What is the relationship between being and thinking? Vittorino Andreoli approaches the question as a psychiatrist: thought is not an abstract entity but a biological function, one that arises from billions of neurons, synapses and neurotransmitters and is reshaped by experience through the plasticity of the brain. If the brain is matter, thought is what that matter produces in relation to others: we think because we are bodies embedded in an environment and in a history. Hence the open questions: how much of thinking we can observe and measure, how much lies beyond the reach of our instruments, why two brains with the same biology arrive at different thoughts. Thought not as a certainty, but as the living process that defines us.