This part of learning is therefore distinguished by the name of science, understood in its special and appropriate signification; and it is awarded by Aristotle to the province of the intellect or theoretic mind, as producing abstract, unchangeable' and necessary truths, which exclude from the understanding all kind of uncertainty, and also as containing in themselves the end for which they were contemplated'.

1

Περὶ τῶν μὴ ἐνδεχόμενων ἄλλως ἔχειν.-Aristot.

* ̓Αλλ ̓ ἔτι καὶ ἡ μαθηματικὴ θεωρητική. Αλλ' εἰ ἀκινήτων καὶ χωριςῶν ἐτι, νῦν ἄδηλον. Ὅτι μὲν ἦν ἔνια μαθήματα, τ ἀκίνητα καὶ ᾗ χωρισα, θεωρεῖ, δῆλον.—Aristot. Metaph. lib. vi. cap. 1.

3

Επισήμη μὲν ἦν τί ἐςιν, ἐντεῦθεν φανερὸν, εἰ δεῖ ἀκριβολογεῖσθαι, καὶ μὴ ἀκολυθεῖν ταῖς ὁμοιότησι πάντες γὰρ ὑπολαμ βάνομεν, ὃ ἐπισάμεθα μὴ ἐνδέχεσθαι ἄλλως ἔχειν. Τὰ δὲ ἐνδεχόμενα ἄλλως, ὅταν ἔξω τῷ θεωρεῖν γένηται, λανθάνει εἰ ἔσιν, ἢ μή. Εξ ἀνάγκης ἄρα ἐπὶ τὸ ἐπισητόν. Αΐδιον ἄρα. Τα γὰρ ἐξ ἀνάγκης ὄντα ἁπλῶς, ἀΐδια πάντα· Τὰ δ' αΐδια, ἀγένητα καὶ ἄφθαρτα. Ἔτι διδακτὴ πᾶσα ἐπιστημη δοκεῖ εἶναι, καὶ τὸ ἐπιστητὸν, μαθητέον.-Aristot. Εthic. Nicom. lib. vi. cap. 3. whence the science had the name Mathematics. Considered in their simple state, this observation may be just; but mathematics, when mixed with physics, or any subject capable of mensuration, produce other important ends, beyond what is contained in themselves. It is when considered in their simple state only, that the power of reason so prominently triumphs, for in this simple state it is alone

CHAP. II.

PHYSICS.

SECT. I.

The Logic of Physics.

HOUGH truth does not appear in the

TH

other departments of learning with that bold and irresistible conviction with which she presides in mathematical science, it shines through all, if not interrupted by prejudice or perverted by error, with a clear and useful though inferior strength. And as it is not necessary for his general safety or convenience that the traveller should always enjoy the heat and splendour of the mid-day

that long trains of reasoning can be formed. Of these the mathematician can produce thousands, which, though they may end in themselves, produce this further advantage, that they exercise the mind, strengthen the attention and memory, and habituate the reason to close and continuous efforts of patient investigation.

sun, whilst he can pursue his journey with more pleasure and convenience under the weaker influence of the morning or evening ray; so it is not requisite for the various concerns and purposes of life that men should be led by truth of the most redundant brightness.

On the contrary, it is in every view more useful and expedient for us, situated and circumstanced as we are, since Providence has left us in the confines of much darkness, to act and move under the shades of weaker yet sufficient evidence. Both reason and experience accordingly inform us, that the use and value of truth in general, as it is appointed in all its different divisions to attend us with its light through our transitory journey, does not bear any fixed proportion to its clearness and conviction.

Much of the most useful part of our knowledge is derived from a source different from that which has been just investigated; not from a few general ideas of two kinds of quantity abstracted and separated from all matter, but from the innumerable qualities

of individual and particular things as they are inherent and exist in matter-of all those bodies with which we are by nature every way surrounded, which are perpetually soliciting the external senses, and with whose uses we are immediately and necessarily concerned. To know their inherent powers and properties, their qualities and attributes, their motions and operations, their causes and effects, is to cultivate the various and extensive field of physics or natural philosophy.

Yet this part of learning, however it may differ from pure mathematics, is referred by the Peripatetic philosopher to the same province of mind, the speculative or theoretic intellect; because it derives its principles from those external subjects which it contemplates, and not from the exercise of the will respecting good or evil, nor from the internal resources of the mind contemplating and creating, as we shall hereafter find to be the case with ethics and poetry1.

1 Ἐπεὶ δὲ καὶ ἡ φυσικὴ ἐπισήμη τυγχάνει ἆσα περὶ γένος τὶ τῶ ὄντος (περὶ γὰρ τὴν τοιαύτην ἐςὶν ἐσίαν ἐν ᾖ, ἡ ἀρχὴ τῆς κινή

THE

SECT. II.

Of Physical Principles.

HE evidence of the external senses is obviously the primary principle from which all physical knowledge is derived.

But whereas nature begins with causes, which after a variety of changes produce effects, the senses open upon the effects, and from them, through the slow and painful road of experiment and observation, ascend

to causes.

Man appears upon the stage of this material system as on a visionary theatre, in which he looks only upon the exterior of things, as the eye upon a flower that is full

σεως καὶ τάσεως ἐν αὐτῇ) δῆλον ὅτι ἔτε πρακτική ἐτιν ὅτε ποιητική. Τῶν μὲν γὰρ ποιητικῶν ἐν τῷ ποιντι ἡ ἀρχὴ, ἢ νῆς ἐσιν, ἢ τέχνη, ἢ δύναμίς τις· τῶν δὲ πρακτικῶν, ἐν τῷ πράττοντι ἡ προαίρεσις. Τὸ αὐτὸ γὰρ τὸ πρακτὸν καὶ προαιρετόν. Ωςε εἰ ἡ ἅπασα διάνοια ἢ πρακτικὴ, ἢ ποιητική, ἢ θεωρητική, ἢ φυσικὴ θεωρητικὴ τις ἂν en-Aristot. Metaph. lib. vi. cap. 1.