What is truth? This is a question for philosophy, science and religion, or rather these words provide different questions to philosophy, science and religion. I feel that one thing that is missing from many arguments is a clear understanding of what is, and what isn’t possible to argue about. 

There is a difference between arguing about whether greenhouse gases cause a warning planet, about whether solar cycle effects are increasing or decreasing that warming, about what we should do about it. There’s a difference between arguing about whether God exists, or whether a homosexual can be a Christian, or whether gun restrictions should be introduced. And these differences are because they are asking for a different kind of truth. 

 I know people who enjoy philosophy and will ask questions about whether mathematics is discovered or invented, about whether “2+2=4” is fundamentally true or axiomatic, about whether there is anything true except “I think therefore I am”. I am not writing this blog for those people. Their definition of “truth” is very narrow and will not encompass scientific truth. That the Earth goes round the sun is, for them a “theory”. If we argue at this level it will take us too long to understand the difference between the questions “what causes climate change?” and “what shall we do about it?”. I am a scientist, not a philosopher and while I acknowledge the questions exist, I do not propose to discuss them further here. And there is a reason for this. If you hear those arguments without having heard their context you will get confused. I think this is part of what leads to arguments about the “theory of evolution” or the “greenhouse effect theory”. 

Consider gravitational theory (Newton’s and Einstein’s). This is not true in the sense that 2+2=4, or in the sense that “this blog’s name is scientificquaker”. But it is effectively true. We can use it to make predictions, it is tested to the limits of our experimental and observational capability, we have underpinning theoretical explanations of “how it works” which can, themselves, make predictions we can test. 

I have heard it said that “Einstein proved Newton wrong” and this used as an argument for why scientists may also be wrong on climate change. But Einstein didn’t prove Newton wrong – and we still use Newtonian mechanics to launch a rocket. But we use Einsteinian mechanics to consider the workings of the clocks in the GPS satellites. What we must understand is that both Newtonian and Einsteinian mechanics are our models which explain, as far as they can, the physical workings of the universe. They aren’t the workings of the universe but they are models which help us understand what we otherwise can’t understand. We also know – because we’ve tested it – how far those models can go and where we don’t know. Einstein’s theory includes Newton’s theory. It didn’t correct it, but extended it to where it didn’t apply. Most of the time Newton’s theory works well and when it doesn’t we can use Einstein’s extension. We also know how deeply we’ve tested Einstein’s theory (and we continue to probe beyond those borders (http://m.phys.org/news/2016-04-einstein-theory-relativity-satellite.html).

Scientific truth therefore is something where we have a working model that has an underlying theoretical basis (we can explain why), is backed by observation/experiment and which makes meaningful predictions we can test by observation/experiment. We generally expect scientific truth to expand with time, that the new theory encompasses the old and expands its remit or the level of detail. It is rare for a new theory to contradict an old one. 

It is not that individual scientists aren’t biased, don’t make mistakes, but when there is scientific consensus, the ideas have been thoroughly tested. (I am talking about the physical sciences here – what I know about – I think some aspects of biological science and many aspects of social science need a more nuanced argument). 

When there isn’t scientific consensus we realise there are aspects we don’t understand. Those different viewpoints are helping us explore different aspects. Scientists may debate for years, even decades, but there is a recognition that we are all chasing a single, as yet unknown truth. Most scientists know when we haven’t and when we have reached it, though being human can be upset when their way of understanding is superseded. Some discussions are debated for thirty years – until the last generation has retired off…

Maybe it’s because such debates look, from the outside, so similar to debates about whether God exists or whether socialism or capitalism is better for society (blogs to come!) that nonscientists don’t understand the difference. 

There’s a t-shirt slogan that says “the nice thing about science is that it’s true whether or not you believe in it”. Scientists love it – and it tries to express what I’ve discussed here, which scientists find baffling to understand why everyone else doesn’t get this intuitively. They often go on to assume it’s because everyone else is stupid. And that’s why I don’t like the slogan.