He entered the diocesan seminary in 1933 to study philosophy, graduating after two years with the thesis Das Erkennen der Existenz (The Knowledge of Existence) at the Pontifical Gregorian University in Rome.
Unsatisfied with the typical structure of theological study, he turned to the theories of Romano Guardini,[1] Maréchal, and other contemporary thinkers who promoted the existentialist aspect of philosophical research.
In his spare moments in the town, he started to read Vladimir Solovyov's works, which opened up to him infinite possibilities of a Christian philosophy built on the metaphysics of uni-totality.
Here, he decided to dedicate himself to spiritual theology, but he also intensely cultivated the study of dogmatic, as testified by the essay "Nauk Vladimira Solovjëva o razvoju dogme (Vladimir Solovyov’s doctrine on the evolution of dogma), published in the academic journal Bogoslovni vestnik.
He spent his novitiate in Pullach from 1946 to 1948, where he met father Albert Stögger, who was entirely devoted to the connection between his human richness and Saint Ignatius' spirituality.
With the collaboration of Stögger, he prepared research on Saint Ignatius’ interiority, published in the Revue d’ascetique et de mystique (Journal of Asceticism and Mysticism).
For a short time, Truhlar occupied the Chair of Mariology, but he later manifested to rector father Dezza the wish he could devote his research and his teaching exclusively to spiritual theology.
His teaching evolved, passing from the analysis of single letters from St Paul to Christian humanism, from exquisitely religious topics to gnosology and aesthetics.
Here, he published the Christological essay "Razvijanje in križanje človeške narave" (Development and crucifixion of human nature, 1956) and the theological reflection "Preobražanje sveta in beg pred njim" (Transformation of the world and escape in front of it, 1956–57).
In 1958, the collection of lyrics "Nova Zemlja" (The new land), and the essay "Krščanska doraslost" (Christian maturity) in Meddobje, was published in Buenos Aires.
At the end of 1974, at the age of 62 – after having spent 25 years in Rome devoted to an intense didactic and research activity[5] – Truhlar went back to his native country to Dravlje, a suburb of Ljubljana.
After his death, for the interest of his sister Zora and faithful student Lojze Bratina, an essay "Doživljanje absolutnega v slovenskem leposlovju" (The story of absolute in Slovenian literature), and two unpublished collections of lyrics "Motnordeči glas" (The murky red voice) and "Kri" (Blood) were published.