A few years ago I bought a 900 page book, The Cambridge Dictionary of Philosophy (published 1995), to help develop definitions in Plusroot Theory. The Editor, Robert Audi, said, the book was comprehensive.
This is the most comprehensive and authoritative one-volume dictionary available in English. It is over 900 pages long, contains 4,000 entries and cross-references, and has been written by an international team of over 380 specialists in all areas of philosophy. It presents, in a accessible manner, the most up-to-date survey of philosophy yet produced by a community of professional philosophers. [Back Cover]
Robert Audi
Audi also said it was extensive.
This indispensable one-volume dictionary offers … Extensive, up-to-date surveys of all the subdisciplines of philosophy (ethics, epistemology, philosophy of mind, philosophy of science, philosophy of religion, metaphysic, and logic. [Back Cover]
Robert Audi
You can imagine my astonishment when I found there was no definition of ‘philosophy’ in this dictionary of philosophy. There are definitions of many specific philosophies, such as philosophical anthropology, philosophical behaviorism, the philosophy of action, philosophy of biology, and so on but they bypassed philosophy as such.
How can it be that a comprehensive, extensive dictionary of philosophy did not define philosophy?
Much puzzled by this omission, I read through the preface and hit pay dirt.
The editor, Robert Audi, rejected the etymological definition. He said,
Some readers might be surprised to find that there is no entry simply on philosophy itself. This is partly because no short definition is adequate. It will not do to defined ‘philosophy’, in the etymological way many have, as ‘the love of wisdom’: granting that it is natural for philosophers to love wisdom and for many lovers of wisdom to be inspired to pursue philosophy, a lover of wisdom can be quite unphilosophical, and even a good philosopher can be wise in at most a few domains of inquiry. [p xxv]
Robert Audi
Audi attempts a tentative definition.
Perhaps a great many philosophers (though certainly not all of them) would agree that philosophy is roughly the critical, normally systematic, study of an unlimited range of ideas and issues; but this characterization says nothing about what sorts of ideas and issues are central in philosophy or about its distinctive methods of studying them. In a way, this dictionary as a whole presents a conception of philosophy, one that is rich in content and widely representative of what has been, is, and perhaps will long continue to be, generally viewed as philosophical work. 
Those wanting a sense of what a good definition of ‘philosophy’ must encompass might fruitfully consider how one can define the concerns central to a number of major philosophers representing different periods, styles of philosophy, and cultures. [p xxv - xxvi]
Robert Audi
Audi then goes on with some examples.
One such list might include Plato, Aristotle, Aquinas, Descartes, Hume, Kant, Hegel, Mill, Peirce, Heidegger, and Wittgenstein. We might also try to construct a unifying characterization of some of the basic fields of philosophy – for instance epistemology, ethics, logic, and metaphysics – and beyond this one should also consider what is central in such subfields as aesthetics, philosophy of history, philosophy of language, philosophy of logic, philosophy of mind, philosophy of religion, and philosophy of science. Reading the entries on these philosophers and fields will probably yield a much better indication of what philosophy is than we could expect from even a thousand-word entry. [p xxvi]
Robert Audi
Audi in the above explanation tends to restrict philosophy to the academic world where people are professionally involved in making a career of it. Philosophy, from his point of view, is confined to an elite group who specialize in critical systems beyond the reach of normal commonsense.
What To Do?
The Cambridge Dictionary created an interesting problem by excluding a definition of “Philosophy” which is the central theme of their work. For centuries the term ‘philosophy’ had a clear and simple meaning. ‘Phil’ means “love”. ‘Soph’ means “wisdom”. ‘Philosophy’ means the love of wisdom. Rejecting this definition implies that the philosophy departments in Colleges and University no longer love wisdom. What do they teach if they do not teach the love of wisdom?
What does a person do who disagrees with this development?
Plus Definition of Philosophy
Philosophy =+df a love of wisdom. More specifically philosophy is a thoughtful examination of reality, especially problems involving ideals, truth, reason, discourse, and duty, accompanied by an attempt to put first things first and expose illusion.
Philosophy, as here defined, includes religion insofar as religion is reflective, realistic, promotes the requirements of sound rational thinking, aims to put first things first, advocates concern for the business of mankind, and tries to avoid illusion.
Divisions. Plusroot Theory, for convenience, divides philosophy into several broad divisions; 1) Intuitional, 2) Common, 3) Critical, 4) Professional, 5) Elemental. [See below]
Unless otherwise specified, in Plusroot Theory the term philosophy refers to the above definition and divisions. In this definition, philosophy is a universal subject that involves the vast majority of people. Most people crave knowledge and are anxious to be a part of a study that loves wisdom. everybody, who has enough intellectual maturity to seek truth and establish priorities, is a philosopher at heart.
Philosophy, from the Plusroot point of view, is the universal subject of mankind. Every functioning person has thoughts that go deeper than appearance. Even children can be little philosophers.
Philosophy is inclusive. It is everybody’s business. Each person is a powerhouse of intelligence. We all benefit when we tap each others knowledge.
Most people keep their profound philosophical thoughts deep inside themselves and rarely say a word. One reason for this is that, when less educated people try to express philosophical thoughts, it comes out sounding fatuous. This is because they don’t have the vocabulary they need to express the profundity of the thoughts they think. An important aspect of higher education is to provide people with terminology so they can speak about their insights in an proficient manner. Without the right tools, most will keep their intimate thoughts hidden inside. This is one reason well-formed definitions are important. [See Secret; Hidden]
People are easily damaged by mistakes made by professional philosophers. Mistakes that come from the top work their way down through society and hurt those with less formal education. (See Chapter 3. Rational Style)
Plusroot Theory intellectually arranges philosophy into several categories; Intuitional, common, critical, professional and elemental. These divisions blend one onto the other with no distinct line of separation. In practice we check one against another as we develop our knowledge.
Intuitional philosophy refers to subconscious inclinations to seek truth, to reason validly, and to establish wise priorities. These are unarticulated intellectual connections we entertain in our thought systems concerning first things.   
Common philosophy is workaday evaluation of reality and priorities that all proficient people mull over in their mind to some extent as they mature. Common philosophy is common but not necessarily shallow. Common philosophers can be uncommonly brilliant. When common philosophy is adequately sound we call it commonsense. (See Chapter Six, Common Sense)
Critical philosophy is self conscious reflection and deliberated examination of issues involved, usually articulated and discussed with others. 
Academic philosophy is critical philosophy in an academic and/or professional atmosphere. 
When people begin to self-consciously reflect on what they are thinking, deliberately examine the issues involved, articulate their ideas and discuss them with others, philosophy enters the critical realm. In critical reasoning, we intentionally search for explanations and guiding principles and make an effort to apply our principles to what we do. When we deliberately relate what we do to a goal, we reason critically. When we wonder, speculate, study, examine, experiment, ask pointed questions, seek answers, defend a position, and/or find fault, we reason critically. When critical philosophy becomes an academic subject and is pursued in a professional atmosphere it becomes philosophy as defined by Robert Audi in The Cambridge Dictionary of Philosophy. 
Elemental or Root
When we begin to focus and ponder on sub structures that sustain and guide our thinking, then we enter the elemental realm of elemental philosophy. Elemental examinations can be either common or critical.
The elements of philosophy are propositions. [See Proposition Essay]
Elemental philosophy (root theory) investigates the elements that underlie rational thinking. In elemental philosophy we study our own thoughts, think about our self, concentrate on our own reasoning, and check around for elemental mistakes (root errors). People in the elemental realm become interested in thinking about thinking. Elemental philosophy is a catch all phrase to include grammar, epistemology, logic, rhetoric, math, geometry, ideology, linguistics, semantics, dialectics and related subjects.
In the plus system, elemental and root are comprehensive terms to refer to reflective mentality where we seek to know more about our intellect and our thinking processes. (See Elemental Essay)
Affirmative Elemental Philosophy
Putting the above together, affirmative elemental philosophy refers to studies and teachings that support the requirements of sound rational thinking in a manner adequate for the occasion. Affirmative elemental philosophy is affirmative root theory. (See Affirmative Essay)
Affirmative elemental theory covers a wide field of research and stretches back in time. It includes any aspect of learning insofar as it supports clear understanding, impartial truth, right reason, fair play, good will, decent dialog, and wise priorities. The emphasis here is on affirmative. Affirmative elemental philosophy is theory that adequately promotes the requirements of sound rational thinking.
Plus root theory is the version of affirmative elemental philosophy introduced in The Roots of Sound Rational Thinking. For the most part, plus root theory reasserts what has already been said by others. However, affirmative ideas need reiterating in words for our time so they don’t become trampled under the hoofs of the noisy, negative herd. If we are to advance our abilities to progress in peace we must keep affirmative elemental philosophy alive and well.
Negative Philosophy
Lenin (1870-1924) regarded all philosophy as a partisan weapon in the class struggle, and he wielded his own philosophy polemically in the interests of communists revolution. [B615/PhilDic/1995p429]
When ‘philosophy’ is used as a weapon, it is no longer ‘love of wisdom’. It is no longer a search for truth. Instead it becomes propaganda designed to deceive the gullible. This kind of negative practice is a perversion at the very heart of discourse. If Lenin’s attitude becomes entrenched in the style of a society, the affirmative enterprise must go underground. Although few people have been so candid in expressing the guidelines of negative oriented ideology, Lenin’s methodology is not new. (See Negative Essay)