40
M. E. D. P O O R E
It should be apparent from this example that the ecologist who uses
the method of successive approximation t o elucidate the problems of
vegetation is at the same time erecting classes and organizing his
knowledge in a scheme of relationships. In fact he is classifying his
data, and this classification is the most succinct and economical expression of his results.
Jevons (1913) describes the process of classification in this way:
“The usual mode in which an investigator proceeds t o form a classification of a new group of objects seems t o consist in tentatively arranging
them according t o their more obvious similarities. Any two objects
which present a close resemblance to each other will be joined and
formed into the rudiment of a class, the definition of which will at
first include all the apparent points of resemblance. Other objects as
they come to our notice will gradually be assigned t o those groups t o
which they present the greatest number of points of resemblance, and
the definition of a class will often have t o be altered in order t o admit
them. ”
The steps used by the descriptive ecologist are the same steps which
form a part of every attempt t o classify. Webb (1954) has named four
t o which two more, the first in the following list, have been added.
These are (i) selection of the stand t o be described; (ii) delimitation of
the stand t o be described; (iii) choice of features t o be described and
description of the stand; (iv) the delimitation and characterization of
abstract units of vegetation from the descriptions of stands; (v) the
nomenclaturet of vegetation units; and (vi) the arrangement of named
units in some sort of a system of classification.
Each of these steps has its own problems which are, at the same time,
problems in the method of successive approximation ; but before considering these, we should look into some of the general principles underlying all classifications.
11. THE CLASSIFICATION OF VEGETATION
Only limited advances are possible in any science without the orderly
arrangement of phenomena which is known as classification. Gilmour
(1951), in a brief and admirably lucid summary of the philosophical
principles of classification, has rightly said that classification is an
essential prerequisite of all conceptual thought. The logical assortment
of phenomena and their causes which must accompany any attempt a t
a serious classification gives an opportunity for the examination of all
the assumptions on which any system is based.
Many attempts have been made to construct classificatory systems
t The problems of nomenclature, though reel, ere outside the scope of this paper and
will not be clisrussecl.
M. E. D. P O O R E
It should be apparent from this example that the ecologist who uses
the method of successive approximation t o elucidate the problems of
vegetation is at the same time erecting classes and organizing his
knowledge in a scheme of relationships. In fact he is classifying his
data, and this classification is the most succinct and economical expression of his results.
Jevons (1913) describes the process of classification in this way:
“The usual mode in which an investigator proceeds t o form a classification of a new group of objects seems t o consist in tentatively arranging
them according t o their more obvious similarities. Any two objects
which present a close resemblance to each other will be joined and
formed into the rudiment of a class, the definition of which will at
first include all the apparent points of resemblance. Other objects as
they come to our notice will gradually be assigned t o those groups t o
which they present the greatest number of points of resemblance, and
the definition of a class will often have t o be altered in order t o admit
them. ”
The steps used by the descriptive ecologist are the same steps which
form a part of every attempt t o classify. Webb (1954) has named four
t o which two more, the first in the following list, have been added.
These are (i) selection of the stand t o be described; (ii) delimitation of
the stand t o be described; (iii) choice of features t o be described and
description of the stand; (iv) the delimitation and characterization of
abstract units of vegetation from the descriptions of stands; (v) the
nomenclaturet of vegetation units; and (vi) the arrangement of named
units in some sort of a system of classification.
Each of these steps has its own problems which are, at the same time,
problems in the method of successive approximation ; but before considering these, we should look into some of the general principles underlying all classifications.
11. THE CLASSIFICATION OF VEGETATION
Only limited advances are possible in any science without the orderly
arrangement of phenomena which is known as classification. Gilmour
(1951), in a brief and admirably lucid summary of the philosophical
principles of classification, has rightly said that classification is an
essential prerequisite of all conceptual thought. The logical assortment
of phenomena and their causes which must accompany any attempt a t
a serious classification gives an opportunity for the examination of all
the assumptions on which any system is based.
Many attempts have been made to construct classificatory systems
t The problems of nomenclature, though reel, ere outside the scope of this paper and
will not be clisrussecl.