There is no other species on the Earth that does science. It is, so far, entirely a human invention, evolved by natural selection in the cerebral cortex for one simple reason: it works. It is not perfect. It can be misused. It is only a tool. But it is by far the best tool we have, self-correcting, ongoing, applicable to everything. It has two rules. First: there are no sacred truths; all assumptions must be critically examined; arguments from authority are worthless. Second: whatever is inconsistent with the facts must be discarded or revised. We must understand the Cosmos as it is and not confuse how it is with how we wish it to be.
Our academic system rewards people who know a lot of stuff and generally we call those people smart, but at the end of the day who do you want- the person who can figure things out that they've never seen before or the person who can rattle off a bunch of facts?
Approach each new problem not with a view of finding what you hope will be there, but to get the truth, the realities that must be grappled with. You may not like what you find. In that case you are entitled to try to change it. But do not deceive yourself as to what you do find to be the facts of the situation.
Depend upon it there comes a time when for every addition of knowledge, you forget some thing that you knew before. It is of the highest importance, therefore, not to have useless facts elbowing out the useful ones.
I have no data yet. It is a capital mistake to theorize before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts.
A man should keep his little brain attic stocked with all the furniture that he is likely to use, and the rest he can put away in the lumber room of his library, where he can get it if he wants it.
The difference between a historian and a poet is not that one writes in prose and the other in verse -- indeed the writings of Herodotus could be put into verse and yet would still be a kind of history, whether written in metre or not. The real difference is this, that one tells what happened and the other what might happen. For this reason poetry is something more scientific and serous than history, because poetry tends to give general truths while history gives particular facts.
For the great enemy of truth is very often not the lie -- deliberate, contrived and dishonest -- but the myth -- persistent, persuasive, and unrealistic. Too often we hold fast to the clichés of our forebears. We subject all facts to a prefabricated set of interpretations. We enjoy the comfort of opinion without the discomfort of thought.
History is what happened, not what we wish had happened or what a theory says should have happened. One of the reasons for the great value of history is that it allows us to check our current beliefs against hard facts from around the world and across the centuries. But history cannot be a reality check for today's fashionable visions when history is itself shaped by those visions. When that happens, we are sealing ourselves up in a closed world of assumptions.
False facts are highly injurious to the progress of science, for they often long endure; but false views, if supported by some evidence, do little harm, as everyone takes a salutary pleasure in proving their falseness; and when this is done, one path towards error is closed and the road to truth is often at the same time opened.