JM: I’d certainly be happy to obtain therapy to halt or even reverse the aging process (give me back my hair!), and I am sure most people would similarly like to stay alive fit and healthy for much longer. It is happening already and I believe the end point will eventually be reached when people will not need to age or die unless they wish to. I’d certainly embrace such a world.
MLU: Finally, Johnjoe, I hear that you are working on a new book about Ockham's Razor. Would you care to give us an introduction?
JM: I’ve already mentioned my favourite medieval thinker, William of Ockham. He is famous today for his razor, Ockham’s Razor, which is the principle of parsimony that states that we should prefer simpler explanations over complex ones: ‘entities should not be multiplied beyond necessity’. The more I consider this principle the more convinced I am that it is one of the most fundamental tools of science, perhaps even its most important tool. Consider the creationists. They are notoriously difficult to prove wrong because they can invent elaborate creationist ‘explanations’ of the all the evidence or facts you can muster. The final argument against their preposterous theories rests finally with Ockham’s Razor: it is much simpler to assume that one explanation -- evolution -- is real than to accept the multitude of elaborate mechanisms of floods, God’s intervention, etc., to explain the fossil and molecular record.
Ockham’s Razor is fundamental to any scientific theory. Consider for a moment those famous laws of motion described by Sir Isaac Newton. His third law states that “for every action there is an equal and opposite reaction.” Every time an object is pushed then the object pushes back with a force that is precisely equal to the applied force. The law is fundamental to our understanding of even the simplest mechanics. Kick a rock along the beach with your bare foot and your toes will experience the rock’s reaction: it kicks back. A fish propels itself through the water by using its fins to push water backwards (the action); the water reacts by pushing the fish forward (the reaction). A bird beats its wing against the air and the air reacts by pushing the bird skyward. The principle also underpins most mechanical technology from the simple catapult to the motor car or space rocket.
But, there is another law that could account for all these facts just as well as Newton’s. It is, for every action there is an equal and opposite reaction, plus a pair of demons who push with equal and opposite force on either side of the object experiencing the action.” So now alongside Newton’s force we have demonic forces that push with equal and opposite strength so that their net effect is zero: they cancel each other out. Like Newton’s law, this demon-assisted law is also consistent with experience, experimentation and perfectly accounts for the action of animal locomotion and mechanical devices. It is just as good at ‘fitting the facts’ as the original theory. But it is burdened with additional entities.