Life, chemistry and cognition

As Shakespeare wrote in Much Ado About Nothing, “...there was never yet philosopher, That could endure the toothache patiently...” Indeed, perhaps the fundamental existential human experience is suffering. Under unbearable pain or distress, even the staunchest advocates of solipsism will eventually rescind their conviction that the world is only an illusion. What makes suffering so powerful in convincing us that we and the world are real is the fact that we experience it; we do not merely observe it. “I experience, therefore I am” would thus describe the indisputable human condition more appropriately than the classical statement “I think, therefore I am.” The latter statement was the foundation on which the seventeenth-century French philosopher René Descartes built his conception of the world. For Descartes (also known as Cartesius), thinking was the exclusive capacity of the incorporeal mind, the soul, which he defined as a thinking substance. Moreover, he claimed that only humans have a soul, and only they can reason; all other organisms, including monkeys as he explicitly posited, were mere automatons built of flesh and bones. Descartes did not deny life to animals or equate them with human-made machines, as has often been imputed to him. In contrast to inanimate machines, animals had corporeal spirits, which humans had too, and exhibited sensations and passions. Yet in Descartes’ view, the behaviour of non-human animals could easily be explained solely by the function and constitution of their organs; in contrast to humans, they did not have any capacity for pure thought free from natural impulses and passions. In his argument, he referred to the ancient Greek philosopher Epiktetos, who stated that you are not your body— your body is just finely moulded clay. To explain how the soul caused human reasoning, Descartes proposed an intriguing mechanism: the human mind commands the body. For some time, this dualism of mind and body was the intellectual basis on which philosophers, and later biologists, tried to explain consciousness and free will (Rose, 2005).