Argumenty bioetyki 2012

wykład 6

KWESTIA POTENCJALNOŚCI

- A

konkluzja argumentu z

podzielności – trzy wersje

... wczesny ludzki zarodek (w niektórych lub

wszystkich przypadkach) nie jest jeszcze

indywidualnym organizmem ludzkim, dającym

się utożsamić z dojrzałym ludzkim osobnikiem.

A to dlatego, że

• A. w ogóle nie jest indywidualnym organizmem;
• B. nie jest indywidualnym organizmem ludzkim;
• C. nie daje się utożsamić z dojrzałym ludzkim

osobnikiem, gdyż nie łączy się jeszcze z żadną

indywidualną osobowością.

ad C - podzielność jako oznaka

braku niepowtarzalnej

osobowości

• [„the chance of twinning (...) makes

it impossible to say that at
fertilization there exists a unique
human being” (Steinbock, Life Before
Birth, p. 50)]

rozumienie potencjalności jako

prawdopodobieństwa

• “Once spermatozoon and ovum meet and the

conceptus is formed, such studies as have been made

show that roughly in only 20 percent of the cases will

spontaneous abortion occur. In other words the

chances are about 4 out of 5 that this new being will

develop. At this stage in the life of the being there is a

sharp shift in probabilities, an immense jump in

potentialities. . . .If a spermatozoon is destroyed, one

destroys a being which had a chance of far less than 1

in 200 million of developing into a reasoning being ...

If a fetus is destroyed, one destroys a being ... which

had an 80 percent chance of developing further into a

baby outside the womb who, in time, would reason”.

John T, Noonan, `An Almost Absolute Value in History',

in J. Feinberg (ed.), op. cit., p. 12 and p. 13.

• IVF has reduced the difference between what can be said

about the embryo and what can be said about the egg and

sperm, considered jointly. Before IVF, any normal human

embryo known to us had a far greater chance of becoming

a child than any egg and sperm prior to fertilization. But

with lVF, there is a much more modest difference in the

probability that a child will result from a two-cell embryo in

a glass dish and the probability that a child will result from

an egg and some sperm in a glass dish. To be specific, if we

assume that the laboratory's fer tilization rate is 80 percent

and its rate of pregnancy per embryo trans ferred is 10

percent, then the probability that a child will result from a

given embryo is 10 percent, and the probability that a child

will result from an egg which has been placed in a culture

medium to which sperm has been added is 8 percent.

(Singer & Dawson 1988, s. 90)

• if we compare the probability that the

embryo will become a person with the
probability that the egg, together with
the single sperm about to be
microinjected into the egg, will become
a person, we will be unable to find any
sharp distinction between the two. Even
the genetic blueprint will have been
determined in both cases. (s. 101)

Arystoteles, kwestia bytu

potencjalnego

• „Należy teraz wyjaśnić, kiedy coś jest

w możności [dynamei, potentia], a

kiedy nie. Bo nie jest kiedykolwiek.

Czy na przykład ziemia jest już

człowiekiem w możności? Nie. Będzie

bowiem dopiero wtedy, gdy stanie się

nasieniem, a prawdopodobnie i wtedy

jeszcze nie.” (Arystoteles, Metafizyka,

1049a)

Arystoteles, potencjalność

nasienia i potencjalność

zarodka

• Na przykład nasienie nie jest jeszcze człowiekiem w

możności (gdyż musi być umieszczone w kimś drugim i ulec

przemianie): dopiero gdy będzie takie na mocy zasady

wewnętrznej, wtedy będzie człowiekiem w możności, ale

najpierw potrzebne jest działanie jeszcze innego. Podobnie

ziemia nie jest od razu figurą w możności, gdyż dopiero w

wyniku przemiany stanie się ona brązem (Arystoteles,

Metafizyka, 1049a, tłum. T. Żeleźnika)

• The seed is not yet potentially a man; for it must be

deposited in something other than itself and undergo a

change. But when through its own motive principle it has

already got such and such attributes, in this state it is

already potentially a man; while in the former state it needs

another motive principle, just as earth is not yet potentially

a statue (for it must first change in order to become brass)

(Arystoteles, Metafizyka, 1049a)

Arystoteles, potencjalność

nasienia i potencjalność

zarodka

• nasienie przed przemianą (podlegające

zmianie wywołanej przez czynnik

zewnętrzny)
↓

• nasienie w trakcie przemiany

(zmieniające się na mocy zasady

wewnętrznej)
↓

• nasienie po przemianie (człowiek w

możności)

• Potential is active if the intrinsic

properties of an individual are the

primary causal factor in the realization of

its potential; potential is passive if the

primary causal determinate of change

comes from the outside, in causal factors

that are properly extrinsic to the

individual. Put another way, active

potential drives change from within;

passive potential is the consequence of

outside forces. (Brown 2007, s. 599)

• Unlike gametes (...), and unlike somatic cells

that might be used in cloning, human

embryos have within themselves not only all

[of] the organizational information needed

but also the active disposition to use that

information to develop themselves to the

stage of a mature human being. If provided a

suitable environment and nutrition, and

barring accident, disease, or intentional

violence done to them, these nascent human

beings will grow by an integrated, self-

directed process ... (Lee, George 2006)

dwa znaczenia

“potencjalności”

• Buckle 1988: potential to become –

potential to produce

• McMahan 2002: identity-preserving

potential – nonidentity potential