Authentic Existence: Bridging Phenomenology and Stoicism

. The aim of this article is to provide comparative research of the concept of authentic existence in Stoicism and Phenomenology. The analysis in the article is carried out by comparing select authors’ understanding of a few key concepts which appear to be the most alike: authentic and inauthentic existence, personal renewal, seeking cosmologic framework for ethics, being part of community, and the role of death in shaping awareness of authentic existence. The analysis concludes that there are various degrees of convergence in all concepts considered in the article, which allows the argument that despite substantial differences between philosophies, concepts of authentic existence of Stoicism and Phenomenology at times have compatible aspects, and even complement each other. is attained, if he has fulfilled the good for which nature designed him at birth. And what is it which this reason demands of him? The easiest thing in the world, – to live in accordance with his own nature. But this is turned into a hard task by the general madness of mankind; we push one another into vice.


Introduction
An analysis on contiguity between philosophies of Stoicism and Phenomenology is relatively rare. One of the reasons is Stoicism's heavy emphasis on ethics, while Husserl's writings on ethics have only recently been revealed in full. In the meantime, both philosophies, in their own ways and contexts, address the notion of authentic and inauthentic existence (though Stoics do not use the term, the concept itself is recognizable).
The aim of the article is to provide comparative research of the concept of authentic existence in Stoicism and Phenomenology. The article argues that there are points of affinity between concepts of authentic existence of Stoicism and Phenomenology, which at times seem compatible, even complementing each other. The research is carried out by comparing understanding of concepts in both philosophies, which seem to have the best potential for the convergence: that is, authentic and inauthentic existence itself, and its supplementary concepts of personal renewal, seeking cosmologic framework for ethics, being part of community, and the role of death in shaping awareness of authentic existence.
To say "concept of authentic existence in Stoicism and Phenomenology" entails various degrees of generalization. Neither Stoicism, nor Phenomenology is a unified, straightforward school of thought, much less so as it concerns the ethics part of Phenomenology. Indeed, in the case of Phenomenology, it would require analyzing each individual author's perspectives, and attempt to determine some shared understanding between them of each concept. Since that would go beyond the scope of the article, only select key philosophers' understanding of these concepts are explored.
Within the tradition of Phenomenology, two of its prominent representatives -Edmund Husserl and Martin Heidegger both have their own perspectives on what it means to live authentically, which constitutes the spectrum of Phenomenological thought for the purposes of this article. During his lifetime Husserl published very little on ethics, most of his thoughts on ethics have been preserved through his manuscripts and lecture courses. Ullrich Melle identifies three periods when "Husserl worked rather intensively on axiology and ethics" (Melle 2002: 230), and concludes that "Husserl's later ethical thought is much broader in scope than his early ethics, and is often connected with theological and metaphysical considerations <...>, but it is not shaped into a coherent and systematic unity" (Melle 2002:241). Views from Husserl's later ethics (periods between 1920Husserl's later ethics (periods between -1925Husserl's later ethics (periods between and 1930Husserl's later ethics (periods between -1935 and its interpretations, are applied in the article on the concepts of personal renewal, seeking cosmologic framework for ethics, and being part of community. Meanwhile, Heidegger's ontology has ambiguous relations with ethics ("Indeed, no thinker of the 20th century has been so thoroughly interrogated as Heidegger himself regarding the existence (or lack) of "ethics" in his thought" (Buckley 2002: 197)). However, in his opus magnum Being and Time, Heidegger's concept of authenticity features throughout the work, which serves as another source of Phenomenological perspective in the article, by contributing and broadening insights into authentic existence, being part of community, and awareness of death.
Classically, ancient Stoicism is divided into three periods. Only original texts from the third, Roman period of Stoicism, have survived somewhat in full. That is why the approaches of Epictetus, Marcus Aurelius, and Seneca prevail in today's reading of Stoicism. The late Stoa period focuses on ethics and its practical application in one's everyday life. As Pierre Hadot has argued, "Such is the lesson of ancient philosophy: an invitation to each human being to transform" herself (Hadot 1999: 275).That is fully applicable to the Roman Stoics, whose teachings are used to ground Stoic interpretations of the concepts considered in the article. Additionally, Stoic ethics continue to attract followers. A noticeable wave of interest in Stoicism has developed from the last decades of the 20 th century to this day (for the purposes of this article called "contemporary Stoicism"). Contemporary Stoicism is understood as a bid to adapt or update ancient Stoicism, to bring it closer to the worldviews and practicalities of the 21 st century. Where applicable, to enrich the dynamics of discussion between two philosophies, contemporary debate of modern interpretation of Stoicism is included.

Authentic and Inauthentic Existence
What does concept of authentic and inauthentic existence comprise of for Heidegger? And what does it mean to live authentically for Stoics? Since other concepts explored in the article are supplemental to the concept of authentic existence, these are the questions that require an answer in the first place.
In Being and Time, Heidegger describes inauthentic existence as a "situation" where all humans find themselves in the world, that is, inauthentic existence is one's principal mode of being in the world. This is the "situation" where the "I" in her everydayness is inescapably together with the "they": ""In authenticity" <...> amounts rather to a quite distinctive kind of Being-in-the-world -the kind which is completely fascinated by the 'world' and by the Dasein-with of Others in the "they"" (Heidegger 2001: 220).Thus, inauthentic existence is an existence dispersed within the "they" world, when the "I" does not stand on her own.
Authentic existence, on the other hand, comes with realization that "We are ourselves the entities to be analysed. The Being of any such entity is in each case mine" (emphasis in original, Heidegger, 2001: 67). This leads to distinguishing the "they" world and one's they-self "from the authentic Self-that is, from the Self which has been taken hold of in its own way" (emphasis in original, Heidegger 2001: 167). Yet, it is not an either-or situation. Quite the contrary: humans always retain their inauthentic existence, while authentic existence comes (if at all) on top of that as its modification (Heidegger 2001: 168). Meanwhile, Heidegger does not attach any moral superiority to authentic existence, "the inauthenticity of Dasein does not signify any 'less' Being or any 'lower' degree of Being" (Heidegger 2001: 68). The process towards authenticity overall could be described as personal transformation when one is able to take a step back and reflect on her own they-self. While authentic existence, as taking ownership of one's life, has a clear resemblance in Stoicism, Heidegger's notion that authentic existence is neither better, more valuable, nor that it leads to a proper life over the inauthentic existence, represents a sharp divergence from the Stoic view. For Heidegger, a shift towards the authentic mode of being is not actively pursued: "Authenticity arises as both an accomplishment on Dasein's part and an acceptance," because "authenticity is not something to be achieved, but rather something that one "undergoes"" (Buckley 2002: 203). What we are undergoing towards authenticity, is experiencing a call from our conscience, it is inside us. Heidegger (2001: 320) says: "'It' calls, against our expectations and even against our will. <...> The call comes from me and yet from beyond me" (emphasis in original). Our conscience calls us to open up to the authentic existence when we are anxious and experience tension with our being in the "their" world, and when we acknowledge the ontological meaning of our temporality or being toward death. The process itself is more of "letting-oneself-be-summoned" (Buckley 2002: 201) (which likely derives from the moral neutrality of authentic existence), rather than a rational decision to upgrade (not only transform) one's inauthentic existence, as would be the case for Stoics. For Heidegger, it is resoluteness, that characterizes one's listening to this inner call, followed by the full engagement to the authentic mode of being or, in other words, resoluteness as "Dasein's own potentiality-for-Being" (Heidegger 2001: 405).
" [Y]ou're a fragment of God," says Epictetus (2014: 86), and that defines the Stoic interpretation of authenticity. Reason is a fragment of God in a human body. Not a resemblance of God, but a fragment. Reason is what unites humans and God, so the task for humans is to use their reason, and only through reason could the authentic existence be achieved. Thus, the Stoic solution is based on rationality, rather than the consciousness that is preferred in Phenomenological tradition. Seneca in a few lines summarizes the Stoic interpretation of authentic and inauthentic existence: For man is a reasoning animal. Therefore, man's highest good is attained, if he has fulfilled the good for which nature designed him at birth. And what is it which this reason demands of him? The easiest thing in the world, -to live in accordance with his own nature. But this is turned into a hard task by the general madness of mankind; we push one another into vice. (Seneca 2013:110) To unpack this quote, I first discuss what it means to live in accordance with nature, and then turn to the concept of inauthentic existence, which Seneca boldly calls "the general madness of mankind".
The ultimate goal of Stoic ethics is to become a sage. There are two elements to work on to achieve this goal: first, live according to nature, and second, observe the four core virtues: courage, justice, practical wisdom, and temperance. One could live in accordance with nature by studying, understanding, and accepting the world (that is -logos, nature), its laws, necessities, and fate. There are three types of nature a Stoic should understand and follow: cosmic nature, human nature, and one's unique individual nature. To become the sage or at least to strive for it requires a deliberate and persistent effort. This is the life of a philosopher (in a broad sense -anyone who lives by a Stoic teaching), or as Husserl portrayed it, "the "philosophical" form of existence: freely giving oneself, one's whole life, its rule through pure reason or through philosophy" (Husserl 1970: 8). It is a life of conscious choices and reflection, including what Hadot calls "spiritual exercises," or specific practices of how to reflect upon one's life and apply Stoic tenets into the conduct of life. The goal to live a philosophical life towards wisdom needs to be actively pursued to achieve it.
The general outline of the Stoic concept of inauthentic existence is compatible with Heidegger's views. In both, inauthentic existence is marked with inertia, being satisfied and in comfort with everydayness. The persistent effort a Stoic needs to progress towards wisdom is not an easy task, and that is why some people choose not to pursue this road to happiness (and self-sufficiency, becoming the sage), focusing on bodily or external goods instead (like career, money, pleasure, etc.). However, for Stoics, living the philosophical life is undoubtedly morally superior (being consciously chosen as good) over everydayness. Those who live inauthentic lives Stoics sometimes call "slaves" (being a slave to one's unreasonable emotions, opinions of others, etc.), "layman", or use contemptuous terms like Seneca did calling inauthentic existence "madness". Subsequently for the Stoics it is an either-or choice. As Epictetus put it: "you must devote your efforts either to your ruling centre or to external things; in other words, you must assume the part either of a philosopher or of a layman" (Epictetus 2014: 173).
To sum up, despite the obvious divergences, there are points of affinity, not in the way a "transfer" from inauthentic to authentic mode of being occurs, but in relation to both states of existence. Namely, inauthentic existence is roughly similar in Heidegger's Being and Time, and Stoic thought. Additionally, there is a comparable understanding of what it is to live authentically: it is to live consciously, reflecting on one's own life, taking ownership of one's life. Stoicism in its teaching goes a step further by not only defining what authentic existence is but also by offering practical tools to be applied, that is -how to live authentically (or progressing towards wisdom, to use Stoic terminology). Stoic practical exercises to live a philosophical life seem to be compatible once one achieves Heidegger's authentic existence.

Personal Renewal
While seeking contiguity between ethics of Stoicism and Phenomenology, the next concept to explore is a Stoic teaching on progress which corresponds, to a considerable degree, to Husserl's ideas on personal renewal.
According to Stoics, to become the sage requires a long-term persistent effort. Stoics describe the sage as a person who is making progress, and it is part of the concept of ethical development. First, the ethical development is constant self-improvement because "Nothing great comes into being all at once" (Epictetus 2014: 36). And second, all humans are capable of progressing towards a virtuous life, and living in accordance with nature.
To make progress, tenets of Stoic teaching (like how to deal with unreasonable emotions, and how to distinguish -and act upon -what is in one's power and what is not) should be put to use on a daily basis. The daily use should be followed by reflection on results, making adjustments, if necessary, and applying again, then --repeated until one achieves a smooth flow of life. Ultimately, it will affect everything one does: "putting his guiding principles into action in relation to anything that he has to deal with <...> this, then, is the person who is truly making progress" (Epictetus 2014: 12).
This aspect of the concept of ethical development, namely, to apply Stoicism to everything one does, has been further evolved in contemporary Stoicism by Lawrence Becker. Becker elaborates the tenet by applying the context of one's whole life to everything one does, stating that: "Ideal agency is comprehensive; it aims to integrate and optimize the success of every single thing we do, in relation to everything else we do or might do, over our entire lives" (Becker 2017: 156). As shown below, this interpretation of the concept of ethic development in contemporary Stoicism, by looking at the context of one's whole life, has a strong resemblance to Husserl's thought.
Husserl's ideas on personal renewal are expressed in articles published in the journal Kaizo in 1923-1924. Though they are characterized as expressing "a radical ethical rationalism" (Melle 2002: 242), and as such, interpreted as atypical for Husserl's later ethical thought, the ideas expressed in the articles come close to those of Stoicism. Consider this short summary of the Kaizo articles by Sophie Loidolt: the Kaizo articles' "main topic of renewal as the 'chief theme of ethics', which demands a radical, ever renewing beginning of a new life under rational self-rule and the ideal of perfection" (emphasis in original, Loidolt 2012: 9). It is not only primacy of reason, but also self-improvement as a constant process, and rigorous application that align Stoic concept of ethical development with Husserl's ideas on personal renewal. Also, with the Kaizo articles, Husserl's ethics come to examine the entire human (ethical) life, which has its replica in the ancient approach to ethics (the philosophical form of existence).
"Renewal" is a phenomenon which accompanies one's taking ownership (or selfdetermination in this case) over her own life, and reconsidering their entire life (past, present and future), in the framework of a human (ethical) life as a whole. Irene Breuer describes the process in the following way: Husserl stresses here the importance of a critical self-reflection or self-evaluation to the constitution of an ethical life insofar as this life presupposes a radical self-critique through which the personal I can arrive at a higher form of consciousness and thus reorganise its whole life. Husserl calls this process "renewal [Erneuerung]" (Breuer 2019: 29). As in Stoicism, everything one does is affected, resembling the Stoic image of the flow of life. Marco Cavallaro and George Heffernan, when describing a Husserl's happy individual, put it as follows:"all my beliefs and position-takings (Stellungnahmen), as well as all my volitions and actions, produce "the harmony of a whole life"" (Cavallaro, Heffernan 2019: 363). What is more, Husserl's ideas on personal renewal include a deliberate decision for a renewal, as well as permanent effort from a person -both aspects also required from a Stoic to make progress. The following account of Husserl's idea of renewal may as well be attributed to a person who is embarking into Stoicism: "The decision for such a renewal is, according to Husserl, a decision for a radical new beginning, for a new life of rational self-rule. It implies a determined struggle with irrational impulses, bad habits, and false ideals, a rigorous pulling-oneself-together" (Melle 2002: 242). For Husserl personal renewal is an ideal, perfection which one can strive for and sometimes approximate, very much like the sage is for Stoics.
To conclude, Husserl's ideas of personal renewal, as expressed in the Kaizo articles, feature strong convergence with the Stoic concept of ethical development. With Husserl's emphasis on rationality throughout the process, he is closer to Stoic thought than to Heidegger's shift towards the authentic mode of being by means of "letting-oneself-besummoned" and subsequent resoluteness.

Seeking Cosmologic Framework for Ethics
Both philosophies recognise that ethical life requires a broader explanation in the worldview of an individual, which provides "why" answers (that is, meaning) to ethical outlooks. Husserl's cosmologic framework for an ethical life is not systematically developed, as is the case for his entire later ethics, and there are skeptical opinions that Husserl came up with these ideas to allow his other concepts to hold together 1 . However, in the context of Stoic ethics, and, especially, contemporary debate, Husserl's approach on how to substantiate cosmologic framework for ethics could add a worthwhile insight.
In his later ethics, Husserl moves on to combine his ideas of ethics based in reason (as discussed above) with ethics based in love. The notion of love, or absolute ought, represents not only rational, but fully personal, involvement. "[C]ore phenomenon which guides the unfolding of Husserl's later ethics: It is the person who experiences a call (a certain vocation) and who answers to it by willingly dedicating and orientating her life to/towards it" (emphasis in original, Loidolt 2012: 9). A call (like for Heidegger -the innermost call) which contains individualized vocation or absolute ought for a particular individual (Hart 2015: 257), is enabled by love. Answering the call "requires us to "live in ethical seriousness"" (Breuer 2019: 26).
Against this backdrop -the commitment to ethical life -Husserl turns his gaze to the scientific view of indifference towards the world: [I]f history has nothing more to teach us than that all the shapes of the spiritual world, all the conditions of life, ideals, norms upon which man relies, form and dissolve themselves like fleeting waves, that it always was and ever will be so, that again and again reason must turn into nonsense, and well-being into misery? Can we console ourselves with that? Can we live in this world, where historical occurrence is nothing but an unending concatenation of illusory progress and bitter disappointment? (Husserl 1970: 7) If the world is 'senseless', fulfilling the absolute ought would be pointless as well. That is why, for the ethical life to be worthwhile, it requires the arrangement of the world which would provide a meaning to the submission of one's life to the absolute ought.
To ground this arrangement of the world, Husserl (2014: 317 (n.1)) comes up with the notion of a "rational belief" defined as follows: "If I have the slightest real possibility that the world "complies" with human purposes, then I must take this presumption as a certainty and act accordingly" (as translated in Cavallaro, Heffernan 2019: 376). Thus, Husserl's rational belief or faith contains an invitation to believe in the responsive world, because only under these circumstances is an ethical life feasible.
To overcome the subjectivity of the individual absolute ought, Husserl introduces a divine element. Consequently, it is God that provides a context and meaning to the absolute ought and ensures that the world is responsive to human deeds. Husserl envisages divine involvement in the world as a framework for self-realization: "In order to be able to believe in myself and my true self and the development toward it, I have to believe in God" (Husserl Ms. A V 21: 24b/25a, now in Husserl 2014, as translated in Melle 2002. To complete the construct of responsive divine arrangement of the world, Husserl supplements it with something very well understandable for Stoics -that the world is a whole: "through a universal causal regulation, all that is together in the world has a universal immediate or mediate way of belonging together; through this the world is not merely a totality [Allheit] but an all-encompassing unity [Alleinheit], a whole" (emphasis in original, Husserl 1970: 31). It is a combination of the (1) rational faith in (2) responsive divine unified arrangement of the world that gives meaning to one's ethical life (fulfilling the absolute ought).
For ancient Stoics, ethical tenets are interrelated with the broader context provided by their physics or cosmology. The Stoic God is "immanent in the cosmos as its soul or rational, controlling principle" (White 2003: 137). Thus, God (logos) rules the world and ensures the underlying principles and structure of the world. It is not a religious God either, rather a philosophical God, whose existence is derived in Stoic theory by (among other things) the evidence of animate, rationally ordered cosmos (Diogen 1995: 316). One of the underlying principles of the world is that the world is just. Humans should regard gods as beings "who exist and govern the universe well and justly" (Epictetus 2014: 295). Justice of the world order has twofold importance regarding humans' ethical life: first, it provides a model to strive for (to live in accordance with), and second, an individual can rely on the order of the world, because it is just. For Stoics, everything exists for the whole and the whole is an absolute harmony of its different parts. Thereby, the cosmologic framework of ethical life is an individual's coherence with the order of the world and having own's role and responsibilities within the whole.
Yet, today Stoic cosmology may sound archaic. There has been continuous eagerness of the practitioners and interpreters of Stoicism to disentangle ethics from Stoic physics. For contemporary followers of Stoicism, this is a subject of a lively debate -what is the role of Stoic cosmology (logos, Zeus, fate, etc.) in Stoic ethics? Can it be replaced or abandoned for Stoicism to be applicable in the 21 st century? For example, an early, thorough philosophical work on rejuvenating Stoicism, is Becker's A New Stoicism of 1997. The first item that needed an update, in Becker's view, is ancient cosmology. Becker invites to reinterpret Stoic physics in accordance with the facts about the universe that scientists recognize today. That is, from "follow the nature" to "follow the facts" (Becker 2017: 46-47). According to Becker, the contemporary scientific worldview insists that the cosmos is indifferent to human's ethical life (and thus deny just order in the universe), and therefore, does not support ideas of ancient Stoic cosmology. Husserl faced a similar hurdle, but still came up with rational justification of why there should be the responsive divine universe in order to have a complete view on one's ethical life.
While searching for the cosmologic framework for an ethical life, both teachings at points come close: reassuring arrangement of the world (responsive, just); divine framework of ethical life (rational faith in philosophical God); and world as a whole. Husserl's reply to a scientific worldview of cosmic indifference (which was not available for ancient Stoics, at least not as developed), might be appealing (give constructive ideas) for contemporary Stoics to reconcile contemporary science with ancient Stoic teaching.

Being Part of Community
Both philosophies emphasize that authentic existence does not equate with life isolated from society. Quite the opposite -being part of society is an important building block of their ethics. For Stoics it is their teaching about cosmopolitism, for Heidegger -as discussed before, "Being-with is an existential constituent of Being-in-the-world" (Heidegger 2001:163), and for Husserl -it is a community of love. Although their similarity is seemingly more superficial than it appears at the outset.
Stoic cosmopolitism derives from the concept that there is a fragment of God in every human -a feature that unites all humans. Thus, Epictetus and Marcus Aurelius called all humans citizens of cosmos. Because all humans share reason, people should respect each other -as another fellow bearer of God's fragment. As Epictetus put it: "can't you put up with your own brother, who has Zeus for his father, and is, so to speak, born of the same seed as you, and is of the same heavenly descent?" (Epictetus 2014: 34). Thereby, humans form a community of rational beings. Though Stoics are supposed to focus on their own progress, it is done by living within families, society, and fulfilling their own individual (social) roles and pursuits. Stoics argue that involvement within society, while working on one's own progress, is beneficial (enabling the individual to progress and exercise virtues like justice and temperance) and natural (humans are social beings).
Stoic Hierocles (a lesser-known representative of the late Stoa) has expressed concisely the Stoic principle of the involvement within society as a concept of circles of moral concern. Hierocles's (in Ramelli 2009: 91) circles of moral concern start with the self. Then, they spread to close family, starting with one's child, because attachment and responsibility to one's child is natural and one should act upon it: "as soon as one has a small child, it's no longer in our power not to love it and take care of it" (Epictetus 2014: 51). In this way the absorption on self, and only self, is broken, and others are included into a Stoic's circles of moral concern. From close family, the circles go on to other relatives, neighbours, countryman, until one understands that there is no rational stopping line, and all the human race is included. Thus, ethical development of a Stoic is not achieved in isolation from others, rather in being an active and responsible part of the whole.
For Husserl, an individual's ethical prospects are inextricably linked to her engagement within society. Truly being "me" is achievable only by living a life as part of a community: "my being an ethical person is strictly related to how I behave with respect to others, my fellow human beings. <...> [F]irst and foremost, my family, friends, colleagues, and, further removed, my ancestors (Stamm), nation, and so forth (Cavallaro, Heffernan 2019: 370). Fully in line with the Stoic's circles of moral concern, Husserl (2014: 384) states that one's child is the closest to her, thus, from one's child starts an extension of one's ethical approach to life onto others.
Husserl expands the notion of being a part of community by other relevant components like recognizing that others are "I"s as well, how these others are proceeding in attaining their true "I", and what kind of community they form together. The highest form of the social interaction is "community of love" 2 . Love is acknowledging others as "I"s: "Love for Husserl intends the unique uniqueness of the Other" (Hart 2015: 258). Within the community of love, humans support each other to fulfil their individual absolute oughts, to become their true selves: "The most salient feature of the community of love is that persons support each other in their different vocations and help each other to become what they are" (Loidolt 2012: 14).Ultimately, Husserl (2014: 332) concludes that "I can be wholly happy if and only if humanity as a whole can be" (emphasis in original, as translated in Cavallaro, Heffernan, 2019: 371). Husserl's ideal of the ethical life represents a strong interdependency (requirement for so-called "universal coherence") between "I", others, and community they form. Husserl's interpretation of being part of the community proceeds somewhat further than the Stoics', especially, in seeking this strong interdependency between "I" and overall happiness of the community.

Awareness of Death
Interpretation of the role of death in shaping awareness of authentic existence as unfolded by Heidegger and Seneca, appears to be the most compatible concepts between the two philosophies.
Heidegger points out that death is essentially one's own: "No one can take the Other's dying away from him" (emphasis in original, Heidegger 2001:284), and by that underscores the individual nature of one's being-there. Heidegger argues that death is a constitutive part of life, there is no life without death. By that, he illuminates the temporality of beingthere and that death is "pre-eminently looming" in one's life.
Heidegger distinguishes everydayness attitudes towards death as downplaying (it "just happens") and denial: "One of these days one will die too, in the end; but right now it has nothing to do with us" (Heidegger 2001: 297). An authentic (existential-ontological) approach to death, on the other hand, recognizes "death's certaintythat it is possible at any moment" (emphasis in original, Heidegger, 2001, 302). "Anticipation" is an attitude required for authentic existence. Consequently, one becomes free in a sense that one does not seek anymore to evade death by downplaying or denial, instead one lives in certainty, and is able to tackle one's own. For example, "When, by anticipation, one becomes free for one's own death, one is liberated from one's lostness in those possibilities which may accidentally thrust themselves upon one" (emphasis in original, Heidegger 2001:308), that is, it is easier with this awareness of death to think clearly of what is important in one's life and make choices accordingly.
Seneca suggests that it is wrong to expect death only sometime in the future, because all the time one has already lived is lost for her. He uses a parable of a water-clock: "It is not the last drop that empties the water-clock, but all that which previously has flowed out; similarly, the final hour when we cease to exist does not of itself bring death; it merely of itself completes the death-process" (Seneca 2013: 70). As a result of the misleading thought that death is something which is yet to be faced, one spends life by doing things amiss, and being unreasonably afraid of death. Seneca discusses various scenarios to prove why it is unreasonable to be afraid of death that could serve very practical functions of aiding errant minds (like death is coming anyway -fair or not, it does not change anything).
The advice Seneca proposes is to reflect regularly on death in order to develop a decent expectation management and invokes freedom as a desirable result of not being afraid of death and have proper impressions about it. Freedom for Seneca, again, is not to be dependent upon unreasonable impressions which he calls not to be a slave: ""Think on death." In saying this, he bids us think on freedom. He who has learned to die has unlearned slavery; he is above any external power, or, at any rate, he is beyond it" (Seneca 2013: 75). Like Heidegger, Seneca associates certainty of death, temporality of life, as well as death's possibility at any time, with proper impressions about death.
The approach to death of both Seneca and Heidegger are undoubtedly converging, including the understanding of what benefits this awareness brings: it brings freedom. For Heidegger, it is in a form of being able to tackle one's own, while for Seneca -to spend life doing proper things (which is, of course, to mind one's own). These ideas are also time-tested and still worthwhile, as contemporary Stoics find them helpful and retainable.

Conclusions
A comparison of the understanding of the concept of authentic existence between Phenomenology and Stoicism allows us to argue that there are points of various degrees of affinity in all concepts analysed in the article. Comparative research of authentic existence and its supplementary concepts of personal renewal, seeking cosmologic framework for ethics, being part of community, and awareness of death, has demonstrated convergence of elements of authentic existence: living consciously, reflecting on one's own life, taking ownership of one's life, it affects everything one does, self-improvement is a constant process, a reassuring arrangement of the world is required to provide meaning to an ethical life, encouragement to be an active part of society, and the perception of death as illuminating the temporality of being. Of course, there are also substantial differences amongst both philosophies, and the ethics part of Phenomenology is not as coherent as Stoics'.
Looking ahead, the analysis displays how philosophies across millennia and different branches of philosophy can (and are) enriching each other by offering refreshing interpretations, and an elaboration of concepts. At points, these two philosophies have interesting dynamics between them. Gary Madison is wondering, "what a properly phenomenological ethics might be said to look like" (Madison 2009: 17). He suggests looking towards Stoicism for an answer, and argues that by combining these two, "The result is a phenomenology that is not only intellectually-transcendentally sound but also ethically-existentially relevant -<…> an indispensable guide for living an authentically human life, a life of freedom and happiness" (Madison 2009: 27). Although it would require additional research to prove this argument, Stoicism, indeed, goes a step further by offering practical exercises that could serve as an inspiration for those willing to take up a philosophical life (including one based in Phenomenology). Heidegger's concepts of authentic existence and awareness of death seem to be compatible for this purpose, as are Husserl's ideas of personal renewal. On the other hand, contemporary Stoics presumably are already contemplating on Husserl's approach of taking entire life as a point of reference (Becker's example) and could benefit further by exploring the framing of ethical life in the circumstances of an indifferent universe.