This idea comes from José Ortega y Gasset, a leading Spanish philosopher of the early 20th century. He was part of the 'Generation of '14,' a group of intellectuals who sought to modernize Spain. His philosophy argued that our immediate reality and circumstances are the starting point for all understanding, a concept this quote perfectly captures.

This quote has transcended academic philosophy to become a popular mantra for mindfulness in the Spanish-speaking world. It's frequently used in motivational contexts, self-help literature, and everyday conversation to remind people to focus on the here and now, rather than dwelling on the past or worrying about the future.

The quote's power lies in its absolute simplicity. The phrase 'lo único verdadero' (the only true thing) makes a bold, definitive statement. It dismisses the past as a mere memory and the future as pure potential, elevating the 'presente' as the sole plane of existence where life is actually lived. This reflects Ortega's existentialist leanings.