Phylogeny

H&M state that whenever animals update their current model they become oblivious to their earlier model of the world. This statement is rather perplexing, as if animals cannot recall previous states of the environment once it changes. When it comes to temporal behavior, humans and animals are basically on the same page. Not only is temporal behavior in animals characterized by the same laws of psychophysics, for example, scalar invariance (Buhusi & Meck Reference Buhusi and Meck2005; Wearden Reference Wearden2016), animals also extract more abstract, namely ordinal or even algebraic patterns, from sequences of events (Dehaene et al. Reference Dehaene, Meyniel, Wacongne, Wang and Pallier2015). This evidence reminds us not to underestimate their temporal abilities. However, it is not detrimental to H&M's major point that animals lack temporal reasoning, because on this level, time need not be represented explicitly.

Ontogeny

H&M describe a tripartite developmental sequence that children pass through: from (1) temporal updating (3 years) over (2) an intermediate phase where they roughly distinguish present from past and future (4 years) to (3) temporal reasoning about proximal and distal past and future events located at specific points on an extended temporal dimension. How might children extract such an abstract dimension from their temporal experience in the world? Representational redescription (Clark & Karmiloff-Smith Reference Clark and Karmiloff-Smith1993; Karmiloff-Smith Reference Karmiloff-Smith1994) may be the answer, that is, the spontaneous tendency of children to progressively explicate the implicit format of knowledge such that it becomes available for explicit reasoning to the general cognitive system. Representational redescription of temporal information implies different levels of increasing decontextualization – from full immersion in time to abstract reasoning about time. This process can be framed as bifurcation of a unitary system into a multilevel hierarchy. This makes ontogeny probably the most exciting time scale because it is the same child that at one point in his or her development is (still) stuck in time, then undergoes bifurcation and emerges from it as a deliberate cognizer enjoying temporal reasoning. In this process, the acquisition of tensed language may support tensed thought. Language as a symbolic code has the potential to equalize the indirect experience of past and future events vis-à-vis the direct experience of present events (Ünal & Hohenberger Reference Ünal and Hohenberger2017). Equally abstract (temporal) words and grammatical forms (tense, aspect) are used to refer to them.

Microgeny

The need for clarifying the relation between temporal updating and temporal reasoning becomes most pressing in adults because they avail of and use both systems, synchronously, in their daily behavior. How do they interact? Obviously, adults neither only temporally update nor only reason temporally. It is rather characteristic of us that we do both, at various times. The key feature that H&M mention in this context is flexibility. Through temporal reasoning, adults can arrive at the proper result even if novel information does not arrive in the original order of the event sequence. More generally, flexibility means that the two systems can be applied freely according to situational demands/constraints. This flexibility comes for free, enabled by the common self-organizing principle of bifurcation. H&M invoke bifurcation only at one point – when it comes to construing the (conscious) decision process of an adult choosing how his or her life shall temporally unfold in the future – in this or that direction. However, bifurcation is the general process behind the other (though unconscious) phylogenetic and ontogenetic changes as well; the change from the animal to the young child (that can only roughly distinguish present, past, and future) and the change from the young to the older child (that can distinguish increasingly better between any point in the proximal and distal past and future). Each time a further choice is enabled, a novel opportunity for the cognitive system to engage with temporality.

Last, I am concerned with H&M's characterization of the two contradictory elements of the “naïve theory of time”: on the one hand, the exclusive “now,” and on the other hand, the inclusion of the many nows into the overall flow of time. Already Husserl (Reference Husserl and Brough1917/1991) recognized the oxymoronic characteristic of the now as “standing-streaming” (Kelly Reference Kelly2008). Each now is standing while all nows are streaming. Husserl argues that the nontemporal phenomenal experience of the now (as standing) is necessary for a stable time consciousness to arise in the first place. Yet the now is not concluded. It contains in itself a little bit of the future and a little bit of the past. These extensions Husserl dubbed “protention” and “retention,” respectively. One may conceive of them as “time buds” from which the full temporal dimension may extend later on.

In conclusion, I have argued that the relation between H&M's two systems of temporal cognition may be conceived of as the result of a common principle of self-organization: bifurcation. Such a dynamical perspective helps integrate common observations across the phylogenetic, ontogenetic, and microgenetic time scales, as well as across species. Finally, it allows posing research questions whose determination is empirical.