Geomorphology 84 (2007) 159–169 www.elsevier.com/locate/geomorph The perfect landscape ⁎ Jonathan D. Phillips Tobacco Road Research Team, Department of Geography, University of Kentucky, Lexington, KY 40506-0027, United States Received 3 December 2004; received in revised form 2 January 2006; accepted 2 January 2006 Available online 17 July 2006 Abstract The “perfect storm” metaphor describes the improbable coincidence of several different forces or factors to produce an unusual outcome. The perfect landscape is conceptualized as a result of the combined, interacting effects of multiple environmental controls and forcings to produce an outcome that is highly improbable, in the sense of the likelihood of duplication at any other place or time. Geomorphic systems have multiple environmental controls and forcings, and degrees of freedom in responding to them. This allows for many possible landscapes and system states. Further, some controls and forcings are causally contingent. These contingencies are specific to time and place. Dynamical instability in many geomorphic systems creates and enhances some of this contingency by causing the effects of minor initial variations and small disturbances to persist, and grow disproportionately large, over time. The joint probability of any particular set of global controls is low, as the individual probabilities are <1, and the probability of any set of local, contingent controls is even lower. Thus, the probability of existence of any landscape or earth surface system state at a particular place and time is negligibly small: all landscapes are perfect. Recognition of the perfection of landscapes leads away from a worldview holding that landforms and landscapes are the inevitable outcomes of deterministic laws, such that only one outcome is possible for a given set of laws and initial conditions. A perfect landscape perspective leads toward a worldview that landforms and landscapes are circumstantial, contingent results of deterministic laws operating in a specific environmental context, such that multiple outcomes are possible. © 2006 Elsevier B.V. All rights reserved. Keywords: Perfect landscape; Contingency; Geomorphic system; Instability; Probability 1. Introduction convergence or coincidence of several different forces or factors to produce an unusual outcome. While the In his book by the same title, journalist Sebastian colloquial use of the perfect storm metaphor often Junger (1997) used the term “perfect storm” to refer to a connotes potential trouble or disaster, in this essay, I rare convergence in space and time of three different wish to pursue the other aspect of perfect storms: the weather systems to create a rare, if not unique, improbable combination of several individual factors to meteorological event. Since the publication of Junger's create a singular outcome. The “perfect landscape,” in book and a movie based on it, “perfect storm” has come this sense, would be the result of the combined, into general use as a metaphor for the improbable interacting effects of multiple environmental controls and forcings to produce an outcome that is highly ⁎ Tel.: +1 11 859 257 6950. improbable, in the sense of the likelihood of duplication E-mail address: [email protected]. at any other place or time. 0169-555X/$ - see front matter © 2006 Elsevier B.V. All rights reserved. doi:10.1016/j.geomorph.2006.01.039 160 J.D. Phillips / Geomorphology 84 (2007) 159–169 The idea that no two landscapes are identical in (iv) The joint probability of any particular set of local, minute detail is hardly novel. The argument developed contingent controls is very low, as the individual here seeks to go beyond this common wisdom to outline probabilities are ≪1. a view of geomorphology (and indeed field-based (v) The probability of existence of any landscape or environmental sciences and geography in general) that earth surface system state at a particular place and integrates local, contingent, historical explanation with time is negligibly small: all landscapes are perfect. global, nomothetic, deterministic explanation. This (vi) Recognition of the perfection of landscapes leads approach shifts the focus from a search for common, away from a worldview holding that landforms general universal laws which attempt to bring different and landscapes are the inevitable outcomes of landforms and landscapes under a common explanatory deterministic laws, such that only one outcome is umbrella, to an attempt to explain the spatial variability possible for a given set of laws and initial of earth surface systems. Models, generalizations and conditions. A perfect landscape perspective laws are based on the principle of ceteris paribus, all leads toward a worldview that landforms and other things being equal. In a perfect landscape, all other landscapes are circumstantial, contingent results things are never equal. of deterministic laws operating in a specific Despite the fact that no two locations are exactly environmental context, such that multiple out- alike, similarities do exist, commonalities can be comes are possible. identified, and there are physical and chemical laws (vii) These different worldviews are associated with that apply everywhere and always—and a far larger set fundamentally different research approaches. of looser laws, principles and generalizations that are widely if not universally applicable Culling (1987, 2. Multiple controls 1988) pointed out that landforms, landscapes and indeed spatial patterns in general virtually always have That geomorphic systems are affected by multiple regularities or identifiable patterns which can be controls is axiomatic. While particular controls such as explained with general laws, overlaid or combined lithology, climate or sea-level change may be empha- with irregularities and complexities. The focus on one or sized, even the simplest conceptual frameworks of the other–for instance the general concavo-convex landscape evolution implicitly or explicitly view land- hillslope profile or the fractal irregularities of the scapes as product of a combination of factors. W.M. detailed topographic profile–is largely a function of Davis (1909), for example, viewed the land surface as purpose and/or personal preference. Analogously, one the result of the combined effects of structure, process, can legitimately focus on those aspects of earth surface and stage (time). Davis' structure–process–time frame- systems explicable on the basis of general principles and work was implicitly and explicitly adopted by numerous common to other systems, or on those aspects that are earth scientists, regardless of the extent to which they local and historically contingent. adhered to Davis' cyclical model of landscape evolu- The argument here will be developed as follows: tion. Recognizing that “structure” can represent a variety of geological controls, that there are multiple processes (i) Landscapes and earth surface systems have in most landscapes, and that even the time factor can be multiple environmental controls and forcings, conceptualized in various ways, the structure–process– and degrees of freedom in responding to them. time trinity is fully consistent with notions of multiple This allows for many possible landscapes and controls and forcings. system states. Similarly, the “clorpt” model of Jenny (1941), (ii) Some of the controls and forcings are causally ultimately derived from the pedological work of contingent. These contingencies are specific to Dokuchaev (1883), sees soils as the product of the time and place. Dynamical instability in many combined, interacting effects of climate, organisms, geomorphic systems creates and enhances some relief (topography), parent material (geology), time and of this contingency by causing the effects of other factors which may be locally important. Johnson minor initial variations and small disturbances to and Hole (1994), Retallack (1994) and Holliday (1994) persist, and grow disproportionately large, over have outlined how this conceptual and operational time. model has been influential not just in pedology and soil (iii) The joint probability of any particular set of global geomorphology, but in geomorphology more generally, controls is low, as the individual probabilities are Quaternary geology, palaeoenvironmental studies, ≤1. geoarchaeology and physical geography. A more recent J.D. Phillips / Geomorphology 84 (2007) 159–169 161 development which recognizes not only multiple Conditionality occurs when an earth surface system causality but also mutual adjustment is the “brash” can proceed along two or more different developmental model of Huggett (1995, 1997), which views the pathways, according to the occurrence or magnitude of a biosphere (b), toposphere (r, relief), atmosphere (a), particular phenomenon—for instance, whether fires are pedosphere (s, soil) and hydrosphere (h) as a dynamical suppressed or not. Whether or not thresholds are system where each component may influence, and be exceeded can result in different developmental path- influenced by, each of the others. ways in geomorphic systems and contingent outcomes, termed landform singularities by Begin and Schumm 2.1. Degrees of freedom (1984). Johnson and Watson-Stegner (1987) provide several examples of how soils might follow regressive It is equally axiomatic that many geomorphic or progressive pedogenetic trends according to whether systems have numerous degrees of freedom, modes or or not particular events occur. mechanisms to respond to environmental controls