Review Reports

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

The manuscript presents an ambitious and intellectually stimulating commentary that attempts to unify birth–death cycles across living and non-living systems within a thermodynamic and informational framework. By drawing on a wide and diverse body of literature, the author brings together ideas from metabolic scaling, ontogeny, dissipative structures, and systems theory to develop the concept of dissipative life cycles (DLC). One of the strengths of the manuscript is precisely this effort to move beyond organism-centered life-cycle models and to invite readers to think more broadly about life, death, and persistence as emergent properties of energy dissipation, information regulation, and system-level organization. As a commentary, the manuscript succeeds in stimulating interdisciplinary reflection and in raising questions that cut across traditional disciplinary boundaries.

Given the contribution's conceptual and speculative nature, the manuscript does not follow the structure of an empirical research article, nor does it present formal methods or quantitative analyses. Accordingly, my comments focus on the clarity and internal coherence of the conceptual framework, the way key distinctions are introduced and developed, and the extent to which the conclusions are convincingly supported by the arguments and examples provided. From this perspective, the manuscript raises many interesting and worthwhile ideas, but several aspects would benefit from further refinement in order to improve focus, clarity, and accessibility for a broad scientific readership. My specific suggestions are outlined below.

The conceptual framework would benefit from greater precision, particularly regarding the use of biologically loaded terms such as “life cycle,” “birth,” “growth,” “death,” and “aging” when applied to non-living systems. It is not always clear whether these terms are intended metaphorically, as functional analogies, or as components of a general theoretical framework that transcends biological systems. Explicitly clarifying this distinction early in the text would strengthen the argument's conceptual coherence and reduce ambiguity for readers from different disciplinary backgrounds. In addition, the assertion that the question of why life cycles exist has been insufficiently addressed would be more convincing if the manuscript briefly acknowledged and situated itself relative to existing frameworks, such as the thermodynamics of open systems, dissipative structures, or complex systems theory, even if the author’s aim is to move beyond them. From a structural perspective, the opening section is dense and could be improved by more clearly separating the general motivation from the statement of objectives and guiding questions.

In Section “Why do life cycles exist?”, the proposed explanation linking finite lifetimes to spatial discreteness and opposing ordering and disordering processes is conceptually appealing, but it remains largely qualitative. The argument would benefit from a clearer articulation of the mechanisms by which these properties lead to inevitable collapse across different classes of natural systems, and from a more explicit indication of how broadly these mechanisms are intended to apply.

At an earlier point in the manuscript, possibly in the section where living and non-living systems are first contrasted, it may be useful to briefly acknowledge the long-standing debate in biology regarding how “life” is defined. Even a short paragraph noting that multiple definitions exist and that a substantial literature addresses this question would help frame later discussions of birth, death, and life cycles in living versus non-living systems. This clarification would be particularly valuable given that several parts of the manuscript hinge on distinctions between the living and the non-living, as well as on concepts of birth and death.

In the section on “Intrinsic and extrinsic properties of natural systems with life cycles,” the description of natural systems as discrete, resource-dependent, dissipative structures offers a potentially unifying framework, but several claims remain largely qualitative. In particular, the argument invoking “selection for persistence” would benefit from clearer conceptual grounding, especially when extended beyond biological systems to stars, planets, or other non-living structures. Clarifying whether this selection is meant as a generalized physical principle, an analogy to biological selection, or a metaphor would improve conceptual consistency. Similarly, the discussion of temperature ranges and entropy production, while intuitively plausible, would be strengthened by a more explicit connection to established physical or thermodynamic principles and by a clearer separation between illustrative examples and general causal claims. The biblical phrase “from dust to dust” used in this section is evocative, but it may momentarily shift the tone away from a strictly scientific register; clearly signaling it as a metaphor could help maintain stylistic consistency.

In Section 4, “How are natural systems with life cycles ‘born’?”, the distinction between de novo formation in non-living systems and self-replication in living systems is clearly articulated and conceptually useful. However, the section would benefit from greater focus and tighter argumentative control. Several claims, particularly those concerning the limited evolutionary potential of de novo–forming systems and the uniqueness of biological self-replication, are presented in a largely descriptive manner and would be strengthened by clearer criteria and more explicit causal reasoning. In addition, the extensive detail on reproductive modes and life-history strategies, while accurate and well referenced, may exceed what is necessary to support the central conceptual argument of the section.

The proposed similarities in growth, peak, and decline patterns across fires, stars, organisms, and large-scale systems are largely descriptive and would benefit from a clearer distinction between empirically established patterns and hypotheses that remain speculative. The suggestion that differences between living and non-living systems arise primarily from homeostatic regulation is plausible, but it is currently underdeveloped and would benefit from further elaboration or clarification.

In the discussion devoted to how natural systems “age,” the comparison between living and non-living systems is intuitively appealing, but it would benefit from a clearer distinction between descriptive analogies and shared underlying mechanisms. While declines in size, energy intensity, and structural organization are convincingly illustrated across different systems, it remains unclear whether “aging” is intended as a unifying physical process or as a concept extended metaphorically from biology.

In the latter part of the discussion on ageing, the detailed treatment of life-history strategies, reproductive schedules, and within-organism heterogeneity highlights the biological richness of the topic, but it also increases the conceptual density of the section. Several important claims, such as antagonism between growth and senescence, the role of reproductive mode in shaping ageing rates, and the notion of “weakest-link” failure, are introduced in close succession and would benefit from clearer signposting and synthesis. Explicitly distinguishing well-supported empirical patterns from hypotheses that remain contested, and more clearly linking these biological insights back to the broader framework of ageing in natural systems, would improve clarity and maintain focus.

The section titled “Cycles within cycles” presents a rich and wide-ranging discussion of nested and hierarchical cycles, particularly in living systems, but its length and conceptual density risk obscuring the central message. Multiple levels of cyclicity, including whole-organism, molecular, cellular, population, ecosystem, and evolutionary cycles, are treated in rapid succession, often with limited synthesis between them. The section would benefit from clearer internal structuring, explicit signposting of its main conceptual claims, and more frequent summaries that distinguish core arguments from illustrative examples. As currently written, the abundance of detail may overwhelm readers and make it difficult to discern which relationships between cycles are empirically established, which are plausible analogies, and which remain open questions. In addition, several biologically specific discussions, such as those on sleep, dormancy, metabolic cycles, cell turnover, and speciation–extinction dynamics, would be strengthened by more explicitly tying them back to the overarching question of how nested cycles relate to life cycles as a general phenomenon.

In the section addressing the interrelatedness of cycles among natural systems, the range of examples effectively conveys the pervasiveness of cyclic coupling across physical, biological, and ecological scales. This section could be further strengthened by briefly highlighting a common conceptual thread or organizing principle that links these interactions, thereby helping the reader more clearly integrate the examples into the broader framework of the manuscript.

In the section examining the relationship between the temporal duration and structural size of natural systems with limited lifespans, the cross-system comparison is intellectually stimulating and clearly illustrates that size–lifetime scaling is not governed by a single universal rule. The argument would benefit from a more explicit synthesis clarifying which underlying factors, such as energetic throughput, environmental hazards, or system-specific constraints, are most relevant in each case. This would help readers better understand why contrasting scaling patterns emerge across different types of natural systems.

In the section devoted to a unifying theory of life cycles, the breadth of ideas and the ambition of the synthesis are clear strengths, but it is unusually long and conceptually dense. The argument would likely gain clarity and impact if it were streamlined, with a tighter focus on the core elements of the proposed framework and a more selective use of examples. Condensing some of the more speculative or repetitive passages, particularly those that revisit earlier sections or extend into philosophical territory, could improve readability and help the central theoretical contributions stand out more clearly.

In the concluding section, the manuscript effectively reiterates its central themes and the broad significance of the proposed framework. The conclusions could be strengthened by being slightly more concise and by more clearly distinguishing between established insights and more speculative implications, especially those that extend into philosophical or applied domains. This refinement would help sharpen the take-home messages for a broad scientific audience.

Overall, this commentary is intellectually rich, ambitious, and conceptually stimulating, offering an unusually broad and integrative perspective on birth–death cycles across natural systems. However, for a commentary article, the manuscript is extremely long and dense in places, often approaching the scope and depth of a full review or theoretical treatise. A more concise presentation, achieved by selectively condensing some sections, would likely improve readability, accessibility, and impact while preserving the originality and value of the core ideas. 

Author Response

Comment 1: The manuscript presents an ambitious and intellectually stimulating commentary that attempts to unify birth–death cycles across living and non-living systems within a thermodynamic and informational framework. By drawing on a wide and diverse body of literature, the author brings together ideas from metabolic scaling, ontogeny, dissipative structures, and systems theory to develop the concept of dissipative life cycles (DLC). One of the strengths of the manuscript is precisely this effort to move beyond organism-centered life-cycle models and to invite readers to think more broadly about life, death, and persistence as emergent properties of energy dissipation, information regulation, and system-level organization. As a commentary, the manuscript succeeds in stimulating interdisciplinary reflection and in raising questions that cut across traditional disciplinary boundaries.

Response 1: Thank you for your positive assessment.

Comment 2: Given the contribution's conceptual and speculative nature, the manuscript does not follow the structure of an empirical research article, nor does it present formal methods or quantitative analyses. Accordingly, my comments focus on the clarity and internal coherence of the conceptual framework, the way key distinctions are introduced and developed, and the extent to which the conclusions are convincingly supported by the arguments and examples provided. From this perspective, the manuscript raises many interesting and worthwhile ideas, but several aspects would benefit from further refinement in order to improve focus, clarity, and accessibility for a broad scientific readership. My specific suggestions are outlined below.

Response 2: Thank you for your thought-provoking comments, which have helped me to clarify many parts of my manuscript.

Comment 3: The conceptual framework would benefit from greater precision, particularly regarding the use of biologically loaded terms such as “life cycle,” “birth,” “growth,” “death,” and “aging” when applied to non-living systems. It is not always clear whether these terms are intended metaphorically, as functional analogies, or as components of a general theoretical framework that transcends biological systems. Explicitly clarifying this distinction early in the text would strengthen the argument's conceptual coherence and reduce ambiguity for readers from different disciplinary backgrounds. In addition, the assertion that the question of why life cycles exist has been insufficiently addressed would be more convincing if the manuscript briefly acknowledged and situated itself relative to existing frameworks, such as the thermodynamics of open systems, dissipative structures, or complex systems theory, even if the author’s aim is to move beyond them. From a structural perspective, the opening section is dense and could be improved by more clearly separating the general motivation from the statement of objectives and guiding questions.

Response 3: I have expanded the Introduction to clarify the motivation of my review and how I (and many others) use the term “life cycle” (and other related terms) metaphorically for a variety of living and non-living systems.  I only briefly mention theoretical frameworks based on thermodynamic dissipative structures because they are an integral part of Section 3.  

Comment 4: In Section “Why do life cycles exist?”, the proposed explanation linking finite lifetimes to spatial discreteness and opposing ordering and disordering processes is conceptually appealing, but it remains largely qualitative. The argument would benefit from a clearer articulation of the mechanisms by which these properties lead to inevitable collapse across different classes of natural systems, and from a more explicit indication of how broadly these mechanisms are intended to apply.

Response 4: Please be aware that Section 2 is meant to be a preface for later sections (including Sections 3, 6, 7 and 8 where more details are described.  

Comment 5: At an earlier point in the manuscript, possibly in the section where living and non-living systems are first contrasted, it may be useful to briefly acknowledge the long-standing debate in biology regarding how “life” is defined. Even a short paragraph noting that multiple definitions exist and that a substantial literature addresses this question would help frame later discussions of birth, death, and life cycles in living versus non-living systems. This clarification would be particularly valuable given that several parts of the manuscript hinge on distinctions between the living and the non-living, as well as on concepts of birth and death.

Response 5: I appreciate this comment, but I wish to avoid discussing the extensive and largely philosophical literature on how life is defined per se, as I note in my revised Section 1.  Doing so would make my review too long and complex and interrupt its logical flow.

Comment 6: In the section on “Intrinsic and extrinsic properties of natural systems with life cycles,” the description of natural systems as discrete, resource-dependent, dissipative structures offers a potentially unifying framework, but several claims remain largely qualitative. In particular, the argument invoking “selection for persistence” would benefit from clearer conceptual grounding, especially when extended beyond biological systems to stars, planets, or other non-living structures. Clarifying whether this selection is meant as a generalized physical principle, an analogy to biological selection, or a metaphor would improve conceptual consistency. Similarly, the discussion of temperature ranges and entropy production, while intuitively plausible, would be strengthened by a more explicit connection to established physical or thermodynamic principles and by a clearer separation between illustrative examples and general causal claims. The biblical phrase “from dust to dust” used in this section is evocative, but it may momentarily shift the tone away from a strictly scientific register; clearly signaling it as a metaphor could help maintain stylistic consistency.

Response 6: More explanation is now given regarding the “selection for persistence” (also see section 4), the metaphorical nature of the phrase “from dust to dust”, and the effect of temperature on the formation of dissipative structures.

Comment 7: In Section 4, “How are natural systems with life cycles ‘born’?”, the distinction between de novo formation in non-living systems and self-replication in living systems is clearly articulated and conceptually useful. However, the section would benefit from greater focus and tighter argumentative control. Several claims, particularly those concerning the limited evolutionary potential of de novo–forming systems and the uniqueness of biological self-replication, are presented in a largely descriptive manner and would be strengthened by clearer criteria and more explicit causal reasoning. In addition, the extensive detail on reproductive modes and life-history strategies, while accurate and well referenced, may exceed what is necessary to support the central conceptual argument of the section.

Response 7: I do not know how to improve the clarity of this section.  It already seems obvious to me and further explanation of why the life cycles of living systems are more diverse than those of non-living systems is given in Section 11.  This short section also provides only a little detail (not extensive detail as claimed by the reviewer) about the enormous diversity of the life cycles of living systems (which takes whole books to adequately describe), so that readers can appreciate this diversity, at least in part.  If I omitted this short discussion, uninformed readers would have no idea about the extensiveness of the diversity of which I speak. 

Comment 8: The proposed similarities in growth, peak, and decline patterns across fires, stars, organisms, and large-scale systems are largely descriptive and would benefit from a clearer distinction between empirically established patterns and hypotheses that remain speculative. The suggestion that differences between living and non-living systems arise primarily from homeostatic regulation is plausible, but it is currently underdeveloped and would benefit from further elaboration or clarification.

Response 8: This section is intended to be primarily descriptive because here I document with real examples how various natural systems (living and non-living) show changes in size and energy use during their life cycles.  Explanatory hypotheses are also clearly identified and proposed to stimulate further research, including phrases such as “I suggest” and “requiring testing”.

Comment 9: In the discussion devoted to how natural systems “age,” the comparison between living and non-living systems is intuitively appealing, but it would benefit from a clearer distinction between descriptive analogies and shared underlying mechanisms. While declines in size, energy intensity, and structural organization are convincingly illustrated across different systems, it remains unclear whether “aging” is intended as a unifying physical process or as a concept extended metaphorically from biology.

Response 9: In the Introduction, I have now explicitly stated that I apply terms such as “aging” (bracketed by quotation marks) to non-living systems as metaphors, as have many other physical scientists who have described the last stages of the life cycles of stars, tornadoes, etc. as “aging” or “dying”. 

Comment 10: In the latter part of the discussion on ageing, the detailed treatment of life-history strategies, reproductive schedules, and within-organism heterogeneity highlights the biological richness of the topic, but it also increases the conceptual density of the section. Several important claims, such as antagonism between growth and senescence, the role of reproductive mode in shaping ageing rates, and the notion of “weakest-link” failure, are introduced in close succession and would benefit from clearer signposting and synthesis. Explicitly distinguishing well-supported empirical patterns from hypotheses that remain contested, and more clearly linking these biological insights back to the broader framework of ageing in natural systems, would improve clarity and maintain focus.

Response 10: This section is meant to give readers a glimpse of the many patterns and mechanisms underlying “aging”, especially in living systems.  To do more would go beyond the scope of my review.  In addition, I have clearly identified hypotheses “requiring testing” in this section and elsewhere. 

Comment 11: The section titled “Cycles within cycles” presents a rich and wide-ranging discussion of nested and hierarchical cycles, particularly in living systems, but its length and conceptual density risk obscuring the central message. Multiple levels of cyclicity, including whole-organism, molecular, cellular, population, ecosystem, and evolutionary cycles, are treated in rapid succession, often with limited synthesis between them. The section would benefit from clearer internal structuring, explicit signposting of its main conceptual claims, and more frequent summaries that distinguish core arguments from illustrative examples. As currently written, the abundance of detail may overwhelm readers and make it difficult to discern which relationships between cycles are empirically established, which are plausible analogies, and which remain open questions. In addition, several biologically specific discussions, such as those on sleep, dormancy, metabolic cycles, cell turnover, and speciation–extinction dynamics, would be strengthened by more explicitly tying them back to the overarching question of how nested cycles relate to life cycles as a general phenomenon.

Response 11: In the introduction to Section 7, I outline the various kinds of nested cycles and my later discussions (separated in topical subsections, which can be considered “signposting”) on how they may affect life cycles.  In my introduction to Section 7, I also make clear that my discussion is exploratory, stating that “I hope to stimulate further research”.  Within subsections I also organize material according to specified questions.  In addition, I clearly state what has been observed versus what has been suggested.

Comment 12: In the section addressing the interrelatedness of cycles among natural systems, the range of examples effectively conveys the pervasiveness of cyclic coupling across physical, biological, and ecological scales. This section could be further strengthened by briefly highlighting a common conceptual thread or organizing principle that links these interactions, thereby helping the reader more clearly integrate the examples into the broader framework of the manuscript.

Response 12: I summarize this short section by saying “Cyclic behavior is not only pervasive in the universe but also interconnected in significant ways, especially on Earth. Therefore, attempting to understand birth and death in the universe requires an understanding of both the inner workings of natural systems and how they affect each other. Many cycles, including life cycles, depend on other cycles.”  Also see Section 12.

Comment 13: In the section examining the relationship between the temporal duration and structural size of natural systems with limited lifespans, the cross-system comparison is intellectually stimulating and clearly illustrates that size–lifetime scaling is not governed by a single universal rule. The argument would benefit from a more explicit synthesis clarifying which underlying factors, such as energetic throughput, environmental hazards, or system-specific constraints, are most relevant in each case. This would help readers better understand why contrasting scaling patterns emerge across different types of natural systems.

Response 13: The second paragraph of Section 9 already discusses how “underlying factors, such as energetic throughput” affect relationships between system size and duration.  Here I make clear that different mechanisms may apply to different systems, but no conclusive answer can yet be given, thus requiring further research.

Comment 14: In the section devoted to a unifying theory of life cycles, the breadth of ideas and the ambition of the synthesis are clear strengths, but it is unusually long and conceptually dense. The argument would likely gain clarity and impact if it were streamlined, with a tighter focus on the core elements of the proposed framework and a more selective use of examples. Condensing some of the more speculative or repetitive passages, particularly those that revisit earlier sections or extend into philosophical territory, could improve readability and help the central theoretical contributions stand out more clearly.

Response 14: Figure 8 provides a synthetic view of life cycles, thus bringing out the most important features of my suggested unifying view, which is a work in progress.  Only the highlights are emphasized in the text and thus I do not see why the reviewer regards this section as “unusually long”.  Although not mentioned by the reviewer, much of this section is also concerned with important questions for future research. 

Comment 15: In the concluding section, the manuscript effectively reiterates its central themes and the broad significance of the proposed framework. The conclusions could be strengthened by being slightly more concise and by more clearly distinguishing between established insights and more speculative implications, especially those that extend into philosophical or applied domains. This refinement would help sharpen the take-home messages for a broad scientific audience.

Response 15: Throughout my article I clearly distinguish hypotheses from established findings.

Comment 16: Overall, this commentary is intellectually rich, ambitious, and conceptually stimulating, offering an unusually broad and integrative perspective on birth–death cycles across natural systems. However, for a commentary article, the manuscript is extremely long and dense in places, often approaching the scope and depth of a full review or theoretical treatise. A more concise presentation, achieved by selectively condensing some sections, would likely improve readability, accessibility, and impact while preserving the originality and value of the core ideas. 

Response 16: I have re-categorized my article as a review, as recommended by the editors.  Given that my article (including tables and figures, but minus references) is 23 pages, I do not believe that it is too long for a review. 

Reviewer 2 Report

Comments and Suggestions for Authors

This paper takes an extremely broad scale view of processes of life and death. It links living organisms with non-living things like stars and tornadoes that arguably have births and deaths. It covers several issues that are important in different fields and it appears to give reasonable references to these as far as I can tell, but my feeling is that it does not add much to our understanding of any of these things. Trying to link them all together is almost a hopeless task because the similarities at this broad scale are necessarily very superficial. Cells, stars and tornadoes do not work in the same way. If we want to understand these things we need to concentrate on one thing at a time. I am not sure that this paper really helps.

For example, Fig 1 makes an important distinction between living organisms that reproduce and diversify, and non-living systems that do not. Hence living systems can evolve and non-living ones cannot, as is explained. I usually think of this from the point of view of how to define life in such a way as to exclude stars and tornadoes. Here it is presented from a different point of view. But the point is certainly well-recognized in the field of origins of life. So does this section contribute anything new? Not much, I think, because the question of definitions of life is already covered extensively in the literature.

Figs 2 and 3 discuss reproductive life cycles of living organisms. This is central to biology, with a big literature. But don’t biologists already appreciate that evolution can select for organisms with very different life cycles? What is new here?

Aging is also discussed. This is again a big field in biology. But what is new here? The questions of what are the limiting processes for molecular repair and maintenance of living organisms, which kinds of molecular damage are crucial for aging, and why some organisms age faster than others are important. But this has nothing much to do with the lifetimes of stars of different sizes.

From my own background, I know quite a lot about biology and origins of life, a certain amount about stars and hardly anything about tornadoes. The sections on stars and tornadoes appear OK, but I am guessing they are not state of the art for experts in those fields. If I really wanted to learn about tornadoes, would this paper help? I fear that it would not, and I would have to look at specific literature about tornadoes and weather.

Also, I am uncomfortable with terms like ‘life cycle’, ‘death’ and ‘immortality’ when applied to things which are not alive. Using these terms for stars and tornadoes seems to deliberately obscure the distinction between life and non-life.

At the end of the paper, it is claimed that there is a general unifying theory of all this. If that is true, it needs to be spelled out more clearly. Would it be possible to get to the point of the article much more quickly and to emphasize what is new about this theory (if anything)? At the moment the paper is a very long read and not very convincing.

Author Response

Comment 1: This paper takes an extremely broad scale view of processes of life and death. It links living organisms with non-living things like stars and tornadoes that arguably have births and deaths. It covers several issues that are important in different fields and it appears to give reasonable references to these as far as I can tell, but my feeling is that it does not add much to our understanding of any of these things. Trying to link them all together is almost a hopeless task because the similarities at this broad scale are necessarily very superficial. Cells, stars and tornadoes do not work in the same way. If we want to understand these things we need to concentrate on one thing at a time. I am not sure that this paper really helps.

Response 1: The reviewer is correct in saying that my review deals with many kinds of living and non-living systems.  However, he(she) believes that they are so different that comparing them is “a hopeless task”.  In response, let me say that I am in no way claiming that these systems entirely “work in the same way”, as made clear in my revised Introduction (and in section 11).  I compare both their similarities and differences, and my preliminary unifying view is explicitly multi-mechanistic and thus embraces various mechanisms that apply to different systems.  However, all life cycles do appear to involve dissipative structures, energy/matter gradients, and have similar energetic ontogenies of growth and demise, as I describe.  Seeking unifying perspectives is an important part of science, which is hindered by focusing on only one system at a time.      

Comment 2: For example, Fig 1 makes an important distinction between living organisms that reproduce and diversify, and non-living systems that do not. Hence living systems can evolve and non-living ones cannot, as is explained. I usually think of this from the point of view of how to define life in such a way as to exclude stars and tornadoes. Here it is presented from a different point of view. But the point is certainly well-recognized in the field of origins of life. So does this section contribute anything new? Not much, I think, because the question of definitions of life is already covered extensively in the literature.

Response 2: As I have clarified in my revised Introduction, my review is not meant to discuss the origin of the first life forms or definitions of life, which are huge and complex topics, but rather to talk about why “life cycles” exist in both living and non-living systems and how they are similar, as well as different.  Fig. 1 presents merely one aspect of my comparative analysis.

Comment 3: Figs 2 and 3 discuss reproductive life cycles of living organisms. This is central to biology, with a big literature. But don’t biologists already appreciate that evolution can select for organisms with very different life cycles? What is new here?

Response 3: As I have stated in my revised Introduction: “the most novel aspects of my review involve comparing the life cycles of various living and non-living systems, as an essential preliminary step toward deriving a unifying, multi-mechanistic theory of life cycles. Specialists who find my presentation of what we know about specific systems as not being new, or even incomplete, should keep my overall objective in mind. Even if some readers feel that I have not accomplished my challenging goal of developing a novel unifying perspective, I hope that they will be sufficiently stimulated by my comparative analyses in ways that will generate new research ideas/perspectives about the systems that most interest them. Nature is unaware of human-made scientific disciplines, and therefore, to understand nature we should not be afraid to employ a transdisciplinary perspective. Looking outside one’s specific discipline may provide new insights.” Figs. 2 and 3 are presented to support the above objective (showing how life cycles of living systems are relatively diverse compared to those of non-living systems).   

Comment 4: Aging is also discussed. This is again a big field in biology. But what is new here? The questions of what are the limiting processes for molecular repair and maintenance of living organisms, which kinds of molecular damage are crucial for aging, and why some organisms age faster than others are important. But this has nothing much to do with the lifetimes of stars of different sizes.

Response 4: Please read my response to the reviewer’s previous comment and my revised Introduction for perspective.  If the reviewer is correct that stars, tornadoes and organisms have nothing in common, then how does one explain why they all have finite life cycles involving increases and decreases in size and energy use, coupled with the ever-present effects of entropy production.  All these systems and their life cycles are part of the physical world and subject to its laws and thus must have something in common. 

Comment 5: From my own background, I know quite a lot about biology and origins of life, a certain amount about stars and hardly anything about tornadoes. The sections on stars and tornadoes appear OK, but I am guessing they are not state of the art for experts in those fields. If I really wanted to learn about tornadoes, would this paper help? I fear that it would not, and I would have to look at specific literature about tornadoes and weather.

Response 5: The major purpose of my review is not to provide new information about each type of natural system itself but rather to use what we know to compare their life cycles to see how they are similar or different and why.  See my revised Introduction for more perspective.

Comment 6: Also, I am uncomfortable with terms like ‘life cycle’, ‘death’ and ‘immortality’ when applied to things which are not alive. Using these terms for stars and tornadoes seems to deliberately obscure the distinction between life and non-life.

Response 6: I use these terms metaphorically (as do many physical scientists who have studied the “life cycles” of stars, tornadoes, lakes, etc.), as I now clearly state in my revised Introduction. 

Comment 7: At the end of the paper, it is claimed that there is a general unifying theory of all this. If that is true, it needs to be spelled out more clearly. Would it be possible to get to the point of the article much more quickly and to emphasize what is new about this theory (if anything)? At the moment the paper is a very long read and not very convincing.

Response 7: A preliminary unifying perspective is spelled out clearly in Figure 8.  Before this view can be presented, a comparative analysis of the various characteristics of the life cycles of living and non-living systems must be presented, which makes up a large part of my review.  It is not only an essential means to an end, but I feel that the journey itself is worthwhile if one is not a priori skeptical about its usefulness.  If the life cycles of various natural systems have nothing in common, then why do many physical scientists use the terms “life cycles”, “birth”, “aging” and “death” to refer to the temporal existence and dynamics of many non-living systems in a way that is analogous to how these terms are used for living systems?  My analysis is meant to stimulate further research on life cycles in general, not to provide a definitive picture, which is “a work in progress”, as I state.

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

Thank you for your thorough responses and the thoughtful revisions. The expansions in the Introduction clarifying the metaphorical use of terms like "life cycle," "birth," and "aging," along with the added details on "selection for persistence," temperature effects, and exploratory framing in Sections 7 and 9, successfully address the main concerns. Figure 8 provides an excellent synthesis, and the overall distinctions between established findings and hypotheses are now even clearer. These changes greatly improve conceptual coherence, focus, and accessibility.

Reviewer 2 Report

Comments and Suggestions for Authors

The author has responded well to the previous comments. I think the article gives a novel point of view and the author should be allowed to present this. I am still not fully convinced that bringing this wide range of subjects together helps very much, but I am willing to support publication.