and it will not be the theories or the discussions or the speculations or the set of principles or the set of commandments that shall save us. We shall be no better than we are. We are no better than the tithing we pay, no better than the teaching we do, no better than the service we give, no better than the commandments we keep, no better than the lives we live, and we shall have a bright remembrance of these things and we shall, in a sense, lie down in the midst of what we have done when that time comes.

I know that there may be several men who have charged the American Federation of Labor . . . to be against what they are pleased to call industrial unionism or the one big union, and I would venture to say that when they . . . consider this proposition outside of our union [Cigar Makers International Union] then they are industrialists; but when there is a proposal to open our doors and go into the highways and byways and organize these men and women against whom literally we are closing our doors, it is opposed.

All other men are specialists, but his specialty is omniscience.

I never guess. It is a shocking habit destructive to the logical faculty.

It is a fool's plan to teach a man to be a cur in peace, and think that he will be a lion in war.

All life on earth - everything from bacteria to mushrooms to hippos - shares an astonishing range of detailed biochemical similarities, including the structure of heredity in DNA and RNA, and the universal use of ATP as an energy-storing compound. Two possible scenarios, with markedly different implications for the nature of life, might explain these regularities: either all earthly life shares these features because no other chemistry can work, or these similarities only record the common descent of all organisms on earth from a single origin that happened to feature this chemistry as one possibility among many.

Biological evolution is a system of constant divergence without subsequent joining of branches. Lineages, once distinct, are separate forever. In human history, transmission across lineages is, perhaps, the major source of cultural change. Europeans learned about corn and potatoes from Native Americans and gave them smallpox in return.

Facts do not 'speak for themselves', they are read in the light of theory

Great thinkers build their edifices with subtle consistency. We do our intellectual forebears an enormous disservice when we dismember their visions and scan their systems in order to extract a few disembodied gems—thoughts or claims still accepted as true. These disarticulated pieces then become the entire legacy of our ancestors, and we lose the beauty and coherence of older systems that might enlighten us by their unfamiliarity—and their consequent challenge—in our fallible (and complacent) modern world.

Obsolescence is a fate devoutly to be wished, lest science stagnate and die.

Results rarely specify their causes unambiguously. If we have no direct evidence of fossils or human chronicles, if we are forced to infer a process only from its modern results, then we are usually stymied or reduced to speculation about probabilities. For many roads lead to almost any Rome.

The anatomical transition from reptiles to mammals is particularly well documented in the key anatomical change of jaw articulation to hearing bones. Only one bone, called the dentary, builds the mammalian jaw, while reptiles retain several small bones in the rear portion of the jaw. We can trace, through a lovely sequence of intermediates, the reduction of these small reptilian bones, and their eventual disappearance or exclusion from the jaw, including the remarkable passage of the reptilian articulation bones into the mammalian middle ear (where they became our malleus and incus, or hammer and anvil). We have even found the transitional form that creationists often proclaim inconceivable in theory — for how can jawbones become ear bones if intermediaries must live with an unhinged jaw before the new joint forms? The transitional species maintains a double jaw joint, with both the old articulation of reptiles (quadrate to articular bones) and the new connection of mammals (squamosal to dentary) already in place! Thus, one joint could be lost, with passage of its bones into the ear, while the other articulation continued to guarantee a properly hinged jaw. Still, our creationist incubi, who would never let facts spoil a favorite argument, refuse to yield, and continue to assert the absence of all transitional forms by ignoring those that have been found, and continuing to taunt us with admittedly frequent examples of absence.

The more important the subject and the closer it cuts to the bone of our hopes and needs, the more we are likely to err in establishing a framework for analysis.