What can be Tested

Theories regarding the physical behavior of objects can be readily tested. Predictions about the force of gravity can be made, based on theory. These predictions can then be tested and verified or rejected. The tests can be repeated on many occasions and by many people. One example is the theory that gravity acts with the same force on objects regardless of their mass. In other words objects will fall at the same speed regardless of weight. This theory is counter intuitive. Aristotle had believed that heavier objects fell faster than light objects. This, whilst seeming to make sense, does not actually happen in reality. Very light objects which are affected by air resistance do fall more slowly, but if you remove air and repeat the experiment in a vacuum, a feather will fall at the same speed as a brick. This aspect of gravity was most famously demonstrated by Galileo. Interestingly Aristotle did believe that truth needed to be tested against experience, unlike his teacher Plato. The problem was that he never seems to have got round to testing this theory. This one small example shows just how useful science can be. Very often things are not as our intuition would suggest. By testing the premises on which our intuitions are based, we discover truth and expand human knowledge.

From a strictly logical point of view the example above can never be shown to be absolutely true. No matter how many times we try this experiment, there is always the possibility that the next time we try it, it will not work. Just because the Sun has risen every morning in human history, it does not follow that it will definitely rise tomorrow. Just because every time we test the speed of falling objects they fall at the same rate, regardless of weight, it does not follow that it will always be true. As is often said in financial services, ‘Past performance does not necessarily predict future results’. However, the regularity with which this experiment has been tried and results have matched exactly to the predictions, mean that it is as close to truth as you can get. It is an extremely high probability that is more successful at predicting behavior than any other theory we have. The problem with not being able to describe something as absolutely true is a problem of language, not a problem with reality.

Science tests language against reality, it does not test reality against language. If a contradiction exists in reality, it is the language that is faulty, not reality. When scientific theories perceived light to be either a wave or a particle, the tests which showed it was both, did not prove that reality was wrong, they showed that the theories were wrong. Waves and particles were not contradictory in their nature. When theories are tested and found to be true, they are true, not absolutely true. If a thing cannot be described as absolutely true, this is not the same as saying it is false. If something is scientifically true, it simply means that something is true in all circumstances that we know of. If a scientific theory changes through an increase of knowledge, reality doesn’t change. A test which shows the effect of gravity will not stop working if a new theory of gravity appears. It would allow us to make more precise measurements and predictions. When people reject truth because it is not absolute truth, they abandon knowledge that works. They abandon reality for language.