“Positive data, positive data, positive data” – says the overbearing supervisor. What does it all mean? Well, essentially the terms positive and negative can only exist if you have a pre-existing stance on the outcome of an experiment. Scientists design experiments to test hypotheses. Indeed some of these experiments have a desirable outcome. That outcome being “a piece of the puzzle” or positive data, which falls beautifully with a little click amongst “puzzle pieces” of existing data you may already have before you.
However, the trick is to realise that there isn’t an existing puzzle to fill in the first place. I believe the best scientists are the ones that recognise that you’re not following a picture on a box. There is no box, there is no bloody template. Every time you conduct an experiment, nature is throwing a piece of a puzzle at you, some puzzle, not one that you’ve seen before. It’s your job to figure out if you can click some of these pieces of data together to complete a picture or even a partial picture which exists as a snapshot. For a moment this will be considered the prevailing thought on one of the mysteries of nature, until we discover more pieces to add, which ultimately adjusts the picture again.
This means negative data is just as important as positive data. A discovery that doesn’t fit in with what you have, is just as important as one that does fit the existing data, because it could be the missing part of another puzzle. Knowing to distinguish between the two and being nuanced about this is a delicate skill that can sometimes evaporate with the pressures of being a scientist.
Science is about truth. We as scientists cannot assume everything is true just because it fits a picture on a box. If we throw the box away we can appreciate that negative data is in fact a beautiful discovery in itself, because its no longer negative data, its just data, really useful data.
image credit: http://www.american-buddha.com/mondo.negative-positive.htm
minimolecule 
If everything counts as data, then the truth just becomes what your friends let you get away with. Does that say more about you, or more about your friends? Do your friends ever say to you, “You want the truth? You can’t handle the truth!!”
I’m just messing with you. Hope the writing is going well. Can’t believe you’re getting all philosophical about the scientific method. You must be on the ‘Phil’ bit of your DPhil. But, if you want to know more, check out what the term positivism means. Are you a positivist? All this talk about negative data and truth makes you sound quite positivist. On the other hand, your skepticism about pre-existing jigsaw puzzles suggests a considerable degree of relativism. Anyway, back to the truth. You might also want to check out funnel plots as a tool for checking what truth-seeking people think about people who they think are not being truthful. Good times. Yeah.