They're boolean (single bit of information) but not boolean (single bit interpreted as meaning true or false). The LED isn't true or false, the microcontroller pin isn't true or false.

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bsoles 5 days ago | parent | next [-]

This is semantic pedantry. The association true/1/high and false/0/low is well-known and understood.

	▲	kps 5 days ago \| parent [-]
		Plenty of signals are asserted (true) by being brought low, or have 1=low (e.g. CAN).

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marcellus23 5 days ago | parent | prev [-]

huh? The LED isn't true or false, but whether the LED is on is true or false.

	▲	simondw 5 days ago \| parent [-]
		And whether the LED is off is false or true.