In the heat of speculation or of love there may come moments of equal perfection, but they are very unstable. The reason and the heart remain deeply unsatisfied. But the eye finds in nature, and in some supreme achievements of art, constant and fuller satisfaction. For the eye is quick and seems to have been more docile to the education of life than the heart or the reason of man, and able sooner to adapt itself to the reality. Beauty therefore seems to be the clearest manifestation of perfection, and the best evidence of its possibility.
The ideal man is the non-attached man. Non-attached to his bodily sensations and lusts. Non-attached to his cravings for power and possessions. Non-attached even to science and speculation and philanthropy.
But by far the greatest hindrance and aberration of the human understanding proceeds from the dullness, incompetency, and deceptions of the senses; in that things which strike the sense outweigh things which do not immediately strike it, though they be more important. Hence it is that speculation commonly ceases where sight ceases; insomuch that of things invisible there is little or no observation.
A zeal for different opinions concerning religion, concerning government, and many other points, as well of speculation as of practice; an attachment to different leaders ambitiously contending for pre-eminence and power; or to persons of other descriptions whose fortunes have been interesting to the human passions, have, in turn, divided mankind into parties, inflamed them with mutual animosity, and rendered them much more disposed to vex and oppress each other than to co-operate for their common good. So strong is this propensity of mankind to fall into mutual animosities, that where no substantial occasion presents itself, the most frivolous and fanciful distinctions have been sufficient to kindle their unfriendly passions and excite their most violent conflicts. But the most common and durable source of factions has been the various and unequal distribution of property.
Where speculation ends — in real life — there real, positive science begins: the representation of the practical activity, of the practical process of development of men. Empty talk about consciousness ceases, and real knowledge has to take place. When reality is depicted, philosophy as an independent branch of activity loses its medium of existence.
By no amount of reasoning can we altogether eliminate all contingency from our world. Moreover, pure speculation alone will not enable us to get a determinate picture of the existing world. We must eliminate some of the conflicting possibilities, and this can be brought about only by experiment and observation.
Medicine is a strange mixture of speculation and action. We have to cultivate a science and to exercise an art. The calls of science are upon our leisure and our choice the calls of practice are of daily emergence and necessity.
One of the difficulties facing a serious philosopher is that he must keep his eyes on so many subjects. He must recognize the fruits of division of labor and yet try to appreciate what is going on. On the one hand, he must be critical of many moves in the past, such as a deductive approach to what is, which have shown themselves to be mistaken. On the other hand, he must have a keen eye for genuine puzzles and problems. I, myself, concentrated on the nature of human knowing, on the status of value in the world, and on the traditional mind-body problem. I did not think that philosophy just by itself could solve these problems. The increase of knowledge would help. But I thought that philosophy could make a cooperative contribution by what has come to be called categorial analysis. Philosophy usually had a long historical perspective in these matters. It could keep its eye on the nature of the puzzle. In short, philosophy never meant to me uncontrolled speculation about a supposed transcendental realm, as positivists always assume. I was quite early naturalistic and even materialistic in my outlook. I just wanted to fit things together in an intelligible way.
It always bothers me that according to the laws as we understand them today, it takes a computing machine an infinite number of logical operations to figure out what goes on in no matter how tiny a region of space and no matter how tiny a region of time ... I have often made the hypothesis that ultimately physics will not require a mathematical statement, that in the end the machinery will be revealed and the laws will turn out to be simple. ... But this speculation is of the same nature as those other people make - 'I like it', 'I don't like it' - and it is not good to be too prejudiced about these things.
Run the tape again, and let the tiny twig of Homo sapiens expire in Africa. Other hominids may have stood on the threshold of what we know as human possibilities, but many sensible scenarios would never generate our level of mentality. Run the tape again, and this time Neanderthal perishes in Europe and Homo erectus in Asia (as they did in our world). The sole surviving human stock, Homo erectus in Africa, stumbles along for a while, even prospers, but does not speciate and therefore remains stable. A mutated virus then wipes Homo erectus out, or a change in climate reconverts Africa into inhospitable forest. One little twig on the mammalian branch, a lineage with interesting possibilities that were never realized, joins the vast majority of species in extinction. So what? Most possibilities are never realized, and who will ever know the difference? Arguments of this form lead me to the conclusion that biology's most profound insight into human nature, status, and potential lies in the simple phrase, the embodiment of contingency: Homo sapiens is an entity, not a tendency.