A couple of stories in the media recently have highlighted the need for a more nuanced understanding of genetics. The first was about six months ago when Michael Gove’s outgoing special advisor Dominic Cummings published his ideas on education. Cummings cited studies that showed intelligence is highly heritable. Cummings then went on to argue that genetics should be used to inform education policy.
The second story was the spate of articles that accompanied the most recent study said to have identified genes linked to homosexuality. The question was raised as to whether couples should be allowed to select against embryos with these so called ‘gay genes.’
Advances in technology will make stories like these even more common. Genetics is currently benefitting from machines that can generate data on a previously unimaginable scale. Next generation (or second generation) machines can now sequence in hours what would have previously taken years. On the horizon is ‘third generation’ sequencing. This is technology that can read your genome in real time. This is the age of pricking your fingure, placing it into a machine and zing! Out pops your genome.
All this is wondrous and as genetics utilises new technology it will be said to cause just about everything, from heart disease to taste in music. The potential flood of genetic information means that we are all going to have to understand in much more detail what is meant by causation in genetics.
A useful place to start is Aristotle. Aristotle identified four types of cause: The material cause, the formal cause, the efficient cause and the final cause. It is the final cause that has taken such as hold in our psyches’ when thinking about genetics and it can be very misleading.
An event's final cause is the why of an event. It is the ultimate reason for something coming about. For a seed, it might be an adult plant. For a sailboat, it might be sailing. For human intelligence it might be a gene.
From the start, the language used to describe genetics has lent to them being perceived as the ‘final cause.’ If we go back to the very beginning, to the Eagle pub in Cambridge 1953, we can see James Watson proclaim he has found “the secret of life”
The imagery surrounding genetics that followed this original description has followed suit. To refer a trait as being “in your DNA” is common shorthand for describing the trait as being the very essence of who you are. A good example can be found here, where scientists claim to have discovered the ‘gene for love of the sea’. This is a great example of genes explaining the “why” and being viewed as the final cause.
This kind of thinking – explaining human traits by placing genes as the final cause- continued as genetics developed. Dawkins’ famous metaphor of the ‘selfish gene’ for example, relies of this type of teleological causation to make the analogy work. Genes are simply trying to replicate themselves faithfully, argues Dawkins, and we are simply replication machines. We are secondary to our genes’ purpose (faithful replication), which is the ultimate, final cause.
How genes cause the wide range of human traits cannot be explained by understanding causation in this way. There is rarely a ‘gene for’ anything. The causes of most human traits are not direct causes but systematic ones. Systematic causes can’t easily fit into any of Aristotle’s neat categories and because of this complexity, the language and imagery we use to understand genetics needs to evolve. It needs to evolve beyond the “secret of life” rhetoric that emerged when genetics was a nascent science and past the language of selfish genes or ‘genes for’ human traits.
As an example, one metaphor I like is that of our genome as a musical score. Bringing a musical score to life is a complicated process. How this process is done can lead to the same musical score being performed very differently. Furthermore the environment in which the music is played, both physically (concert hall, recording studio etc) and culturally (what audience is hearing the music) shapes how the music is heard and perceived. The musical score cannot be thought of as the final cause. It is not the ‘secret of music’ or the very essence of what music is. Despite this, music would not be possible without it. It is for these reasons I like it as a metaphor for our genome as it allows for complex relationships to be teased out.
As our knowledge and understanding of genetics advances we are all going to have to engage with it on both a personal and a policy level. We cannot avoid it, nor should we want to. If we’re going to make sensible decisions it is vital that we develop new and insightful language to understand what we mean by causation. Importantly this language must jettison any Aristotelian notions of genes as a final cause.