The philosopher Baruch Spinoza (1632-1677) said that joy is not a fleeting state of mind but an emotion that comes from knowledge and reason, and that it becomes a political and ethical tool to transform society. Four centuries have passed and the world does not offer many reasons for joy, between the climate crisis and the rise of hate speech, but Francisco Javier Vera is determined, he says, to "resume the philosophy of the Dutchman Baruch Spinoza" and use joy to change the world. "It is not about denying reality, but about assuming it to try to imagine possible alternative futures not from anger or uncertainty but from joy," he argues.