In the Classical Arabic of the Quran the terms for heart and mind are often used interchangeably. This may seem strange for people who are only familiar with these terms in their modern use. The three words are قلب (qalb), صدر (sadr), and فاد (fawd).
In modern Arabic the Arabic word قلب (qalb) has typically the meaning of heart, but in the Classical Arabic of the Quran this word can mean both heart and/or mind. Here is a simple example to show this.
[7:179] We have committed to Hell multitudes of jinns and humans. They have minds with which they do not understand, eyes with which they do not see, and ears with which they do not hear. They are like animals; no, they are far worse—they are totally unaware.
وَلَقَدْ ذَرَأْنَا لِجَهَنَّمَ كَثِيرًا مِنَ الْجِنِّ وَالْإِنْسِ لَهُمْ قُلُوبٌ لَا يَفْقَهُونَ بِهَا وَلَهُمْ أَعْيُنٌ لَا يُبْصِرُونَ بِهَا وَلَهُمْ آذَانٌ لَا يَسْمَعُونَ بِهَا أُولَٰئِكَ كَالْأَنْعَامِ بَلْ هُمْ أَضَلُّ أُولَٰئِكَ هُمُ الْغَافِلُونَ
Consider that we use our ears for hearing. We use our eyes for seeing. So what do we use for understanding? One can say hearts, but a more accurate translation in this context is minds.
This is the same for the Arabic word صدر (sadr), which is typically translated as chest, but also can signify the mind as well. This is seen in the verse 17:51. For context let’s start from 17:49.
[17:49] They said, “After we turn into bones and fragments, we get resurrected anew?!” [17:50] Say, “Even if you turn into rocks or iron. [17:51] “Or whatever considerable creation of your mind ” They will then say, “Who will bring us back?” Say, “The One who created you in the first place.” They will then shake their heads and say, “When will that be?” Say, “It may be closer than you think.”
أَوْ خَلْقًا مِمَّا يَكْبُرُ فِي صُدُورِكُمْ فَسَيَقُولُونَ مَنْ يُعِيدُنَا قُلِ الَّذِي فَطَرَكُمْ أَوَّلَ مَرَّةٍ فَسَيُنْغِضُونَ إِلَيْكَ رُءُوسَهُمْ وَيَقُولُونَ مَتَىٰ هُوَ قُلْ عَسَىٰ أَنْ يَكُونَ قَرِيبًا
Now is it the heart that conjures up examples or the mind?
The other word in the Quran that can signify both the heart and mind is the word فاد (fawd). In Sura 53, when it discusses the ascension of prophet Muhammad’s soul to receive the Quran it makes the following statement in verse 11.
[53:11] The mind never made up what it saw.
(١١) مَا كَذَبَ الْفُؤَادُ مَا رَأَىٰ
Now is it typically the heart that determines what a person sees or their mind?
Now none of this is to indicate that these words always mean mind or that they cannot even insinuate heart in the verses provided, but just to show that translating these words as mind in certain occurrences is a more accurate translation than heart based on the function it is describing.