What is Philosophy?

I found the following on Keith's blog.  It is so good I simply must reproduce it here.

The nearest thing to a safe definition of the word "philosophy", if we wish to include all that has been and will be correctly so called, is that it means the activity of Plato in his dialogues and every activity that has arisen or will arise out of that.

(Richard Robinson, "Is Psychical Research Relevant to Philosophy?" The Aristotelian Society, supplementary volume 24 [1950]: 189-206, at 192.)

This is in line with my masthead motto which alludes to the famous observation of Alfred North Whitehead:

The safest general characterization of the European philosophical tradition is that it consists of a series of footnotes to Plato.  I do not mean the systematic scheme of thought which scholars have doubtfully extracted from his writings.  I allude to the wealth of general ideas scattered through them.  [. . .] Thus in one sense by stating my belief that the train of thought in these lectures is Platonic, I am doing no more than expressing the hope that it falls within the European tradition. (Process and Reality, Corrected Edition, The Free Press, 1978, p. 39)