This book is for anyone who loves the world of ideas. The author, who is passionate about physical sciences, has tried to share his ideas. This book deals above all with philosophy, in a simple and accessible style. The author begins by discussing his conception of language, then extends his reflection to various philosophical subjects (happiness, suicide, war, etc.), medicine, and the physical sciences.A former student of the Louis Le Grand high school (Paris), Fabien Duval is passionate about physical sciences. This is his first book, in which he tries to share his ideas, and more particularly his passion for science.