> First, what is a tree? It’s a big long-lived self-supporting plant with leaves and wood.

Hmm. This is a circular definition. You need to invoke tree to define leaves and wood.

No you don't.

Lots of plants have leaves. A few don't, some primitive because they hadn't evolved them yet (e.g. algae) and a few because they lost them (broom, cacti). If there were no trees and nobody had ever seen a tree you could still explain leaves.

Lots of plants have wood. Things that aren't trees have wood. They're called bushes. Wood is a thing separate from trees. Not all trees have wood: bananas grow on really big herbs that people call trees because they are tree-sized, but they're herbs. Palm trees aren't really made of wood.

	▲	hshshshshsh a day ago \| parent [-]
		Yeah. But that wood and that leaves of plant don't get you a tree. You are filling in the blanks that makes something a tree with information you already know about trees.

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williamdclt 2 days ago | parent | prev [-]

> You need to invoke tree to define leaves and wood.

I don't think so?

All non-tree plants have leaves (almost all maybe? edit: not cacti, so not all but most). Wood can be defined biologically ("cellulose fibers embedded in a lignin matrix" or something like that)

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hshshshshsh 2 days ago | parent [-]

Non tree plants still require you assume what a tree is.

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mrkickling a day ago | parent [-]

Ok, but all plants have leaves so you would only have to agree on what a plant is. You are trying to make a point but it makes no sense.

EDIT: you could also have totally separate definitions on what wood and leaves are without talking about trees or plants, don't you think?

	▲	hshshshshsh a day ago \| parent [-]
		Sure. But when most people think of plants they already use a tree like thing as mental model. People who have only seen non tree plants doesn't exist. And nor does any non tree plant leaves help you generate a tree leaf.