Actualism
Encyclopedia
In contemporary analytic philosophy
, actualism is a position on the ontological status
of possible world
s that holds that everything that exists (i.e., everything there is) is actual. Another phrasing of the thesis is that the domain
of unrestricted quantification ranges over all and only actual existents.
The denial of actualism is possibilism
, the thesis that there are some entities that are merely possible: these entities exist (in the same way that ordinary objects around us do) but are not to be found in the actual world. Regarding Modal realism
: “An important but significantly different notion of possibilism to which many of the issues in this article do not apply was developed by the philosopher David Lewis
.”
exists." This is a false statement about the world, but is usually accepted as representing a possible truth. This contingency is usually described by the statement "there is a possible world in which Sherlock Holmes exists". The possibilist argues that apparent existential claims such as this (that "there are" possible worlds of various sorts) ought to be taken more or less at face value: as stating the existence of two or more worlds, only one of which (at the most) can be the actual one. Hence, they argue, there are innumerably many possible worlds other than our own, which exist just as much as ours does.
Most actualists will be happy to grant the interpretation of "Sherlock Holmes' existence is possible" in terms of possible worlds. But they argue that the possibilist goes wrong in taking this as a sign that there exist other worlds that are just like ours, except for the fact that we are not actually in them. The actualist argues, instead, that when we claim "possible worlds" exist we are making claims that things exist in our own actual world which can serve as possible worlds for the interpretation of modal claims: that many ways the world could be (actually) exist, but not that any worlds which are those ways exist other than the actual world around us.
are nothing more than fictions created within the actual world. Possible worlds are mere descriptions of ways this world (the actual one) might have been, and nothing else. Thus, as modal constructions, they come in as a handy heuristic device to use with modal logic; as it helps our modal reasoning to imagine ways the world might have been. Thus, the actualist interpretation of "◊p" sees the modality (i.e. "the way" in which it is true) as being de dicto
and not entailing any ontological commitment
.
So, from this point of view, what distinguishes the actual world from other possible worlds is what distinguishes reality from a description of a simulation of reality, this world from Sherlock Holmes’: the former exists and is not a product of imagination and the latter does not exist and is a product of the imagination set in a modal construction.
From a modal realist’s point of view, such as Lewis’
, the proposition "◊p" means that p obtains in at least one other, distinct world that is as real as the one we are in. If a state of affairs is possible, then it really obtains, it physically occurs in at least one world. Therefore, as Lewis is happy to admit, there is a world where someone named Sherlock Holmes lived at 221b Baker Street in Victorian times, there is another world where pigs fly, and there is even another world where both Sherlock Holmes exists and pigs fly.
This leaves open the question, of course, of what an actually existing "way the world could be" is; and on this question actualists are divided. One of the most popular solutions is to claim, as William Lycan
and Robert Adams do, that "possible worlds" talk can be reduced to logical relations amongst consistent and maximally complete sets of propositions. "Consistent" here means that none of its propositions contradict one another (if they did, it would not be a possible description of the world); "maximally complete" means that the set covers every feature of the world. (More precisely: a set of propositions is "maximally complete" if, for any meaningful proposition P, P is either an element of the set, or the negation of an element of the set, or entailed by the conjunction of one or more elements of the set, or the negation of a proposition entailed by the conjunction of one or more elements of the set). Here the "possible world" which is said to be actual is actual in virtue of all its elements being true of the world around us.
Another common actualist account, advanced in different forms by Alvin Plantinga
and David Armstrong
views "possible worlds" not as descriptions of how the world might be (through a very large set of statements) but rather as a maximally complete state of affairs
that covers every state of affairs which might obtain or not obtain. Here, the "possible world" which is said to be actual is actual in virtue of that state of affairs obtaining in the world around us. (Since it is maximally complete, only one such state of affairs could actually obtain; all the others would differ from the actual world in various large or small ways.)
Analytic philosophy
Analytic philosophy is a generic term for a style of philosophy that came to dominate English-speaking countries in the 20th century...
, actualism is a position on the ontological status
Ontology
Ontology is the philosophical study of the nature of being, existence or reality as such, as well as the basic categories of being and their relations...
of possible world
Possible world
In philosophy and logic, the concept of a possible world is used to express modal claims. The concept of possible worlds is common in contemporary philosophical discourse and has also been disputed.- Possibility, necessity, and contingency :...
s that holds that everything that exists (i.e., everything there is) is actual. Another phrasing of the thesis is that the domain
Domain of discourse
In the formal sciences, the domain of discourse, also called the universe of discourse , is the set of entities over which certain variables of interest in some formal treatment may range...
of unrestricted quantification ranges over all and only actual existents.
The denial of actualism is possibilism
Possibilism
Possibilism may refer to:* Possibilism , a theory of cultural geography* Possibilism , a 1880s faction of the Federation of the Socialist Workers of France...
, the thesis that there are some entities that are merely possible: these entities exist (in the same way that ordinary objects around us do) but are not to be found in the actual world. Regarding Modal realism
Modal realism
Modal realism is the view, notably propounded by David Kellogg Lewis, that all possible worlds are as real as the actual world. It is based on the following tenets: possible worlds exist; possible worlds are not different in kind from the actual world; possible worlds are irreducible entities; the...
: “An important but significantly different notion of possibilism to which many of the issues in this article do not apply was developed by the philosopher David Lewis
David Lewis
-Academics:*David Lewis , civil lawyer and first Principal of Jesus College, Oxford*David Lewis , English author and psychologist*David C...
.”
Example
Consider the statement "Sherlock HolmesSherlock Holmes
Sherlock Holmes is a fictional detective created by Scottish author and physician Sir Arthur Conan Doyle. The fantastic London-based "consulting detective", Holmes is famous for his astute logical reasoning, his ability to take almost any disguise, and his use of forensic science skills to solve...
exists." This is a false statement about the world, but is usually accepted as representing a possible truth. This contingency is usually described by the statement "there is a possible world in which Sherlock Holmes exists". The possibilist argues that apparent existential claims such as this (that "there are" possible worlds of various sorts) ought to be taken more or less at face value: as stating the existence of two or more worlds, only one of which (at the most) can be the actual one. Hence, they argue, there are innumerably many possible worlds other than our own, which exist just as much as ours does.
Most actualists will be happy to grant the interpretation of "Sherlock Holmes' existence is possible" in terms of possible worlds. But they argue that the possibilist goes wrong in taking this as a sign that there exist other worlds that are just like ours, except for the fact that we are not actually in them. The actualist argues, instead, that when we claim "possible worlds" exist we are making claims that things exist in our own actual world which can serve as possible worlds for the interpretation of modal claims: that many ways the world could be (actually) exist, but not that any worlds which are those ways exist other than the actual world around us.
Philosophical viewpoints
From an actualist point of view, such as Adams', possible worldsPossible Worlds
Possible Worlds may refer to:* Possible worlds, a concept in philosophy* Possible Worlds , by John Mighton** Possible Worlds , by Robert Lepage, based on the Mighton play* Possible Worlds , by Peter Porter...
are nothing more than fictions created within the actual world. Possible worlds are mere descriptions of ways this world (the actual one) might have been, and nothing else. Thus, as modal constructions, they come in as a handy heuristic device to use with modal logic; as it helps our modal reasoning to imagine ways the world might have been. Thus, the actualist interpretation of "◊p" sees the modality (i.e. "the way" in which it is true) as being de dicto
De dicto and de re
De dicto and de re are two phrases used to mark important distinctions in intensional statements, associated with the intensional operators in many such statements. The distinctions are most recognized in philosophy of language and metaphysics....
and not entailing any ontological commitment
Ontological commitment
In the philosophy of language and metaphysics, an ontological commitment is said to be necessary in order to make a proposition in which the existence of one thing is presupposed or implied by asserting the existence of another. We are “committed” to the existence of the second thing, even though...
.
So, from this point of view, what distinguishes the actual world from other possible worlds is what distinguishes reality from a description of a simulation of reality, this world from Sherlock Holmes’: the former exists and is not a product of imagination and the latter does not exist and is a product of the imagination set in a modal construction.
From a modal realist’s point of view, such as Lewis’
David Kellogg Lewis
David Kellogg Lewis was an American philosopher. Lewis taught briefly at UCLA and then at Princeton from 1970 until his death. He is also closely associated with Australia, whose philosophical community he visited almost annually for more than thirty years...
, the proposition "◊p" means that p obtains in at least one other, distinct world that is as real as the one we are in. If a state of affairs is possible, then it really obtains, it physically occurs in at least one world. Therefore, as Lewis is happy to admit, there is a world where someone named Sherlock Holmes lived at 221b Baker Street in Victorian times, there is another world where pigs fly, and there is even another world where both Sherlock Holmes exists and pigs fly.
This leaves open the question, of course, of what an actually existing "way the world could be" is; and on this question actualists are divided. One of the most popular solutions is to claim, as William Lycan
William Lycan
William G. Lycan is a noted American philosopher teaching at the University of North Carolina at Chapel Hill,where he is the William Rand Kenan, Jr. Distinguished Professor. He won the Class of 2001 Outstanding Faculty Award and a Distinguished Teaching Award for Post-Baccalaureate Instruction in...
and Robert Adams do, that "possible worlds" talk can be reduced to logical relations amongst consistent and maximally complete sets of propositions. "Consistent" here means that none of its propositions contradict one another (if they did, it would not be a possible description of the world); "maximally complete" means that the set covers every feature of the world. (More precisely: a set of propositions is "maximally complete" if, for any meaningful proposition P, P is either an element of the set, or the negation of an element of the set, or entailed by the conjunction of one or more elements of the set, or the negation of a proposition entailed by the conjunction of one or more elements of the set). Here the "possible world" which is said to be actual is actual in virtue of all its elements being true of the world around us.
Another common actualist account, advanced in different forms by Alvin Plantinga
Alvin Plantinga
Alvin Carl Plantinga is an American analytic philosopher and the emeritus John A. O'Brien Professor of Philosophy at the University of Notre Dame. He is known for his work in philosophy of religion, epistemology, metaphysics, and Christian apologetics...
and David Armstrong
David Malet Armstrong
David Malet Armstrong , often D. M. Armstrong, is an Australian philosopher. He is well-known for his work on metaphysics and the philosophy of mind, and for his defence of a factualist ontology, a functionalist theory of the mind, an externalist epistemology, and a necessitarian conception of the...
views "possible worlds" not as descriptions of how the world might be (through a very large set of statements) but rather as a maximally complete state of affairs
State of affairs
The state of affairs is that combination of circumstances applying within a society or group at a particular time. The current state of affairs may be considered acceptable by many observers, but not necessarily by all. The state of affairs may present a challenge, or be complicated, or contain a...
that covers every state of affairs which might obtain or not obtain. Here, the "possible world" which is said to be actual is actual in virtue of that state of affairs obtaining in the world around us. (Since it is maximally complete, only one such state of affairs could actually obtain; all the others would differ from the actual world in various large or small ways.)