Francis Bacon · Science
How three tables and ruthless exclusion wrung the secret of heat from nature.
A list of hot things cannot tell you what heat is. The sun’s rays, flame, boiling liquids, quicklime, fresh horse-dung, the warmth inside animals. All are hot, and they share countless other features, any of which might be the culprit.
So Francis Bacon adds a second list. Beside each hot thing he sets a near-twin that lacks the heat: the rays of the moon and stars, bright like the sun and yet not warm. Brightness dies there. It cannot be what heat is. Absence does the cutting work, not presence.
The move belongs to the Novum Organum of 1620, where Bacon allows only two ways of searching for truth. One flies from a handful of cases to the widest axiom. The other spins conclusions from first principles taken on authority, never returning to the world. Both roads end in cobwebs of words rather than knowledge of things.
He wants a third way, beginning in the senses and refusing to jump. Refusing is the hard part, because the mind, left alone, would have named heat after the third hot thing.
True induction throws things out. It does not merely gather instances where a nature appears; it hunts the cases where the nature is absent, and the cases where it varies in degree. Above all it proceeds by exclusion - throwing out every candidate the instances contradict. What survives the rejection, Bacon trusts, is the truth.
This is not the loose ‘induction by simple enumeration’ the logicians used. There you count up positive instances, this swan is white, that swan is white, and announce a rule. Bacon thought that kind of counting childish and unsafe, because a single contrary case can overturn it.
Not everyone grants that rejection earns the conclusion. David Hume would argue, a century and a half later, that the step from the observed past to the unobserved future cannot be rationally justified at all. If he is right, no rigour in the tables can make the ladder safe.
Bacon’s whole answer to such a doubt is discipline. To make it exact rather than haphazard, he organised the evidence into three great Tables of Investigation.
Bacon works his method in Book II on one question: the nature, or ‘form’, of heat. He builds three tables.
The Table of Presence lists every instance in which heat is found: the sun’s rays, flame, boiling liquids, quicklime sprinkled with water, even fresh horse-dung and the internal warmth of animals. The Table of Absence sets against each one a closely related case that lacks heat. The rays of the moon and stars are bright yet not warm; ordinary air is not hot of itself. The Table of Degrees records where heat increases and decreases: a body grows hotter with motion and friction, animals are warmer when they exercise.
The three together let the philosopher exclude. A true form of heat must be present in every instance of presence, absent in every instance of absence, and must rise and fall with heat in the table of degrees. Anything that fails even one of these tests is rejected.
What survives is not a substance. Heat, Bacon concludes, is a motion - a restrained expansive stirring of small particles. He calls this cautious first conclusion the ‘First Vintage’, and it is worth no more than the rejections that produced it.
This is the opening of the lesson. The rest — the dialogue, the primary source, and the recall — is in the app.
Reconstruct Bacon’s true induction from memory: the three tables he builds, what he does with them once they are filled, and where the heat inquiry ended.
Leads to David Hume.
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