Phrenology was a very controversial subject. It was never accepted by the majority of scientists or by the church, and was seen as more of a ‘popular science’. And like so many popular sciences the protagonists did not use the same amount of energy to defend their science as they did to ‘prove’ it. This meant their arguments against those who opposed their ideas would often fall a bit short.

A strong argument used against phrenology was the tendency of the practitioners to flatter their subject. Others began to question whether subjects were being fooled by the ego-boosting skills of the phrenologists.

In 1821 a medical gentleman in Edinburgh fashioned a turnip into the nearest resemblance to a human skull. He sent it to Combe who detected the trick and returned the cast with this poem:

There was a man in Edinburg,

And he was wond’rous wise;

He went into a turnip-field,

And cast about his eyes.

And when he cast his eyes about,

He saw the turnips fine;

“How many heads are there,”says he,

‘That likeness bear to mine!”

“So very like they are indeed,

No sage, I’m sure, could know

This turniphead that I have on

From those that there do grow.”

He pull’d a turnip rom the ground;

A cast from it was thrown:

He sent it to a Spurzheimite,

And pass’d it for his own.

And do, indeed, it tryly was

His own in every sense;

For CAST and JOKE alike were made

All at his own expense.

Combe may have taken the situation light heartedly, but it was obvious that people were starting to realize how much of a joke the subject was.

There was a large split in the Edinburgh Phrenological Society when an emphasis on “morality without religion” became apparent among George Combe and his colleagues. They were seen as trying to undermine The Bible. The evangelical members left when they banned the discussion of theology in the Society and began to adhere to materialism.

Elaborate theories about the evolution of the brain were opposed by people who were also members of the Plinian Society. This was a club at the University for students interested in natural history, of which Charles Darwin was a member.

Phrenology started to be seen as, and named, a pseudoscience, which is something presented as science with no real scientific truth or method.

The last meeting in 1870 marked the end of the Edinburgh Phrenological Society.

Phrenology was openly opposed by Francis Jeffrey, the editor of the Edinburgh Review and Sir William Hamilton, a highly acclaimed philosopher and once Professor of History at Edinburgh.

Francis Jeffrey published a review of Combe's ‘System of phrenology’ gathering almost all of the previously applied arguments to discredit phrenology for his review. This was seen as a huge blow to the phrenologists.

In 1827 Hamilton lectured against phrenology to a huge audience in the Edinburgh Assembly Rooms.

This led to a backlash however, when Combe gave his refutation elsewhere to a much larger audience of 600.

Hamilton even conducted his own experiments to test the accuracy of phrenology. Over a period of several months, Hamilton inserted wires and needles into the brains of chickens, rabbits and cats in his garden.

The phrenologists responded to this challenge by condemning it as animal cruelty.

The hostility between these professionals may have added glamour to the subject for a while, but without valid rebuttals and with people starting to loose some interest in the subject, there is no doubt it played a large part in the eventual downfall of phrenology.