Use of the causitive form without an obvious source of causation


> 記憶を刈るという部分がメアを彷彿と **させる**

the part (of the story) where memories were reaped, resembles Mare.

> ファインダーを覗いてレンズをあちこちに **巡らせる** が、円盤の光は影を潜めている。

(operating a camera) while he peeked at the finder and looked around with the
lens, the disk's light had vanished.

> メアの頭を巣にしていたドラゴン（？）が、翼を **はためかせて** 浮遊した。

the dragon (?) nesting on Mare's head flapped it's wing and floated.

Is there some additional purpose of the causative form beyond making/allowing?

thank you




> 記憶を刈るという部分が[人々に]メアを彷彿とさせる

The "source of causation" is 記憶を刈るという部分. The agent ("causee") is unspecified,
but it's "generic you" (one/you/people/人/人々/etc). 彷彿(と)する means "to have
(something you've seen before) in mind", "to imagine (something) vividly". The
sentence literally means "The memory-reaping part makes people imagine メア," or
less literally, "The memory-reaping part reminds us of メア."

> [彼は]ファインダーを覗いてレンズをあちこちに巡らせる

The "source of causation" is the user of the camera, the implied subject of
the sentence. The agent is レンズ. 巡る is an intransitive verb meaning "to move
around". The causative part literally means "[He] makes the lens move around".

> メアの頭を巣にしていたドラゴン（？）が、翼をはためかせて浮遊した。

The "source of causation" is 'ドラゴン(?)', and the agent is 翼. はためく is an
intransitive verb meaning "to flap". The causative part literally means "The
dragon made the wings flap". English _flap_ works both transitively and
intransitively, but はためく is only intransitive, so you'll need はためかせる.

In case you're not sure why the agent is marked either by に or を, please read
[this](https://japanese.stackexchange.com/a/33515/5010). The point is that
彷彿(と)する is transitive, but 巡る and はためく are intransitive.




> 記憶を刈るという部分が[人々に]メアを彷彿とさせる

The "source of causation" is 記憶を刈るという部分. The agent ("causee") is unspecified,
but it's "generic you" (one/you/people/人/人々/etc). 彷彿(と)する means "to have
(something you've seen before) in mind", "to imagine (something) vividly". The
sentence literally means "The memory-reaping part makes people imagine メア," or
less literally, "The memory-reaping part reminds us of メア."

> [彼は]ファインダーを覗いてレンズをあちこちに巡らせる

The "source of causation" is the user of the camera, the implied subject of
the sentence. The agent is レンズ. 巡る is an intransitive verb meaning "to move
around". The causative part literally means "[He] makes the lens move around".

> メアの頭を巣にしていたドラゴン（？）が、翼をはためかせて浮遊した。

The "source of causation" is 'ドラゴン(?)', and the agent is 翼. はためく is an
intransitive verb meaning "to flap". The causative part literally means "The
dragon made the wings flap". English _flap_ works both transitively and
intransitively, but はためく is only intransitive, so you'll need はためかせる.

In case you're not sure why the agent is marked either by に or を, please read
[this](https://japanese.stackexchange.com/a/33515/5010). The point is that
彷彿(と)する is transitive, but 巡る and はためく are intransitive.

