It was already suggested in the previous section, that every presentist who wants to speak seriously about past time should accept the existence of the flow of time and introduce it into her/his ontology. Kierland and Monton were close to the solution which is going to be proposed in this paper when they claimed that, for the presentist, the past is a fundamental aspect of reality (6) and that the past is what has happened: what things existed and how they were (7). Unfortunately, they also maintained that the past is brute and although the brute past is supposed to form a sui generis metaphysical category, an explanation of what the brute past is, according to the authors, unattainable:
The brute past has an intrinsic nature. Given what we say next, we like to think of this intrinsic nature in terms of the past having a certain ‘shape’. This shape does not consist in a structure of things having properties and standing in relations to one another. The past is an aspect of reality, even though no past things are. How can this be? There is no reductive explanatory answer to this question. The crucial feature of brute past presentism is that is postulates a sui generis metaphysical category, one independent of things and how they are. (Kierland and Monton 2007: 491)
Of course, any opponent of the idea of the introduction of the flow of time into the ontology of presentism can object: not so fast, wait a moment: have you perhaps explained what is the flow of time, or perhaps you are trying to explain ignotum per ignotius? S/he may also object that a simple admixture of the thesis about the flow of time to her/his main thesis (1/2) does not change the situation of the presentist too much because, according to the main ontological thesis of presentism, only the present exists and thus there will still be missing a plausible metaphysical category of the past on which the truth-value of past-tense claims can supervene.
I would answer such doubts by saying that a deeper change in the ontological position of the presentist is indeed necessary. This is a change which introduces real dynamics into this view and allows us to say what did exist, however, does not exist. I would also add that a plausible explanation of what constitutes the flow of time was offered by Broad (1938) in terms of the absolute becoming of events, that is, their coming to pass,Footnote 9 and that this approach can be developed in the dynamic and full-blooded versions of presentism which deserve to be called dynamic presentism (DP). Let us briefly introduce two such presentist solutions developed by means of the notion becoming after Gołosz (2013, 2017c), and by means of the notion of dynamic existence after Gołosz (2013, 2015, 2018).
So, let us start with the first approach and introduce this version of DP in the following form (expressed in tensed language):
Becoming: The events which our world consists of become (come to pass).
where becoming, as Broad’s absolute becoming, is a primitive notion which cannot be further analysed in terms of a non-temporal copula and some kind of temporal predicate.Footnote 10 This thesis expresses, of course, the reality of the flow of time, however, it is easy to show that Becoming also leads precisely to the ontological thesis of presentism.Footnote 11 To show this, we should only notice that Becoming says that events become, that is, they come into being and then they pass, and recall that, according to the long presentist tradition, the present can be identified with what exists.Footnote 12 It means exactly that only present events exist. This formulation of presentism, however, avoids the triviality objection because neither the notion of the present nor the notion of time are involved in Becoming.Footnote 13
Now, what remains is to introduce three definitions:
The present ≡ The totality of events which become (come to pass).
The past ≡ The totality of events which became (came to pass).
The future ≡ The totality of events which will become (will come to pass).
The first of these definitions was adopted following the above mentioned presentist tradition of identifying the present with what exists, the second and the third ones were assumed by analogy. Such a version of presentism has some virtues which speak for themselves:Footnote 14
According to Becoming, the present is continuously changing, which means that it allows the expression of a dynamic character of reality, which presentism in the form of a single thesis of the form (1, 2) is not able to do.
It avoids the question of the rate of time’s passage because—as emphasized by Broad—the notion of becoming is primitive and unrelated to anything else, and especially it is not related to time.
This formulation of presentism also avoids the triviality objection because the notion of the present is not involved in Becoming and thus this thesis is not trivial.
This version of presentism provides us with the metaphysical category of the past which we have sought.
From the point of view of this paper, the last virtue is especially important: this version of presentism provides us with the metaphysical category of the real past which we have sought: the past consists of the totality of events which became (came to pass). Thanks to this, it allows us to differentiate between actual events, such as, for example, the case of Socrates, which did become, and fictions such as the capture of Cerberus by Heracles, which did not become.
At this point, Kierland and Monton could oppose: Becoming cannot be treaed as a remedy for positions such as BPP because we rejected the ontology of facts and our ontology is based on things and the way they are; we emphasized that fact–talk is always parasitic on something which is metaphysically more fundamental.Footnote 15 And that is why we cannot accept such a solution to our Dilemma—they could add.
I would answer such an objection by claiming that the notion of becoming and the dynamic version of presentism presented can be further developed in such a way that things and the way they are would be included in ontology as fundamental objects. This is precisely the second version of presentism which was mentioned above and which is introduced in Gołosz (2013, 2015, 2018). It is based on the notion of the dynamic existence of things to emphasize a fundamental difference between things and events—while existence of both things and instantaneous events has a dynamic character, the former do not cease to be but persist by enduring, that is by keeping their strict (literal or numerical) identity over time:Footnote 16
Dynamic Reality: All of the objects that our world consists of exist dynamically.
where Dynamic Reality (DR) is expressed in the tensed language and the notion of dynamic existence is a primitive notion (just as Broad’s absolute becoming) which can be roughly characterised by the set of postulates:
the notion of dynamic existence is tensed;
things that dynamically exist endure;
events (which are acts of acquiring, losing or changing properties by dynamically existing things and their collections) dynamically exist in the sense of coming to pass.
The term “objects” is here used in such a way that it applies to things and events, however things are treated here as primary objects, while events are secondary.Footnote 17
DR is accompanied by the three definitions (similarly to Becoming):
The present ≡ The totality of objects that dynamically exist.
The past ≡ The totality of objects that dynamically existed.
The future ≡ The totality of objects that will dynamically exist.
Again, as in the case of Becoming, DR expresses at the same time the reality of the flow of time and the ontological thesis of presentism in the form of one single thesis. DR has the same virtues (i–iv) as Becoming (with swapping Becoming for DR, of course) and once again, from the point of view of this paper, the last virtue is especially important: this version of presentism also provides us with the metaphysical category of the real past which we need so much: the past consists of the totality of objects that dynamically existed.
DR, however, has two essential advantages not only over Becoming, but over every other version of presentism: first, the endurance of things is here a simple logical consequence of the dynamic existence of things, that is, it is a consequence of their way of existence proposed in this thesis. Contrary to what is commonly assumed by the presentists, the enduring of things is not a logical consequence of presentist theses of type (1/2) as shown by Brogaard.Footnote 18
The second advantage is even more important: the notion of dynamic existence which is applied in it is supposed to supersede the ordinary notion of existence which is standardly used by the presentists (and eternalists as well) and which has a static character, that is, it is a fixed existence in a fixed moment of time which is not appropriate for expressing the transitory character of the present. From this that I exist—in the tensed meaning of the standard term “exist”—in no way follows that I will not exist, neither that I am changing. Similarly—when we use tensed language—the standard notion of existence does not explain how it is possible and what it really means that the past existed and that the future will exist although both do not exist (in the tensed meaning of the term “exist”).
This is very important for two reasons: first, because it means that it makes no sense to ask whether things that dynamically existed do (statically) exist or do not (statically) exist: the notion of dynamic existence supersedes the notion of (static) existence and introduces more metaphysical categories than the latter. While the latter introduces only two fixed metaphysical categories of what exists and what does not exist, the former introduces six metaphysical categories which are continuously changing: the past (things and events that dynamically existed); the present (things and events that dynamically exist); the future (things and events that will dynamically exist); and their complements, that is, the past’ (things and events that did not dynamically exist); the present’ (things and events that does not dynamically exist); and the future’ (things and events that will not dynamically exist). So, for example, Socrates belongs to the past, while Zeus and Apollo belong to its complement, that is, the past’. They (Zeus and Apollo, of course) belong to the present’ and to the future’ as well. What should be emphasised, once again, is that all six categories are continuously changing, namely the past and the future’ are growing, the future and the past’ are shrinking, while the present—to say it meataphorically—is ‘moving’ toward the direction which we call the future (I would like to empahsize here that the term ‘move’ was not used in DR).
There is a second reason to be considered and which is mentioned above, namely that Kierland and Monton (2007: 492) complained about the lack of a metaphysically perspicuous language for describing the ‘shape of the past.’Footnote 19 The last version of dynamic presentism equipped with the notion of dynamic existence provides us with a language which allows us to talk not only about Kierland and Monton’s ‘shape of the past,’ but also about a structure of past things, their having properties and standing in relation to one another. Thus it allows us to say, for example, that Heraclitus (who dynamically existed) didn’t like Pythagoras (who dynamically existed), or that Heraclitus (who dynamically existed) was a native of the city of Ephesus (which dynamically existed). The language of DP also enables us to talk about the past, the present and the future, as they are changing, and to differentiate between objects like Socrates—on the one hand—that did dynamically exist, and Zeus and Apollo—on the other—that did not dynamically exist. What this means, and is of fundamental importance, is that, in this way, the notion of dynamic existence and DP provide presentists with a rationale for introducing and making use of tensed language:Footnote 20 this is exactly the dynamic existence of the world which is resposible for this that it is continuously changing, and that although Socrates (dynamically) existed, does not (dynamically) exist any more, and we should speak about him using the past tense. And, of course, the same concerns all other past objects.
At the end of this section, I would like to mention an additional bonus provided by DP concerning the problem of being-supervenience (or truthmaking). Namely, the presentists who try to respond to the objection from being-supervenience, usually assume that they need not look for an ontological basis for (contingent) future-tense claims because the claims about the future are not determined and lack truth-value.Footnote 21 But what is the origin of this asymmetry between the fixed past and (probably) open future? We cannot change the past no matter how strongly we would like to do this. But we have traces of it in our memory and in the world around us. Conversely, the future seems to be open—our experience seems to suggest this openness and quantum mechanics confirms this conviction—and perhaps it depends on our actions. How it is possible? Physics is silent on this issue; the physical laws describing the electrodynamic, strong and gravitational interactions are invariant under time reversal and as such cannot distinguish any direction of time. In turn, weak interactions are not time reversal invariant, but they are not involved in the processes leading to the coming into being of the traces of the past which we observe in everyday life.Footnote 22 Presentism in its standard form (1 or 2) is also silent on this issue: no ‘move’ of the present and no asymmetry of time follows from (1 or 2). DP in both versions provides us with a simple metaphysical solution to this exciting mystery: the past has already become or dynamically existed, as such is fixed and directly unavailable, we can only get to know it by its traces. Contrary to the past, which dynamically existed (or became) and as such is fixed and cannot be changed, the future looks as if it were open: it does not dynamically exist yet, it will only come into (dynamic) existence and, for this reason, we can probably influence it, at least sometimes.Footnote 23
It should also be emphasized that while brute past presentism can be accused of being an ad hoc solution to the objection from being-supervenience,Footnote 24DP cannot be: both versions of presentism, and the notions of becoming and dynamic existence which these versions of presentism are based on, were introduced as a solution to the difficulty with the explanation of what the flow of time consists in and the explanation of the ontological status of past, present and future objects is an additional bonus.