To Zara Yaqob – a seventeenth-century Ethiopian rationalist, the heart is, broadly, a symbol of wisdom. But surprisingly, in analytic terms, the heart is, for him, also a symbol of reason.

That is: 

1. The Heart is a symbol of reason.

2.  Humans can reason.

3. They reason with the heart.

Before Yaqob, ancient Egyptians also embraced the heart as a cradle of thought. They mummified the human heart and sucked out the brain. The heart captured their imagination and stimulated their reasoning power and wisdom. It is said that hearts were lifted and soaked in wines and herbs, preserved for worship by saints. The Egyptians were cardiocentrists. They considered the brain worthless, and worshipped the heart instead.  

Aristotle too thought of the heart as the symbol of thinking. As the son of a biologist, and influenced by his father, and accustomed to shrewd observation, he dissected and studied animal hearts, his Historia Animalum and De Patrubs Animalum, are a wealth of empirical evidence and detailed documentation of the structure and function of the heart. He disagreed with his teacher Plato that the heart is a cushion, by arguing that, in fact, the heart is the seat of the soul and, therefore, the seat of wisdom and rationality.