Breinchemie verklaar nie die een wat dink nie
Kort antwoord: Die neurowetenskap wys dat elke gedagte en gevoel saamgaan met iets in die brein. Dit wys nie dat die gedagte niks anders is as die chemie nie. En as al ons denke net chemie was, sou ons geen rede hê om enige gedagte te vertrou nie, ook nie dié een nie.
Jy luister na ‘n gewilde podcast. Die gas is ‘n neurowetenskaplike. “Verliefdheid is dopamien en oksitosien,” sê hy. “Jou geloof is ‘n patroon in jou temporale lob. Daar is geen siel nie, net ‘n brein wat die storie van ‘n ‘ek’ vertel.”
En jy sit met die vraag: as dit waar is, wie luister nou eintlik na die podcast?
Wat waar is
Begin by wat waar is, want dis baie. ‘n Kopbesering kan iemand se persoonlikheid verander. Medikasie kan ‘n depressie lig. Op ‘n skandeerder kan jy sien hoe ‘n deel van die brein aktief word wanneer iemand bang is.
‘n Christen moet dit verwelkom. Die Bybel het nooit gesê die mens is ‘n gees wat los van sy liggaam rondsweef nie. Die Heidelbergse Kategismus praat in sy heel eerste vraag van jou troos “met liggaam en siel” (Vraag 1). Jy is een mens, nie ‘n spook in ‘n masjien nie.
Saam is nie dieselfde nie
Maar kyk mooi na wat die skandeerder wys. Dit wys dat vrees en ‘n sekere breinpatroon saam voorkom. Dit is ‘n korrelasie. Om daaruit af te lei dat die vrees niks anders as die patroon is nie, is ‘n sprong. Die skandeerder maak nie daardie sprong nie.
Die filosoof David Chalmers het in 1995 gewys hoe groot die sprong is. Hy het onderskei tussen die “maklike” probleme van bewussyn, soos hoe die brein inligting verwerk, en die “moeilike” probleem: hoekom voel dit van binne af soos iets om koffie te proe? Jy kan elke neuron van iemand wat koffie drink, karteer en elke sein beskryf. Jou beskrywing sal volledig wees, en die smaak van koffie sal nêrens daarin staan nie. Dertig jaar later is daardie probleem nog nie opgelos nie.
Die draai
Nou die eintlike knoop. Die neurowetenskaplike op die podcast wil hê jy moet sy argument oorweeg en tot die gevolgtrekking kom dat dit waar is.
Maar chemiese reaksies is nie waar of vals nie. Hulle gebeur net. Asyn wat met koeksoda bruis, is nie reg of verkeerd nie. As sy oortuiging “daar is geen siel nie” net ‘n reaksie in sy brein was, sou dit nie ‘n insig wees nie, maar ‘n uitset. Dan het jy geen rede om dit te glo nie, en hy ook nie.
Om te kan sê “my gedagtes is net chemie” en dit te bedoel, het hy presies nodig wat hy ontken: ‘n verstand wat redes kan weeg en waarheid kan soek. Die klassieke tradisie, van Thomas van Aquino af, het die siel nooit as ‘n ekstra onderdeel in die kop gesien nie. Die siel is wat jou liggaam ‘n lewende, denkende mens maak.
Volgende keer
As iemand sê jou brein is net chemie, vra vriendelik: “Is daardie gedagte ook net chemie? Hoekom moet ek dit dan glo?”
Sy brein sal antwoord. Maar hy sal dit bedoel.
Gaan dieper
Brain chemistry does not explain the one who thinks
Short answer: Neuroscience shows that every thought and feeling goes together with something in the brain. It does not show that the thought is nothing but the chemistry. And if all our thinking were just chemistry, we would have no reason to trust any thought, this one included.
You are listening to a popular podcast. The guest is a neuroscientist. “Falling in love is dopamine and oxytocin,” he says. “Your faith is a pattern in your temporal lobe. There is no soul, just a brain telling itself the story of an ‘I’.”
And you are left with the question: if that is true, who is actually listening to the podcast?
What is true
Start with what is true, because a lot is. A head injury can change someone’s personality. Medication can lift a depression. On a scanner you can see a part of the brain become active when someone is afraid.
A Christian should welcome this. The Bible never said man is a spirit floating free of his body. In its very first question the Heidelberg Catechism speaks of your comfort “in body and soul” (Question 1). You are one person, not a ghost in a machine.
Together is not the same
But look carefully at what the scanner shows. It shows that fear and a certain brain pattern occur together. That is a correlation. To conclude that the fear is nothing but the pattern is a leap. The scanner does not make that leap.
The philosopher David Chalmers showed in 1995 how big the leap is. He distinguished the “easy” problems of consciousness, such as how the brain processes information, from the “hard” problem: why does it feel like something, from the inside, to taste coffee? You could map every neuron of someone drinking coffee and describe every signal. Your description would be complete, and the taste of coffee would appear nowhere in it. Thirty years later that problem has not been solved.
The turn
Now the real knot. The neuroscientist on the podcast wants you to weigh his argument and conclude that it is true.
But chemical reactions are not true or false. They just happen. Vinegar fizzing with baking soda is neither right nor wrong. If his conviction “there is no soul” were only a reaction in his brain, it would not be an insight but an output. Then you would have no reason to believe it, and neither would he.
To say “my thoughts are just chemistry” and mean it, he needs exactly what he denies: a mind that can weigh reasons and seek the truth. The classical tradition, from Thomas Aquinas on, never saw the soul as an extra part inside the head. The soul is what makes your body a living, thinking person.
Next time
When someone says your brain is just chemistry, ask kindly: “Is that thought also just chemistry? Then why should I believe it?”
His brain will answer. But he will mean it.