The development of science is often portrayed as a conflict between science and religion, between the natural and the supernatural. But it was equally, if not more so, a conflict with Aristotelian concepts: a change from Aristotle’s emphasis on why to a dominant role for how. To become the mainstream, science had to overcome resistance, first and foremost, from the academic establishment and only secondarily from the church. The former, represented by the disciples of Aristotle and the scholastic tradition, was at least as vociferous in condemning Galileo as the latter. Galileo, starting from when he was a student and for most of his career, was in conflict with the natural philosophers. (I decline to call them scientists.) His conflict with the church was mostly towards the end of his career, after he was fifty and more seriously when he was nearing seventy. The church itself even relied on the opinions of the natural philosophers to justify condemning the idea the earth moved. In the end science and Galileo’s successors won out and Aristotle’s natural philosophy was vanquished: the stationary earth, the perfect heavens (circular planetary orbits and perfectly spherical planets), nature abhorring a vacuum, the prime mover and so on. For most of these it is so long and good riddance. So why do philosophers still spend so much time studying Aristotle? I really don’t know.
However, Aristotle did have a few good ideas whose loss is unfortunate. The baby was thrown out with the bath water, so to speak. One such concept, although much abused, is the classification of causes given by Aristotle. The four types of causes he identified are the formal, material, effective and final causes. He believed that these four causes were necessary and sufficient to explain any phenomena. The formal cause is the plan, the material cause is what it is made of, the effective cause is the “how”, and the final cause is the “why”. If you think in terms of building a house the formal cause is the blueprint, the material cause is what it is built of (the wood, brick, glass, etc.), the effective causes are the carpenters and their tools (are hammers obsolete?) and the final cause is the purpose the house was built for.
Aristotle and his medieval followers emphasized the final cause and pure thought. Science became established only by breaking away from the final cause and the tyranny of “why”. The shift from concentrating on pure thought and the final cause (why) to concentrating on observations and effective causes (how) was the driving factor in the development of science. Science has now so completely swept Aristotle aside that, at the present time, only the effective cause is considered a cause in the “cause and effect” sense.
However, in dealing with human activities all four of these types of causes are useful. For example consider TRIUMF where I work. The formal cause is the five-year plan given in a brilliantly written (OK. I helped write it and they pay my salary so what else could I say) 800-page book that lays out the program for the current five years and beyond. The material cause is what TRIUMF is built of (many tons of concrete shielding among other things). The effective cause is the people and machines that make TRIUMF work. The final cause is TRIUMF’s purpose as given in the mission and vision statements. A similar analysis can be done for any organization. The usefulness of the final cause concept is shown by it being resurrected in good management practice under the heading of mission and/or vision statements.
Now, when we go from human activity to animal activity, we lose the formal cause. Consider a bird building a nest. The material cause is what the nest is built of, the effective cause is the bird itself and the final cause is to provide a safe place to raise its young. But the formal cause does not exist. It is doubtful the bird has a blueprint for the nest; rather the nest is built as the result of effective causes – the reflexive actions of the bird. No bird ever wrote an 800-page book outlining how to build a nest. Just as well, or the avian dinosaurs (otherwise known as birds) would have gone extinct along with the non-avian ones.
A similar analysis exists for simpler organisms. A recent study of yeast showed why (in the sense of the final cause) yeast cells clump together: to increase the efficiency of extracting nutrients from the surroundings. Thus in dealing with human, animal or even yeast activities, science can and does answer the why or final cause question. In the case of the yeast the effective cause would be the method the yeast cells used to do the bonding and the material cause the substances used for the bonding.
When we go from animate to inanimate we lose, in addition to the formal cause, the final cause. Aristotle explained the falling of objects in terms of a final cause: the objects wanted to be at their natural place at the center of the universe, which Aristotle thought was the center of the earth. The reason they speed up as they fell was they became jubilant at approaching their natural place (I am not making that up). Newton, in contrast, proposed an effective cause: gravity. There was no goal, ie final cause, just an effective cause. A river does not flow with the aim of reaching the sea but just goes where gravity pulls. Similarly with evolution by natural selection, it has no aim but just goes where natural selection pulls. This freaks out those people who insist on formal and final causes. With much ingenuity, they have tried to rectify the situation by proposing formal and final causes: intelligent design and theistic evolution respectively. Intelligent design posits that at least some of the structures found in living organisms are the result of intelligent design by an outside agent and not the result of natural selection while theistic evolution posits that evolution was controlled by God to produce Homo Sapiens. Neither has been found to increase the ability of models to make accurate predictions; hence they have no place in science. It is this lack of utility not the role of a supernatural agent that leads to their rejection as science.
To summarize: for the activities of living things, science can and does answer the why question and assigns a final cause. However, for non-living things science has not found the final cause concept to be useful and has eliminated it based on parsimony. Aristotle, his followers and disciples made the mistake of anthropomorphizing nature and assigning to it causes that are only appropriate to humans or, at best, living things.
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