Don't LOOK at anything in a physics lab. Don't TASTE anything in a chemistry lab. Don't SMELL anything in a biology lab. Don't TOUCH anything in a medical lab.
and, most importantly:
Don't LISTEN to anything in a philosophy department.
How many philosophers does it take to change a light bulb?
1) "Hmmm ... well there's an interesting question isn't it?" 2) "Define 'light bulb' ..." 3) "How can you be sure it needs changing?" 4) Three. One to change it and two to stand around arguing over whether or not the light bulb exists.
Don't LOOK at anything in a physics lab.
How many philosophers does it take to change a light bulb?
"A philosopher," said the theologian, "is like a blind man in a darkened room looking for a black cat that isn't there."
The First Law of Philosophy: For every philosopher, there exists an equal and opposite philosopher.