Subjective vs objective

In recent years there has been much debate over the validity of objective knowledge. The word 'objective' comes from medieval Latin and means 'the things presented to the mind,' but in common parlance it refers to the common sense notion that there are things in the world that have a separate existence from us. A horse is a horse to both me and thee. Not only is it common sense, but all rational thought, including science depends on it. An object, therefore, is something external to the self.

On the other hand, 'subjective' refers to inner feelings. A horse is a horse, but how I feel about a horse may not be the same to me or thee. To a jockey, a horse is valued according to how well it can run. To a horsefly, a horse is a banquet. What the horse thinks is hard to tell.

Certain schools of thought in Western philosophy have used the latter observation to cast doubt on the validity of objective knowledge. They are especially fond of trotting out, not a horse, but a broomstick, and partially submerge it in a pool of water. "Yikes," they cry. "Our eyes deceive us. They tell us that the broomstick is bent where it enters the water. So much for objectivity. So much for the value of our observations." The fact that human beings are perfectly capable of compensating for the refraction of light is forgotten in the exciting glow of self-congratulation. How clever they are. Dumbfounded by this brilliant insight, another school of philosophers, the post modernists, labouring mightily, took the logic one step further. Obviously, if we cannot trust our perceptions then there is no absolute truth. One man's truth is just as good as another's. Eureka! Thus, by a commodius vicus of recirculation we arrive at Howth Castle, now known as cultural relativism. Relativism is a word made magic by the theories of a Swiss customs clerk.

Einstein's theories of relativity, incomprehensible to most of us, and the even more baffling theories of quantum mechanics summed up in a document called the Copenhagen Convention, delivered a more telling blow to the idea of objective reality. Alas, they seemed to say, and proved it beyond doubt to all the world at Hiroshima and Nagasaki, nothing is what it appears to be, and it is all but impossible for the human mind to grasp reality except through the workings of increasingly esoteric mathematical formulations. But still, they needed Hiroshima to prove the theories. It's pretty hard to argue against the objective truth of two incinerated cities.

But the objective world is only knowable to us through our senses. This was already noticed by Plato and his followers. Plato imagined a higher existence where the perishable and imperfect things known to our senses had a perfect, immutable and ageless reality, knowable by us not through our senses but through reason. Running with this idea, his successors over the following centuries imagined more and more elaborate spheres of existence, guarded over by hierarchies of angels or other fantastic beings. This became the accepted science of all the civilizations of the ancient world and lasted until the time of Copernicus, Galileo, Kepler, and others who showed that the stars in the heavens were not arranged in the perfect spheres that the theory predicted. The earth and human beings were no longer at the centre of creation but merely insignificant specks in a vast ocean. From then on the prestige of our reasoning faculty waned while the importance of observations based on measurements gained importance. Numerical reasoning became the sine qua non of scientific reasoning, but the only way to establish the truth of the mathematics was by reference to the observable world.

We have never stopped puzzling over this issue. An English philosopher had a few things to say

about it.

All the objects of human reason or enquiry may naturally be divided into two kinds, to wit, Relations of Ideas, and Matters of fact. Of the first kind are the sciences of Geometry, Algebra, and Arithmetic ... [which are] discoverable by the mere operation of thought ... Matters of fact, which are the second object of human reason, are not ascertained in the same manner; nor is our evidence of their truth, however great, of a like nature with the foregoing.

Put into the formula that became known as Hume's Fork, it comes out like this:

• Statements about ideas - these are analytic, necessary statements that are knowable a priori.
• Statements about the world - these are synthetic, contingent, and knowable a posteriori.

Which line of reasoning led to this conclusion:

If we take in our hand any volume; of divinity or school metaphysics, for instance; let us ask, Does it contain any abstract reasoning concerning quantity or number? No. Does it contain any experimental reasoning concerning matter of fact and existence? No. Commit it then to the flames: for it can contain nothing but sophistry and illusion.

Here in a nutshell we have the foundational reasoning behind modern scientific atheism. As a statement of how the game of science should be played it is admirable. How much can we learn about the workings of nature by sticking to those two rules? Quite a lot. It's an extremely valuable and beneficial tool that has taken us from the beginning of time to the edge of the universe, from the unimaginably large scale of galaxies to the infinitesimally small scale of the atom. It's shown us that matter and energy are only different phases of the same thing. It is an incredible achievement. But when it is claimed that what science reveals is all there is to know then that is not a statement of science but of metaphysics, and nothing about metaphysics can be known in principle by use of the scientific method.

The application of scientific principles as a practical and powerful tool of inquiry has provided us with unprecedented material well-being. The conversion of science as a tool into science as a philosophy is perhaps the most important factor in explaining why humanity went insane in the 20th century.