ALBERT

Notes: Book Reviews

Notes: Purpose - The purpose of this paper is to highlight the influence of the late Heinz von Foerster in the life of an admirer and friend who remains a leader in the field of family therapy. Design/methodology/approach - The approach is autobiographical. The method is (loosely) process recall and personal theoretical reflection. Objectives are achieved by organizing major tenets of von Foerster's constructivism into personal categories of meaning. Findings - Findings included a deep philosophical influence on the author's professional life; an abiding impact on his personal life; and a durability of von Foerster's ideas across disciplines, time, and the ever-changing theories and politics of the mental health profession. Originality/value - This paper adds value to the social sciences in general, and to the field of family therapy in particular, because it highlights the interconnectedness of person and profession and the confluence of the messenger/message. Some might say this is cybernetics in vivo. There may be little that is "new" in this paper in terms of theoretical constructs, but the autobiographical nature of the reflections may be its most valuable contribution to others struggling with such concepts.

Notes: Abstract Amplitude distributions, which are nearly Gaussian, have been calculated for radial velocity, continuum brightness, spectral line equivalent width and spectral line central residual intensity fluctuations measured from high-dispersion high-resolution spectrograms taken at the center of the solar disk. The RMS and skewness S for each distribution have been calculated in a manner which allows testing of the homogeneity of the granulation pattern (i.e. variations in its statistics across the solar disk and with time). Pattern inhomogeneity across the disk is strongly indicated, and further evidence suggesting appreciable pattern persistence over time intervals ≳ 15 minutes is presented. The possibilities for investigations of S and its associated bi-spectrum are discussed. The qualitative values of S obtained are shown not to be due to unusually bright, rising granules (though a statistical tendency towards such granules is possible). An attempt to explain S for continuum brightness fluctuations in terms of the nonlinear effects of Planckian emission and opacity fluctuations in a stratified photosphere, leads to contradiction with the measured amplitude distributions, a contradiction which is probably due to an oversimplified treatment of radiative transfer in an inhomogeneous photosphere.

Notes: Abstract The application of the fast-Fourier-transform (FFT) algorithm to calculating one-dimensional and bi-dimensional (temporal and spatial), power and cross-power (coherence and phase) spectra is examined for solar photospheric fluctuations. Alternative methods for smoothing raw spectra, direct averaging (employing various weights) and indirect truncation of the correlation function, are compared, and indirect smoothing is compared with spectra calculated by mean-lagged-product (MLP) methods. Besides providing the raw spectrum, FFT techniques easily allow computing a series of spectra with varying amounts of smoothing. From these spectra a range of satisfactory compromise between resolution and stability can be determined which helps in the interpretation of spectral trends, and in identifying more clearly the existence and significance of spectral features. For bi-dimensional spectra presented as contour plots, this range of satisfactory smoothing can be restricted, particularly when spectral trends must be represented by small-scale contours. Equivalent spectra (i.e. comparable equivalent degrees of freedom) computed or smoothed by different methods have minor, but not negligible, differences. Examination of these differences favors computing of FFT spectra smoothed by averaging for photospheric fluctuations.

Notes: Abstract Fluctuations measured from a time sequence of high-resolution, high-dispersion Sacramento Peak Observatory spectrograms and previously analyzed by computing one-dimensional temporal and spatial spectra (Edmonds et al., 1965), are re-analyzed using bi-dimensional (temporal and spatial) power, coherence and phase spectra computed by fast-Fourier-transform techniques. The fluctuations measured are radial velocity for the FeI 5049.83, CrI 5051.91 and CI 5052.16 spectral lines, continuum brightness, and equivalent width and central intensity of the CI line. The bidimensional spectra, particularly those of coherence and phase, allow isolating different components of the fluctuations to a degree not possible in the one-dimensional analyses. Six components of the fluctuations have been isolated (Section 5 and Figure 11); the first three components are well-known but the nature of the remaining three is less certain: (1) Supergranulation which exists only in radial-velocity fluctuations and increases in power with depth. (2) Five-minute oscillations that dominate long-wavelength radial-velocity fluctuations, which may contribute of the order of one percent to continuum brightness and equivalent width fluctuations, and are waves which can propagate across the Sun's surface and possibly travel upwards at less than 70 km s−1. (3) A long-period, convective component which extends over all but very long wavelengths, is characterized by strong correlation between the radial velocity and photometric fluctuations, and involves low power levels for the radial velocity fluctuations. Seemingly, the radial velocity fluctuations lead those of continuum brightness by roughly 20 s. (4) Low and moderate wavenumber fluctuations which seemingly extend over frequencies ≲ 6 × 10−3 Hz and are characterized by low power levels for all types of fluctuations. It is difficult to deny the physical reality and distinctness from other components of these fluctuations, but whether they constitute a single component is uncertain. The radial velocity fluctuations seem to have the same phase relations with respect to each other as the five-minute oscillations. The continuum brightness fluctuations seem to lag the equivalent width fluctuations by roughly 17 s, lead the central intensity fluctuations by roughly 10 s, and lead the radial velocity fluctuations by roughly 15 to 20 s. (5) Possible line-formation (as distinct from continuum formation) brightness fluctuations at the center of the CI 5052.16 line, which seemingly are of low frequency and long wavelength and are poorly correlated with continuum brightness and radial velocity fluctuations. (6) A low-correlation, primarily photometric component restricted to long-periods and to wavelengths only slightly less than those of super-granulation. Its existence is suggested by a phase anomaly indicating that the radial velocity fluctuations lead the photometric fluctuations by roughly 4 min.

Notes: Abstract The fractional convective flux πF c (x c /πF) is computed for the effective level x c = logτ c = 0.125, using bi-dimensional co-spectra for relative continuum-brightness fluctuations ΔI and radial velocity fluctuations ΔV measured for the C i 5052.16 spectral line. A more uncertain flux for x Fe ≈ - 0.9 is obtained for the Fe i 5049.83 line. Since the results (Figure 1) incorporate current uncertainties in RMS ΔI , RMS ΔV and RMS ΔT (x), where ΔT are photospheric temperature fluctuations, they must be considered qualitative until these uncertainties are appreciably reduced. The requirement that the fractional convective flux 〈 1, places restrictions on these uncertainties which suggest that current RMS ΔT (x)'s are too large. The results confirm the importance of overshoot at the top of the solar hydrogen convection zone and suggest a non-negligible fractional convective flux throughout the lower photosphere. Qualitatively, they do not agree with the predictions of the generally-used, local, mixing-length theory or those of Parsons' (1969) modified mixing-length theory. However, qualitative agreement with the predictions of the non-local, generalized mixing-length theory of Spiegel (1963) and with the non-local theory of Ulrich (1970) cannot be considered as observational confirmation of these theories.

Notes: Conclusions Bradley succeeded in conceptualizing biological productivity in terms—monetary investment vs. profit—that could be applied to organisms as different in form and habitat as trees, grapevines, and crayfish.41 This form of measurement was not precise enough to have served as a basis for actual comparisons of production rate. His way of thinking, however, could have been applied with other terms of measurement once the usefulness of such measurements had been realized. The realization that production rate is an important factor is implicit in his discussions, but for his purposes, yearly yields were generally sufficiently precise determinations. Although Bradley drew substantially upon the contributions of others, his writings represent a significant beginning for productivity ecology. All of the kinds of investigations that he reported could have been extended, rendered more precise, and formed the basis of ecological generalizations during the eighteenth century. There were, however, certain conceptual limitations imposed by a lack of relevant knowledge in physiology and in physical science. A good understanding of productivity ultimately depends upon an understanding of metabolism, which in turn depends upon an understanding of photosynthesis, respiration, biochemistry, and the first and second laws of thermodynamics. The essential knowledge of these subjects would not be available until decades after Bradley's time.

Notes: Summary and conclusions Darwin's theory of evolution brought to an end the static view of nature. It was no longer possible to think of species as immortal, with secure places in nature. Fluctuation of population could no longer be thought of as occurring within definite limits which had been set at the time of creation. Nor was it any longer possible to generalize from the differential reproductive potentials, or from a few cases of mutualism between species, that everything in nature was “fitted to produce general ends, and reciprocal uses.” 134 The appeal to “design” could no longer be substituted for answers to questions concerning animal demography. Instead, the dynamics of a population had to be viewed as the outcome of species' struggle against animate and inanimate factors in the environment. Both the members of a species and the environmental factors tend to vary randomly, and therefore neither evolution nor population dynamics could be fully understood alone. For this reason Darwin's linking of the two subjects was inevitable and not merely an historical accident. Since Darwin had shown that no automatic equilibrium existed, he demonstrated the importance of closer study of the causes of population dynamics and extinction. He also indicated that an understanding of population depends upon the development of a broad knowledge in ecology. Viewed from another direction, Darwin's work ended the early modern era of population studies by clarifying three interrelated problems which were important for understanding population: extinction, distribution, and the nature of species. The components of his answer had been discussed in the eighteenth century, but there had not existed enough evidence for the completion of the revolution in thought which had then begun. At the beginning of the nineteenth century, Playfair found the evidence for extinction conclusive, and, in spite of Lamarck, Curvier convinced the scientific world that there could no longer be any doubt about it. This was a step the importance of which, with his limited knowledge of biogeography and population, Cuvier could not have fully realized. Lamarck attempted, with his evolutionary theory, to circumvent the necessity for admitting extinction, but he overestimated the adaptability of organisms and in doing so he underestimated the importance of competition and the whole field of ecology. On the other hand, he was not willing to let questions such as the origin of species remain taboo to science. The origin of species was a biogeographical as well as a paleontological question. Humboldt correlated environment with the distribution of species and conveyed the impression that plant communities are subject to change. De Candolle, following the lead of Linnaeus and Humboldt, emphasized the ecological aspects of biogeography, not only the importance of habitat and range, clearly showing the ecological effects of competition. The entomologists Kirby and Spence took a faltering step toward understanding the relationship between population and ecological role, but they fell short of any significant new conclusions. Neither they nor Swainson could fully comprehend the new perspective of De Candolle. Lyell was able to bring together the evidence from these three lines of investigation and weave them into an important synthesis that almost accomplished that Darwin later did. Although opposing Lamarck's theory of evolution, Lyell had a dynamic view of ecology. He realized that population dynamics offered an important key to the understanding of biogeography. Since he knew that species become extinct, he investigated closely the factors which could either preserve or extinguish species. While explaining these factors, he described the interrelationships of species in greater detail than had ever been done before. Forbes continued to develop Lyell's ecological concepts, and his first-hand field experience enabled him to describe biotic communities more concretely than Lyell had. Having the advantages of Lyell's understanding and his own experience from a global voyage, Darwin could take the final step from the static to the dynamic concept of life. He had seen populations fluctuating and also fossil species in South America, and on the Galapagos Islands he had encountered a biogeographical problem that could not be credibly solved without the idea of evolution. However, the bare idea of evolution did not fully answer his questions. He sought physiological causes of extinction before he read Malthus and realized that De Candolle and Lyell had correctly emphasized the importance of competition. Darwin found that, in order to understand evolution, he needed to improve his understanding of ecology. He wanted to know when populations were most easily decimated, how extensive were competition and cooperation, what effects parasites have upon populations, and what changes occur in biotic communities when a species is either added or subtracted. He contributed to some extent to answering these questions. Though there remained much for others to do, there was now a new and more secure theoretical framework within which later studies could be interpreted. As Ernst Mayr has observed, Darwin's “consistent thinking in terms of population has had an impact on biological theory and practice which is second only to his sponsorship of natural selection as the mechanism of evolution.” 135

Notes: Conclusions I have attempted to clarify some of the pathways in the development of Darwin's thinking. The foregoing examples of influence by no means include all that can be found by comparing Darwin's writings with Humboldt's. However, the above examples seem adequate to show the nature and extent of this influence. It now seems clear that Humboldt not only, as had been previously known, inspired Darwin to make a voyage of exploration, but also provided him with his basic orientation concerning how and what to observe and how to write about it. An important part of what Darwin assimilated from Humboldt was an appreciation of population analysis as a tool for assessing the state of societies and of the benefits and hardships which these societies can expect to receive from the living world around them. Darwin exhibited in his Journal of Researches a casual interest in the economic and political conditions of the countries he visited, but these considerations were much less important to him than to Humboldt. Instead, Darwin, with the assistance of Lyell's Principles of Geology, shifted from Humboldt's largely economic framework to a biological one built around the species question. This shift led Darwin away from a consideration of how the population biology of animals was related to man's economy to focus instead upon how population biology fitted into the economy of nature. Humboldt's Personal Narrative served very well as a model for Darwin's Journal of Researches, thereby helping Darwin gain scientific eminence. The Journal of Researches, like virtually all of Humboldt's writings, was a contribution to scientific orthodoxy. But Darwin had, along the way, acquired an urge to do more than just add his building blocks to the orthodox scientific edifice. He decided to rearrange those blocks of knowledge into a different structure, and for that task neither Humboldt's Personal Narrative nor any other of his works could serve as a model. Humboldt had lacked the confidence which Darwin needed that biogeography and the origin of species could be understood. Humboldt had not explored very far the possible connections between biology and geology. Nor had he provided a general synthetic account of population biology. Had he done so, he might have been more explicit about the extent of his endorsement of Malthus. But even if he had, Humboldt's strong orientation toward cooperation would probably have inhibited his recognition of the importance of competition in nature. Lyell, who had also benefited from reading Humboldt, gave Darwin insights that were lacking in Humboldt's Personal Narrative. Lyell admirably demonstrated how stratigraphy, paleontology, biogeography, and population biology could be interrelated, and his reasons for doing so were essentially the same as Darwin's. Lyell's understanding of biogeography and ecology came from the writings of Augustin-Pyramus de Candolle as much as from Humboldt's, and from the former Lyell derived an appreciation for the importance of competition and also a confidence that the mysteries of biogeography could be explained.117 Furthermore, Lyell's discussion of all these subjects and also of evolution in his Principles of Geology is a good synthetic argument that was the ideal model for Darwin's greatest book. Darwin, having become convinced that species change through time, was able to synthesize in his mind the contributions which he had derived from the writings of Humboldt and Lyell as they applied to the species question. When Darwin wrote his Journal of Researches there were two large gaps in his thinking about evolution that bothered him—the mechanism of evolution and the causes of extinction. It was only after reading Malthus in 1838 that he realized, as Lyell had more or less pointed out, how important was competition in nature. He now had the general outlines for his theory, and in the 1845 abridged edition of his Journal, now retitled The Voyage of the Beagle, he inserted a fuller discussion of competition in nature which showed his awareness of its importance as an ecological factor.118

Notes: Summary and conclusions Leeuwenhoek's observations relating to animal population, though scattered through many letters written during a period of over forty years, when seen in toto, were important contributions to the subject now known as animal demography. He maintained enough contact with other scientists to have received encouragement and some helpful suggestions, but the language barrier and the novelty of doing microscopic work forced him to be resourceful, inventive, and original. His multifarious investigations impinged upon population biology before he discovered a direct interest in it. He devised methods for estimating numbers of animalcules, and then he went on to estimate the population of the world. His interest in reproduction was an important avenue by which he approached the subject of reproductive capacity. Other important approaches were his studies of growth, longevity, and life histories. He discovered relationships between aspects of the life history, longevity, and reproductive capacity of several species of insects, notably calanders, scavenger flies, crane flies, aphids, and lice. An important feature of these investigations were the arithmetical calculations which he made of reproductive potentials. In spite of several limitations, these calculations were an important innovation to the study of animal population. In his later years, his investigations came more and more within the sphere of ecology. He made the first significant observations on food chains. It is especially interesting that fish were the subject of these observations, because it was not until the latter half of the nineteenth century that scientists realized that fish ultimately depend upon phytoplankton. These accomplishments did not pass unnoticed. Although Leeuwenhoek never synthesized his scattered observations concerning population, his originality and perception were appreciated by outstanding biologists of the eighteenth century. The important discussions of population biology by Réaumur, Buffon, and Bonnet all derived inspiration and assistance from the writings of Leeuwenhoek.73 This ingenious Fellow of the Royal Society, “by detecting through diligent application and scrutiny the mysteries of Nature and the secrets of natural philosophy,”74 became one of the founders of animal demography.