Can you step into the same river twice? A closer look at human identity

Can You Step Into the Same River Twice?

The ancient Greek philosopher Heraclitus was famous for saying that it is not possible to step twice into the same river or to come into contact twice with a mortal being in the same state. His belief reflects the fact that things are always changing. The river is always moving, and people change physically, mentally, locationally, and in numerous other ways as time moves forward.

The presence of change raises the question of whether a river is one and the same thing existing at different times, or a series of different rivers existing one after another.

You can ask the same question about people. Is a human being a single, whole entity existing at different times, or a series of different entities existing one after another? After all, humans change a lot from conception to the final stage of adulthood.

Unsurprisingly, there are philosophical debates on this matter. Philosophers argue about the identity of all kinds of material objects, humans included. Yet our focus at hand will be human beings. How people answer the above question – whether or not they are aware of philosophical concepts – may influence how they perceive unborn humans.

Let’s look at an example.

“Rudimentary Components”

Political commentator Nathan J. Robinson claims, “life does not begin at a single identifiable moment… but unfolds over time.” He says, “As the zygote develops into the blastocyst, then the embryo, then the fetus, it is slowly gaining the properties that make it recognizably a human rather than the rudimentary components that initiate the development of a human.” Robinson therefore believes that “over the course of the time between fertilization and birth a creature is steadily created.”

First, notice his statement that [human] life does not begin at a single identifiable moment. We do know human organisms begin at fertilization, as explained in numerous biology textbooks, which state that the starting point for human life is the formation of the one-celled zygote.

Secondly, notice in his statements words like “moment,” “unfolds,” “slowly,” “over the course of time” and “steadily.” It is clear that time is an important idea in the perspective he is expressing, a view called “gradualism” in the abortion debate. Robinson isolates various human developmental stages – zygote, blastocyst, embryo, and perhaps even some fetal stages – and then considers that they are not human but merely a collection of “rudimentary components.” In other words, they are just parts.

What theory of time does Robinson subscribe to, and does it logically lead to denying moral status to unborn humans?

Temporal Parts?

Have you ever thought how strange it is that, although you are one person, you exist at different times and places? We take this for granted, but thinking deeply about it reveals this as something strange, marvelous, or mysterious. In spite of the innumerable different spaces and moments I have existed in, I somehow remained a singular person – me. But how do human beings persist as themselves through time? 

The theory that aligns with most people’s common sense and intuition is “endurantism.” This simply means that someone is wholly present at different times and endures through time. This is the view that holds, for example, that you are the same “you” today as you were at age 3, age 13, etc.

“Perdurantism,” by contrast, holds that a person is never wholly present. Rather, only a temporary slice of a person is present at any given time. These temporary slices are called “temporal parts.” Each of one’s temporal parts is numerically different from all the others. This would mean that the you-ten-years-ago, the you-yesterday, the you-right-now, and the you-tomorrow are different temporal parts of you. You are the sum of all your temporal parts, but none of your temporal parts contain the whole you.

Does this sound abstract? If so, that’s because it is. Such ideas are part of the branch of philosophy called metaphysics, which attempts to understand the fundamental nature of reality outside of sense perception. Metaphysics regards realities we find ourselves participating in – such as existence, identity, change, cause and effect, and space and time – that seem mysterious, mind-boggling, or sometimes contradictory.

With that in mind, let’s talk more about the implications of endurantism and perdurantism.

Three- and Four-Dimensionalism

Perdurantism is also known as four-dimensionalism because it implies that we extend in four dimensions. That fourth dimension is time and allows for the existence of the temporal parts. Four-dimensionalism implies that a person is located only at the temporal (temporary) region.

In endurantism, by contrast, people are three-dimensional. Three-dimensionalism implies that a person is located at all regions that collectively make up the spacetime region covered during their existence. What exists at each time is the whole person.

One of the reasons philosophers hold to perdurantism is that they are trying to explain change. They say that if something changes, it cannot be identical to what it was before, so it must be a different entity. A typical philosophical response to this is that change is not really a problem because change creates qualitative difference, not numerical difference. In other words, I am not perfectly similar to who I was in the past, but I am still the same entity as before.

The Problem of Vagueness

Another reason philosophers hold to perdurantism is to explain what they call “vagueness,” which can seem to occur at the beginning and ending of existence. At the end of one’s life, the boundary between life and death may be blurred for a short time. And though, as stated above, human life has a clear beginning, the vagueness regarding when a human life becomes “recognizably a human” sparks debate about things like personhood and moral status. Advocates of perdurantism say vagueness can be solved by understanding that people have temporal parts – that the whole person does not exist at any given time.

Recall that for Robinson a preborn human that isn’t recognizably a human is just “rudimentary components.” A zygote, for example, would not in Robinson’s mind be the whole person but just a temporal part, or stage, of the organism, numerically different from its future stages. Robinson appears to certainly believe in a philosophy of time that holds to temporal parts.

He is not alone. Have you wondered why so many supporters of abortion do not identify a zygote, embryo, or even fetus with the child it will later become? Most of them are unwittingly subscribing to a philosophy of temporal parts. Because these temporal parts are non-thinking, they are not considered “persons” by those who take this view.

Now we must ask: does belief in temporal parts need to conclude in the denial of moral status to the unborn?

Philosopher David Hershenov argues that it does not.

The Interests of Mindless Embryos

If you want to embrace four-dimensionalism with its belief in temporal parts, this need not lend itself to denying the moral status of mindless embryos and fetuses, Hershenov claims. His reason is this: temporal parts (if you believe in them) are linked together in a purposeful way that is in the organism’s interest. Humans, among other living things, have a developmental “telos,” or purpose. Telos is the ancient Greek term for an end, fulfillment, completion, goal or aim. Inanimate objects do not have these interests and therefore do not have a telos, Hershenov points out.

Hershenov explains that there are biological life processes dispersed throughout each human organism that work for the survival, flourishing, and fulfillment of the organism’s innate developmental pattern. Mindless embryos are linked to future thinking stages by these processes, which Hershenov calls “interests.” Sure, their interests are not yet conscious. But their well-being, including their future mental life, can be harmed or benefited. He concludes that there is a moral duty not to deprive creatures, including fetuses, of the conscious goods that are in their nature to realize. As long as they “can have pleasures and pains into the future, we have some prudential reason to obtain the former and avoid the latter,” he says. Hershenov quotes Jim Stone’s argument that beings, including fetuses, have a prima facie duty to be allowed to realize the conscious goods inherent in their nature. 

The views of Hershenov and Stone seem in line with a definition of moral status published by Cambridge: “To have moral status, an individual must be vulnerable to harm or wrongdoing. More specifically, a being has moral status only if it is for that being’s sake that the being should not be harmed, disrespected, or treated in some other morally problematic fashion.”

For Hershenov, even those who endorse four-dimensionalism must recognize this natural unity that connects one temporal stage to another. As he explains,

Our temporal parts must be causally immanent to one another, individuated by the presence of life processes that serve the well-being of the later temporal parts.

David Hershenov

Metaphysical Personhood

Philosopher Kristina Artuković offers very similar reasons as Hershenov for why humans at any stage of development have moral status. She holds that members of our natural kind, including unborn humans, have metaphysical personhood, an ontological status related to capabilities like consciousness, reasoning, self-motivated activity, communication and self-awareness. From conception to the end of our lives, we exist in a human development process regarding these capabilities. Artuković explains that there are only three ways that humans relate to metaphysical personhood: by attainment, retainment, and restoration. In other words, humans are always either attaining, retaining, or restoring these capabilities. 

Zygotes, embryos, fetuses and infants, among other humans, are in the process of attainment, which is what Hershenov calls the innate developmental pattern, or telos, of humans. Because they are in the process of attainment, they necessarily have moral status. “As individual members of our species, they are always in an active, inherent, self-initiated and self-governed relation of attaining the capabilities we all share radically…” Artuković says.

It may be tempting to see preborn humans in the earliest stages as potentially human. But this is a mistake, according to Artuković. She says,

This active relation to personhood… is far from mere ‘potentiality.’ Attainment, retainment, and restoration are actual, not potential.

Kristina Artuković

She explains that killing prenatal humans is killing entities who are actively involved “in the finite and foreseeable process of attaining consciousness and reason.” 

Although an “ontological status” for human beings is a metaphysical claim, it is one founded on undeniable biological processes that characterize humans. 

Widely-Held Moral Intuitions?

Let’s circle back to Nathan J. Robinson, who believes that human life does not begin at a certain moment but unfolds over time. He believes his view “accords with widely-held moral intuitions.”

How widely held are they? Grief after miscarriages doesn’t support his view. Neither does a study in which women are quoted talking about children they almost aborted but were unable to because they were denied abortions. One woman said, through tears, “She is just everything to me,” speaking of her daughter she had once sought to abort. Another woman said, “It breaks my heart that I actually thought about [having an abortion].” Yet another called raising her child “the best experience of my life,” though she had sought in the past to abort this same child. 

These quotes are from The Turnaway Study (2020) by Diana Greene Foster – a study used by abortion advocates. The above quotes are one of the study’s unpopular findings. Another unpopular one is that 96% of women who gave birth after being denied abortions no longer wished they could have had an abortion by the time their child was five.

For each of these women quoted in The Turnaway Study, there wasn’t any question that the fetus she once sought to abort was the same child she now loves dearly. These women were not thinking about philosophies of time or temporal parts as they made their statements. Their common sense, intuition and feelings told them that abortion would have killed the child they now love so much. They understand the biological fact that their child is the same physical organism they once sought to abort.

I suggest that Robinson’s views, no matter how widespread, do not stem from “moral intuitions” but from a metaphysical theory of time as it relates to human identity – a theory he embraces for its abstract convenience even while denying biological realities about the beginning point and developmental pattern of human life, without which none of us would be here.

There are, of course, other philosophical views and questions about the nature of time. Philosophers debate about what time is or if it even exists; and whether only the present moment is real or whether the past and future are also real. Such discussions are unlikely to have real world issues at stake and, along with the views at hand, belong in the realm of metaphysics. It is important to keep in mind that, regardless of any metaphysical theory, it is a known biological reality that each human organism from conception until death includes life processes that are causally linked through time. These life processes are organized around the telos of a human being to support its interests and are, as Artuković points out, actual – not potential.

[Read more – A Primer on Fetal Personhood and Consciousness]

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