In my thesis, I explore the concept and construct of a meaningful life using an interdisciplinary approach that integrates philosophical and psychological perspectives.

I argue for the conceptualization of "meaningfulness as positive impact" while scrutinizing the reliance on individual intuitions in philosophical discourse. I advocate for supplementing traditional philosophical methods with experimental and cross-sectional (qualitative and quantitative) approaches to gain a deeper understanding of what constitutes a meaningful life.

Additionally, my research critically evaluates the tripartite psychological view of meaning in life, which measures this psychological state through dimensions of purpose, coherence, and significance. I propose the inclusion of a potential fourth dimension: the impact on others. Furthermore, I investigate the relationship between meaning in life and psychological well-being, particularly focusing on eudaimonic well-being, which extends beyond mere satisfaction and positive emotions. My thesis suggests integrating assessments of meaningfulness into models of well-being for a more comprehensive evaluation.

I present philosophical arguments and psychometric analyses to differentiate between the belief in the meaning of life and the psychological experience of meaning, demonstrating that the experience of meaning correlates with well-being indicators such as life satisfaction, positive emotions, and prosocial impact, while belief in meaning is closely tied to religiosity and spirituality.

Moreover, I explore the folk concept and everyday experiences of meaning through qualitative, quantitative, and experimental studies.

Overall, my thesis defends the philosophical standpoint that life can be deemed meaningful when individuals pursue specific purposes involving self-transcendent activities that result in positive impacts on others. I also propose that the psychological experience of meaning in life should be conceptualized and measured as a multidimensional construct encompassing purpose, coherence, significance, and impact. Lastly, I offer a theoretical framework to elucidate the unity and interactions among these diverse dimensions.

In an addendum, I discuss the positive and negative aspects of meaningfulness, illustrating how the pursuit of meaning can enhance mental health and well-being but also potentially lead to the endorsement of conspiracy theories or extremist ideologies.