In our post on anthropomorphism, we discussed benefits and pitfalls of ascribing human motivation to subatomic particles.
There is a related but different phenomenon, which can occur when popular culture appropriates a scientific idea. It often happens when science uses an everyday word for a technical concept – people may then be forgiven for generalising the scientific meaning to any everyday situation in which the word might occur. A classic example is Newton’s Third Law, when stated as “every action has an equal and opposite reaction”. The problem here is the word ‘action’. Newton did not mean ‘action’ in this sense to mean ‘a thing that is done’. He had a specific meaning in mind – what science now calls a ‘force’. In hindsight, the 17th century could hardly have chosen a less convenient word – ‘action’ is so general a word nowadays, that there’s hardly a situation in which it can’t be applied in a misleading way! And even worse, the word ‘action’ has a modern, technical meaning in physics that is not the same as ‘force’!
Consider this excerpt from a spirituality website:
“Newton’s third law of motion tells us that every action has an equal and opposite reaction. In physics, this means that when an object collides with a target, there is an equal force going into and away from the target at the same time. The law of Karma generalizes this rule to all areas of life, beyond just physical motion… We experience the truth of this whenever we give someone else an encouraging word or a helping hand. We send out a force of compassion towards them by what we say and do and instantly we feel that same compassion in ourselves in the form of a good feeling.”
Now, this may well be good life advice; surely no-one can object to sending out a force of compassion to others. The Law of Karma may even be real (apart from the bit where Isaac Newton is mentioned). I am not an expert in systems of spirituality, and I am not claiming that there isn’t a valid Law of Karma.
But I am saying the following… the life advice given above has absolutely nothing to do with Newton’s Third Law; to generalise Newton’s Third Law in this way is not logically valid. There is no need to invoke Newton – being nice to people is a good enough idea not to need any justification (ironically Newton was famously not always that nice and compassionate himself!). Newton’s sentence has got nothing to do with human motivation and spirituality. It applies to physical forces between pairs of objects. The Law of Karma might be a really good idea but it is not the same class of statement as a Law of Physics.
Right, having got that off my chest, and just to give Newton his due, we should probably quote him more accurately from his Laws of Motion:
- “Lex III: Actioni contrariam semper et æqualem esse reactionem: sive corporum duorum actiones in se mutuo semper esse æquales et in partes contrarias dirigi.”
- “ Law III: To every action there is always an equal and opposite reaction: or the forces of two bodies on each other are always equal and are directed in opposite directions.”
My Latin is non-existent, so I’m trusting the online translation I found, but it seems that the second half of the full law is the real, technical, non-everyday meaning – which would never be falsely generalised! Therefore, I propose a total ban on phrasing Newton’s Third Law as “every action has an equal and opposite reaction” so that nobody can be fooled into falsely applying it to spurious situations. I agree that “If object A exerts a force on object B, then object B exerts an equal and opposite force on object A” isn’t as sexy. But:
- It might stop a lot of ‘inappropriate generalization’
- It’s more precise and easier to understand for modern students learning science with modern language
- It would prevent student misunderstanding of many common science education resources. It is common to employ Newton’s Third Law in the ‘soon-to-be-banned form’, without explaining that ‘action’ means ‘force’. Typically the word ‘action’ has not appeared before, and is not explained. Afterwards, we revert to talking about forces and never mention ‘action’ again. It is quite difficult for a student to make the link between force and action themselves
- It is what Isaac Newton meant
I nearly didn’t write this post. I don’t want to come across as stirring up an argument where there doesn’t need to be one. But on reflection, I actually think this matters, and it isn’t just harmless wordplay. In the case of the Law of Karma, there is probably no harm done – the worst that can happen is that someone misunderstands physics. But what if people try to justify less benign opinions by falsely invoking science? There have been instances of that through history that were definitely not harmless.
Science could sometimes do a better job of thinking about the words and phrases that move into common currency. See our post ‘Who first split the atom?’ Can you think of other examples of technical language being used in a misleading way? Post in the comments, or tweet @SciByDegrees.