Loading slide
So the machine needs to ask a different kind of question. Not "how much is plum worth," but:
Are these two things true at the same time?
Is this both a cabernet and plummy? Is it both a viognier and apricotty?
That question has a name. It is asking about a combination: something that depends on two conditions holding together, rather than on either one separately.
# did you know?
If you completed Module 01 you have already built this pattern once. The last circuit you wired there said "one input or the other, but not both", and it could not be done with a single gate. It took an OR, an AND and a NOT, arranged in layers.
That pattern has a name too: exclusive or, usually shortened to XOR.
These four bottles are the same shape with wine in place of switches. Plum makes a bottle expensive, and so does apricot, but only when each meets the right grape. Either one alone tells you nothing, exactly as either switch alone told you nothing.
It defeated one layer of gates for the same reason it is about to defeat one layer of weights.
The last chapter's wines had no combinations in them. Every taste carried its own fixed worth, and the price was the parts added up. That is precisely the kind of pattern one layer of weights can learn, and it learned it perfectly.
This collection is built from combinations, and one layer of weights cannot represent a combination at all. Not badly. It has no way to express the idea.
It is worth being clear about how common this is, because the wine makes it sound like a curiosity.
A drug that helps one patient and harms another depends on a combination of the drug and the patient. A word that means one thing in one sentence and something else in another depends on a combination of the word and its context. Sarcasm is a combination of what was said and how. Nearly everything interesting is a combination of something.
Which makes this failure much more serious than one awkward case of wine. A machine that cannot represent combinations cannot learn most of what there is to learn.
So something has to be added.
Loading contents...