Isaac Newton
Can't Say Why, Use It Anyway
Keep what you can calculate apart from what you can guess
Principia, second edition (1713), General Scholium
I only know how it moves. Newton shows what to do when the rule works and the cause is still missing.
What actually happened?
Newton's law of gravity could give the orbit of the Moon, the tides and the return of comets, and his critics kept pressing: how can two bodies far apart pull on each other? No rope, no collision, nothing in between to carry it. In 1713 he added a General Scholium to the second edition of the Principia and answered. He had not yet found the cause of gravity's properties in the phenomena, and he would 'frame no hypotheses'.
The rule, and the cause behind it
He kept two things apart. How strong gravity is and how it falls off with distance could be calculated and measured. Why it behaves so was a separate matter. He gave the first in full and left the second empty.
A doctor sees from the data that a drug works but does not know how. Using it and explaining it are two different questions.
Whatever was not drawn from the phenomena was a hypothesis
He used the word narrowly. If it was not deduced from observation, he called it a hypothesis, however plausible, and kept it out of his conclusions. You may think it. You may not file it in the same report as the figures.
You can show sales move with the weather. 'People are in a better mood' is your guess, and in the report it gets a line to itself.
Do not add a cause you do not need
At the start of the Principia he set out rules of reasoning, and the first is to admit no more causes than are true and enough to explain the thing. The extra one is your taste, not evidence.
Traffic fell and the data shows two changes you made. Check those two before you start wondering whether the algorithm changed.
How do I use it today?
Where you are: you have seen a rule that is useful, people are pressing you for why, and you are tempted to make something up to fill the gap.
Ask first: did I calculate this or guess it? Can I write the two in separate columns?
Where it goes wrong: reading it as do not act until you know. He kept using the law of gravity without knowing its cause; he simply wrote down that this column was still empty.
Lines to keep
Use the rule now; the cause can wait.
What you calculated and what you guessed need separate columns.
'I do not know yet' is an honest sentence.
Same situation, other people are asking
By the time the data is in, will it be too late?Everyone I know is in this. I don't actually understand it.I keep listing reasons this will work. Should I do the other list?Everything I know about this came up one reporting line.I don't have enough information · all 14 questions →If this one named what you are going through,
send it to someone who needs it, or keep it somewhere you will find it again.