My daughter is at an age (five) where she now sometimes likes to play in her room by herself. I poked my head in the other evening, and she was playing with some horse figurines (which I brought back when I interviewed for the job here at EKU). We exchanged a few words--Are you playing? Yes. Is everything ok? Yes. And then she said, "You can go now."
That was remarkable enough. Then later that evening (or maybe the next day--they run together too often) it struck me that just as she shuts herself into the room to play for awhile--to let her imagination run--so, too, I shut myself downstairs at night to play at doing philosophy. The thought hit me very quickly, and at first it seemed like a rather pessimistic one--I'm still just "playing." (Making things up? Pretending? Building castles in the air?) But later it occurred to me that this can't be a bad thing. Play is good, and good philosophy can be playful. Socrates could be playful, but also dead serious; this seems true of Wittgenstein, too. Play can be serious, insofar as keeping alive the imagination, and exercising it, is important business. Perhaps much more so than "growing up" and becoming consumed with the everyday crap which threatens to take away the time for play, and extinguish first our energy, and then our capacity, for imagination and vision.
So, yes, sometimes I'm just making things up, playing with ideas, parading them around the room like figurines. Is this a bad thing? I guess the question is: where is it going? To what end? But maybe the answer is: we can't know the answer ahead of time. And that is why the play is necessary, even when the ideas and problems philosophers play with are themselves quite serious.